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path: root/drivers/tty/serial/8250
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2020-06-07Merge tag 'tty-5.8-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial driver updates from Greg KH: "Here is the tty and serial driver updates for 5.8-rc1 Nothing huge at all, just a lot of little serial driver fixes, updates for new devices and features, and other small things. Full details are in the shortlog. All of these have been in linux-next with no issues for a while" * tag 'tty-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (67 commits) tty: serial: qcom_geni_serial: Add 51.2MHz frequency support tty: serial: imx: clear Ageing Timer Interrupt in handler serial: 8250_fintek: Add F81966 Support sc16is7xx: Add flag to activate IrDA mode dt-bindings: sc16is7xx: Add flag to activate IrDA mode serial: 8250: Support rs485 bus termination GPIO serial: 8520_port: Fix function param documentation dt-bindings: serial: Add binding for rs485 bus termination GPIO vt: keyboard: avoid signed integer overflow in k_ascii serial: 8250: Enable 16550A variants by default on non-x86 tty: hvc_console, fix crashes on parallel open/close serial: imx: Initialize lock for non-registered console sc16is7xx: Read the LSR register for basic device presence check sc16is7xx: Allow sharing the IRQ line sc16is7xx: Use threaded IRQ sc16is7xx: Always use falling edge IRQ tty: n_gsm: Fix bogus i++ in gsm_data_kick tty: n_gsm: Remove unnecessary test in gsm_print_packet() serial: stm32: add no_console_suspend support tty: serial: fsl_lpuart: Use __maybe_unused instead of #if CONFIG_PM_SLEEP ...
2020-06-06Merge tag 'pci-v5.8-changes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci Pull PCI updates from Bjorn Helgaas: "Enumeration: - Program MPS for RCiEP devices (Ashok Raj) - Fix pci_register_host_bridge() device_register() error handling (Rob Herring) - Fix pci_host_bridge struct device release/free handling (Rob Herring) Resource management: - Allow resizing BARs for devices on root bus (Ard Biesheuvel) Power management: - Reduce Thunderbolt resume time by working around devices that don't support DLL Link Active reporting (Mika Westerberg) - Work around a Pericom USB controller OHCI/EHCI PME# defect (Kai-Heng Feng) Virtualization: - Add ACS quirk for Intel Root Complex Integrated Endpoints (Ashok Raj) - Avoid FLR for AMD Starship USB 3.0 (Kevin Buettner) - Avoid FLR for AMD Matisse HD Audio & USB 3.0 (Marcos Scriven) Error handling: - Use only _OSC (not HEST FIRMWARE_FIRST) to determine AER ownership (Alexandru Gagniuc, Kuppuswamy Sathyanarayanan) - Reduce verbosity by logging only ACPI_NOTIFY_DISCONNECT_RECOVER events (Kuppuswamy Sathyanarayanan) - Don't enable AER by default in Kconfig (Bjorn Helgaas) Peer-to-peer DMA: - Add AMD Zen Raven and Renoir Root Ports to whitelist (Alex Deucher) ASPM: - Allow ASPM on links to PCIe-to-PCI/PCI-X Bridges (Kai-Heng Feng) Endpoint framework: - Fix DMA channel release in test (Kunihiko Hayashi) - Add page size as argument to pci_epc_mem_init() (Lad Prabhakar) - Add support to handle multiple base for mapping outbound memory (Lad Prabhakar) Generic host bridge driver: - Support building as module (Rob Herring) - Eliminate pci_host_common_probe wrappers (Rob Herring) Amlogic Meson PCIe controller driver: - Don't use FAST_LINK_MODE to set up link (Marc Zyngier) Broadcom STB PCIe controller driver: - Disable ASPM L0s if 'aspm-no-l0s' in DT (Jim Quinlan) - Fix clk_put() error (Jim Quinlan) - Fix window register offset (Jim Quinlan) - Assert fundamental reset on initialization (Nicolas Saenz Julienne) - Add notify xHCI reset property (Nicolas Saenz Julienne) - Add init routine for Raspberry Pi 4 VL805 USB controller (Nicolas Saenz Julienne) - Sync with Raspberry Pi 4 firmware for VL805 initialization (Nicolas Saenz Julienne) Cadence PCIe controller driver: - Remove "cdns,max-outbound-regions" DT property (replaced by "ranges") (Kishon Vijay Abraham I) - Read 32-bit (not 16-bit) Vendor ID/Device ID property from DT (Kishon Vijay Abraham I) Marvell Aardvark PCIe controller driver: - Improve link training (Marek Behún) - Add PHY support (Marek Behún) - Add "phys", "max-link-speed", "reset-gpios" to dt-binding (Marek Behún) - Train link immediately after enabling training to work around detection issues with some cards (Pali Rohár) - Issue PERST via GPIO to work around detection issues (Pali Rohár) - Don't blindly enable ASPM L0s (Pali Rohár) - Replace custom macros by standard linux/pci_regs.h macros (Pali Rohár) Microsoft Hyper-V host bridge driver: - Fix probe failure path to release resource (Wei Hu) - Retry PCI bus D0 entry on invalid device state for kdump (Wei Hu) Renesas R-Car PCIe controller driver: - Fix incorrect programming of OB windows (Andrew Murray) - Add suspend/resume (Kazufumi Ikeda) - Rename pcie-rcar.c to pcie-rcar-host.c (Lad Prabhakar) - Add endpoint controller driver (Lad Prabhakar) - Fix PCIEPAMR mask calculation (Lad Prabhakar) - Add r8a77961 to DT binding (Yoshihiro Shimoda) Socionext UniPhier Pro5 controller driver: - Add endpoint controller driver (Kunihiko Hayashi) Synopsys DesignWare PCIe controller driver: - Program outbound ATU upper limit register (Alan Mikhak) - Fix inner MSI IRQ domain registration (Marc Zyngier) Miscellaneous: - Check for platform_get_irq() failure consistently (negative return means failure) (Aman Sharma) - Fix several runtime PM get/put imbalances (Dinghao Liu) - Use flexible-array and struct_size() helpers for code cleanup (Gustavo A. R. Silva) - Update & fix issues in bridge emulation of PCIe registers (Jon Derrick) - Add macros for bridge window names (PCI_BRIDGE_IO_WINDOW, etc) (Krzysztof Wilczyński) - Work around Intel PCH MROMs that have invalid BARs (Xiaochun Lee)" * tag 'pci-v5.8-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (100 commits) PCI: uniphier: Add Socionext UniPhier Pro5 PCIe endpoint controller driver PCI: Add ACS quirk for Intel Root Complex Integrated Endpoints PCI/DPC: Print IRQ number used by port PCI/AER: Use "aer" variable for capability offset PCI/AER: Remove redundant dev->aer_cap checks PCI/AER: Remove redundant pci_is_pcie() checks PCI/AER: Remove HEST/FIRMWARE_FIRST parsing for AER ownership PCI: tegra: Fix runtime PM imbalance on error PCI: vmd: Filter resource type bits from shadow register PCI: tegra194: Fix runtime PM imbalance on error dt-bindings: PCI: Add UniPhier PCIe endpoint controller description PCI: hv: Use struct_size() helper PCI: Rename _DSM constants to align with spec PCI: Avoid FLR for AMD Starship USB 3.0 PCI: Avoid FLR for AMD Matisse HD Audio & USB 3.0 x86/PCI: Drop unused xen_register_pirq() gsi_override parameter PCI: dwc: Use private data pointer of "struct irq_domain" to get pcie_port PCI: amlogic: meson: Don't use FAST_LINK_MODE to set up link PCI: dwc: Fix inner MSI IRQ domain registration PCI: dwc: pci-dra7xx: Use devm_platform_ioremap_resource_byname() ...
2020-06-02serial: 8250_early: Support kgdboc_earlyconDouglas Anderson
Implement the read() function in the early console driver. With recent kgdb patches this allows you to use kgdb to debug fairly early into the system boot. We only bother implementing this if polling is enabled since kgdb can't be enabled without that. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20200507130644.v4.11.I8f668556c244776523320a95b09373a86eda11b7@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-05-29serial: 8250_fintek: Add F81966 SupportJi-Ze Hong (Peter Hong)
Fintek F81966 is a LPC/eSPI to 6 UARTs SuperIO. It has fully compatible with F81866. It's also need check the IRQ mode with system assigned. F81966 IRQ Mode setting: 0xf0 Bit1: IRQ_MODE0 Bit0: Share mode (always on) 0xf6 Bit3: IRQ_MODE1 Level/Low: IRQ_MODE0:0, IRQ_MODE1:0 Edge/High: IRQ_MODE0:1, IRQ_MODE1:0 Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com> Cc: Ji-Ze Hong (Peter Hong) <peter_hong@fintek.com.tw> Link: https://lore.kernel.org/r/20200528022429.32078-1-hpeter+linux_kernel@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-29serial: 8250: Support rs485 bus termination GPIOLukas Wunner
Commit e8759ad17d41 ("serial: uapi: Add support for bus termination") introduced the ability to enable rs485 bus termination from user space. So far the feature is only used by a single driver, 8250_exar.c, using a hardcoded GPIO pin specific to Siemens IOT2040 products. Provide for a more generic solution by allowing specification of an rs485 bus termination GPIO pin in the device tree: Amend the serial core to retrieve the GPIO from the device tree (or ACPI table) and amend the default ->rs485_config() callback for 8250 drivers to change the GPIO on request from user space. Perhaps 8250_exar.c can be converted to the generic approach in a follow-up patch. Signed-off-by: Lukas Wunner <lukas@wunner.de> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Jan Kiszka <jan.kiszka@siemens.com> Link: https://lore.kernel.org/r/94c6c800d1ca9fa04766dd1d43a8272c5ad4bedd.1589811297.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-29serial: 8520_port: Fix function param documentationHeiko Stuebner
The parameter is named p while the documentation talks about up. Fix the doc to be in line with the code. Fixes: 058bc104f7ca ("serial: 8250: Generalize rs485 software emulation") Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200517215610.2131618-2-heiko@sntech.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-27serial: 8250: Enable 16550A variants by default on non-x86Josh Triplett
Some embedded devices still use these serial ports; make sure they're still enabled by default on architectures more likely to have them, to avoid rendering someone's console unavailable. Reported-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reported-by: Maxim Kochetkov <fido_max@inbox.ru> Fixes: dc56ecb81a0a ("serial: 8250: Support disabling mdelay-filled probes of 16550A variants") Cc: stable <stable@vger.kernel.org> Signed-off-by: Josh Triplett <josh@joshtriplett.org> Link: https://lore.kernel.org/r/a20b5fb7dd295cfb48160eecf4bdebd76332d67d.1590509426.git.josh@joshtriplett.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-15serial: 8250: Fix max baud limit in generic 8250 portSerge Semin
Standard 8250 UART ports are designed in a way so they can communicate with baud rates up to 1/16 of a reference frequency. It's expected from most of the currently supported UART controllers. That's why the former version of serial8250_get_baud_rate() method called uart_get_baud_rate() with min and max baud rates passed as (port->uartclk / 16 / UART_DIV_MAX) and ((port->uartclk + tolerance) / 16) respectively. Doing otherwise, like it was suggested in commit ("serial: 8250_mtk: support big baud rate."), caused acceptance of bauds, which was higher than the normal UART controllers actually supported. As a result if some user-space program requested to set a baud greater than (uartclk / 16) it would have been permitted without truncation, but then serial8250_get_divisor(baud) (which calls uart_get_divisor() to get the reference clock divisor) would have returned a zero divisor. Setting zero divisor will cause an unpredictable effect varying from chip to chip. In case of DW APB UART the communications just stop. Lets fix this problem by getting back the limitation of (uartclk + tolerance) / 16 maximum baud supported by the generic 8250 port. Mediatek 8250 UART ports driver developer shouldn't have touched it in the first place notably seeing he already provided a custom version of set_termios() callback in that glue-driver which took into account the extended baud rate values and accordingly updated the standard and vendor-specific divisor latch registers anyway. Fixes: 81bb549fdf14 ("serial: 8250_mtk: support big baud rate.") Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Paul Burton <paulburton@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Long Cheng <long.cheng@mediatek.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Russell King <linux@armlinux.org.uk> Cc: linux-mips@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-mediatek@lists.infradead.org Link: https://lore.kernel.org/r/20200506233136.11842-2-Sergey.Semin@baikalelectronics.ru Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-15serial: Allow uart_get_rs485_mode() to return errnoLukas Wunner
We're about to amend uart_get_rs485_mode() to support a GPIO pin for rs485 bus termination. Retrieving the GPIO descriptor may fail, so allow uart_get_rs485_mode() to return an errno and change all callers to check for failure. The GPIO descriptor is going to be stored in struct uart_port. Pass that struct to uart_get_rs485_mode() in lieu of a struct device and struct serial_rs485, both of which are directly accessible from struct uart_port. A few drivers call uart_get_rs485_mode() before setting the struct device pointer in struct uart_port. Shuffle those calls around where necessary. [Heiko Stuebner did the ar933x_uart.c portion, hence his Signed-off-by.] Signed-off-by: Heiko Stuebner <heiko@sntech.de> Signed-off-by: Lukas Wunner <lukas@wunner.de> Link: https://lore.kernel.org/r/271e814af4b0db3bffbbb74abf2b46b75add4516.1589285873.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-15serial: 8250: Avoid error message on reprobeLukas Wunner
If the call to uart_add_one_port() in serial8250_register_8250_port() fails, a half-initialized entry in the serial_8250ports[] array is left behind. A subsequent reprobe of the same serial port causes that entry to be reused. Because uart->port.dev is set, uart_remove_one_port() is called for the half-initialized entry and bails out with an error message: bcm2835-aux-uart 3f215040.serial: Removing wrong port: (null) != (ptrval) The same happens on failure of mctrl_gpio_init() since commit 4a96895f74c9 ("tty/serial/8250: use mctrl_gpio helpers"). Fix by zeroing the uart->port.dev pointer in the probe error path. The bug was introduced in v2.6.10 by historical commit befff6f5bf5f ("[SERIAL] Add new port registration/unregistration functions."): https://git.kernel.org/tglx/history/c/befff6f5bf5f The commit added an unconditional call to uart_remove_one_port() in serial8250_register_port(). In v3.7, commit 835d844d1a28 ("8250_pnp: do pnp probe before legacy probe") made that call conditional on uart->port.dev which allows me to fix the issue by zeroing that pointer in the error path. Thus, the present commit will fix the problem as far back as v3.7 whereas still older versions need to also cherry-pick 835d844d1a28. Fixes: 835d844d1a28 ("8250_pnp: do pnp probe before legacy probe") Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: stable@vger.kernel.org # v2.6.10 Cc: stable@vger.kernel.org # v2.6.10: 835d844d1a28: 8250_pnp: do pnp probe before legacy Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/b4a072013ee1a1d13ee06b4325afb19bda57ca1b.1589285873.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-15serial: 8250_exar: Make use of PCI_DEVICE_DATA() macroAndy Shevchenko
Since PCI core provides a generic PCI_DEVICE_DATA() macro, replace contents of EXAR_DEVICE() with former one. No functional change intended. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200512140252.67631-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-08serial: 8250_pci: Move Pericom IDs to pci_ids.hKai-Heng Feng
Move the IDs to pci_ids.h so it can be used by next patch. Link: https://lore.kernel.org/r/20200508065343.32751-1-kai.heng.feng@canonical.com Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: stable@vger.kernel.org
2020-04-16drivers/tty: remove redundant assignment to variable i and rename it to retColin Ian King
The variable i is being assigned a value that is never read and it is being updated later with a new value. The assignment is redundant and can be removed. Also rename i to ret as this new name makes makes more sense. Addresses-Coverity: ("Unused value") Signed-off-by: Colin Ian King <colin.king@canonical.com> Acked-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20200405135423.383466-1-colin.king@canonical.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-31Merge tag 'tty-5.7-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial updates from Greg KH: "Here is the big set of TTY / Serial patches for 5.7-rc1 Lots of console fixups and reworking in here, serial core tweaks (doesn't that ever get old, why are we still creating new serial devices?), serial driver updates, line-protocol driver updates, and some vt cleanups and fixes included in here as well. All have been in linux-next with no reported issues" * tag 'tty-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (161 commits) serial: 8250: Optimize irq enable after console write serial: 8250: Fix rs485 delay after console write vt: vt_ioctl: fix use-after-free in vt_in_use() vt: vt_ioctl: fix VT_DISALLOCATE freeing in-use virtual console tty: serial: make SERIAL_SPRD depend on COMMON_CLK tty: serial: fsl_lpuart: fix return value checking tty: serial: fsl_lpuart: move dma_request_chan() ARM: dts: tango4: Make /serial compatible with ns16550a ARM: dts: mmp*: Make the serial ports compatible with xscale-uart ARM: dts: mmp*: Fix serial port names ARM: dts: mmp2-brownstone: Don't redeclare phandle references ARM: dts: pxa*: Make the serial ports compatible with xscale-uart ARM: dts: pxa*: Fix serial port names ARM: dts: pxa*: Don't redeclare phandle references serial: omap: drop unused dt-bindings header serial: 8250: 8250_omap: Add DMA support for UARTs on K3 SoCs serial: 8250: 8250_omap: Work around errata causing spurious IRQs with DMA serial: 8250: 8250_omap: Extend driver data to pass FIFO trigger info serial: 8250: 8250_omap: Move locking out from __dma_rx_do_complete() serial: 8250: 8250_omap: Account for data in flight during DMA teardown ...
2020-03-30Merge branch 'pm-qos'Rafael J. Wysocki
* pm-qos: (30 commits) PM: QoS: annotate data races in pm_qos_*_value() Documentation: power: fix pm_qos_interface.rst format warning PM: QoS: Make CPU latency QoS depend on CONFIG_CPU_IDLE Documentation: PM: QoS: Update to reflect previous code changes PM: QoS: Update file information comments PM: QoS: Drop PM_QOS_CPU_DMA_LATENCY and rename related functions sound: Call cpu_latency_qos_*() instead of pm_qos_*() drivers: usb: Call cpu_latency_qos_*() instead of pm_qos_*() drivers: tty: Call cpu_latency_qos_*() instead of pm_qos_*() drivers: spi: Call cpu_latency_qos_*() instead of pm_qos_*() drivers: net: Call cpu_latency_qos_*() instead of pm_qos_*() drivers: mmc: Call cpu_latency_qos_*() instead of pm_qos_*() drivers: media: Call cpu_latency_qos_*() instead of pm_qos_*() drivers: hsi: Call cpu_latency_qos_*() instead of pm_qos_*() drm: i915: Call cpu_latency_qos_*() instead of pm_qos_*() x86: platform: iosf_mbi: Call cpu_latency_qos_*() instead of pm_qos_*() cpuidle: Call cpu_latency_qos_limit() instead of pm_qos_request() PM: QoS: Add CPU latency QoS API wrappers PM: QoS: Adjust pm_qos_request() signature and reorder pm_qos.h PM: QoS: Simplify definitions of CPU latency QoS trace events ...
2020-03-27serial: 8250: Optimize irq enable after console writeLukas Wunner
Commit 7f9803072ff6 ("serial: 8250: Support console on software emulated rs485 ports") amended serial8250_console_write() with rs485 support, but positioned the invocation of ->rs485_stop_tx() after re-enablement of interrupts. The irq handler and ->console_write() are serialized with the port spinlock, so no problem there, but due to the rs485 delay, the irq handler may unnecessarily spin for a while. Avoid that by moving ->rs485_stop_tx() before re-enablement of interrupts, which also mirrors the order at the beginning of serial8250_console_write(). Signed-off-by: Lukas Wunner <lukas@wunner.de> Link: https://lore.kernel.org/r/019839cb1f61b01210b6ff9ac9f9079ca77f8411.1585319447.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-27serial: 8250: Fix rs485 delay after console writeLukas Wunner
Due to a silly copy-paste mistake, commit 7f9803072ff6 ("serial: 8250: Support console on software emulated rs485 ports") erroneously pauses for the duration of delay_rts_before_send after writing to the console, instead of delay_rts_after_send. Mea culpa. Fixes: 7f9803072ff6 ("serial: 8250: Support console on software emulated rs485 ports") Signed-off-by: Lukas Wunner <lukas@wunner.de> Link: https://lore.kernel.org/r/9dd67f33c90d23f7fafa3b81b1e812ddabf9ca24.1585319447.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-24serial: 8250: 8250_omap: Add DMA support for UARTs on K3 SoCsVignesh Raghavendra
UART on K3 SoCs has configurable RX timeout behavior (controlled via EFR2) and better DMA integration. This allows to transfer as larger amount data per DMA transfer compared to older SoCs. Add support for the same. Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com> Link: https://lore.kernel.org/r/20200319110344.21348-7-vigneshr@ti.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-24serial: 8250: 8250_omap: Work around errata causing spurious IRQs with DMAVignesh Raghavendra
As per Advisory 27 of AM437x Silicon errata document, Spurious UART interrupts may occur when DMA mode (FCR.DMA_MODE) is enabled. The Interrupt Controller flags that a UART interrupt has occurred; however, the associated IT_PENDING bit remains set to 1, indicating that no interrupt is pending. Acknowledge the spurious interrupts for every occurrence as workaround. Errata is applicable to all TI SoCs with this IP. Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com> Link: https://lore.kernel.org/r/20200319110344.21348-6-vigneshr@ti.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-24serial: 8250: 8250_omap: Extend driver data to pass FIFO trigger infoVignesh Raghavendra
Although same 8250 compliant UART IP is reused across different SoC, their integration wrt DMA varies greatly across SoCs. Therefore, different SoC may need to use different FIFO trigger level for DMA event and DMA configuration parameters. Provide a way to pass this information via driver data. This is required to support UART DMA on AM654/J721e SoCs. Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com> Link: https://lore.kernel.org/r/20200319110344.21348-5-vigneshr@ti.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-24serial: 8250: 8250_omap: Move locking out from __dma_rx_do_complete()Peter Ujfalusi
Caller functions of __dma_rx_do_complete() already hold rx_dma_lock. Therefore move locking out of the function to avoid need to release and reacquire lock. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com> Link: https://lore.kernel.org/r/20200319110344.21348-4-vigneshr@ti.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-24serial: 8250: 8250_omap: Account for data in flight during DMA teardownVignesh Raghavendra
Take into account data stuck in DMA internal buffers before pushing data to higher layer. dma_tx_state has "in_flight_bytes" member that provides this information. Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com> Link: https://lore.kernel.org/r/20200319110344.21348-3-vigneshr@ti.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-24serial: 8250: 8250_omap: Terminate DMA before pushing data on RX timeoutVignesh Raghavendra
Terminate and flush DMA internal buffers, before pushing RX data to higher layer. Otherwise, this will lead to data corruption, as driver would end up pushing stale buffer data to higher layer while actual data is still stuck inside DMA hardware and has yet not arrived at the memory. While at that, replace deprecated dmaengine_terminate_all() with dmaengine_terminate_async(). Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com> Link: https://lore.kernel.org/r/20200319110344.21348-2-vigneshr@ti.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-24serial: 8250_omap: Fix sleeping function called from invalid context during ↵Peter Ujfalusi
probe When booting j721e the following bug is printed: [ 1.154821] BUG: sleeping function called from invalid context at kernel/sched/completion.c:99 [ 1.154827] in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 12, name: kworker/0:1 [ 1.154832] 3 locks held by kworker/0:1/12: [ 1.154836] #0: ffff000840030728 ((wq_completion)events){+.+.}, at: process_one_work+0x1d4/0x6e8 [ 1.154852] #1: ffff80001214fdd8 (deferred_probe_work){+.+.}, at: process_one_work+0x1d4/0x6e8 [ 1.154860] #2: ffff00084060b170 (&dev->mutex){....}, at: __device_attach+0x38/0x138 [ 1.154872] irq event stamp: 63096 [ 1.154881] hardirqs last enabled at (63095): [<ffff800010b74318>] _raw_spin_unlock_irqrestore+0x70/0x78 [ 1.154887] hardirqs last disabled at (63096): [<ffff800010b740d8>] _raw_spin_lock_irqsave+0x28/0x80 [ 1.154893] softirqs last enabled at (62254): [<ffff800010080c88>] _stext+0x488/0x564 [ 1.154899] softirqs last disabled at (62247): [<ffff8000100fdb3c>] irq_exit+0x114/0x140 [ 1.154906] CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.6.0-rc6-next-20200318-00094-g45e4089b0bd3 #221 [ 1.154911] Hardware name: Texas Instruments K3 J721E SoC (DT) [ 1.154917] Workqueue: events deferred_probe_work_func [ 1.154923] Call trace: [ 1.154928] dump_backtrace+0x0/0x190 [ 1.154933] show_stack+0x14/0x20 [ 1.154940] dump_stack+0xe0/0x148 [ 1.154946] ___might_sleep+0x150/0x1f0 [ 1.154952] __might_sleep+0x4c/0x80 [ 1.154957] wait_for_completion_timeout+0x40/0x140 [ 1.154964] ti_sci_set_device_state+0xa0/0x158 [ 1.154969] ti_sci_cmd_get_device_exclusive+0x14/0x20 [ 1.154977] ti_sci_dev_start+0x34/0x50 [ 1.154984] genpd_runtime_resume+0x78/0x1f8 [ 1.154991] __rpm_callback+0x3c/0x140 [ 1.154996] rpm_callback+0x20/0x80 [ 1.155001] rpm_resume+0x568/0x758 [ 1.155007] __pm_runtime_resume+0x44/0xb0 [ 1.155013] omap8250_probe+0x2b4/0x508 [ 1.155019] platform_drv_probe+0x50/0xa0 [ 1.155023] really_probe+0xd4/0x318 [ 1.155028] driver_probe_device+0x54/0xe8 [ 1.155033] __device_attach_driver+0x80/0xb8 [ 1.155039] bus_for_each_drv+0x74/0xc0 [ 1.155044] __device_attach+0xdc/0x138 [ 1.155049] device_initial_probe+0x10/0x18 [ 1.155053] bus_probe_device+0x98/0xa0 [ 1.155058] deferred_probe_work_func+0x74/0xb0 [ 1.155063] process_one_work+0x280/0x6e8 [ 1.155068] worker_thread+0x48/0x430 [ 1.155073] kthread+0x108/0x138 [ 1.155079] ret_from_fork+0x10/0x18 To fix the bug we need to first call pm_runtime_enable() prior to any pm_runtime calls. Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Link: https://lore.kernel.org/r/20200320125200.6772-1-peter.ujfalusi@ti.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-24serial: 8250: 8250_omap: Fix throttle to call stop_rx()Vignesh Raghavendra
Call stop_rx() to halt reception when throttle is requested. Update unthrottle callback to restart reception. Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com> Link: https://lore.kernel.org/r/20200319103230.16867-3-vigneshr@ti.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-24serial: 8250_port: Don't service RX FIFO if throttledVignesh Raghavendra
When port's throttle callback is called, it should stop pushing any more data into TTY buffer to avoid buffer overflow. This means driver has to stop HW from receiving more data and assert the HW flow control. For UARTs with auto HW flow control (such as 8250_omap) manual assertion of flow control line is not possible and only way is to allow RX FIFO to fill up, thus trigger auto HW flow control logic. Therefore make sure that 8250 generic IRQ handler does not drain data when port is stopped (i.e UART_LSR_DR is unset in read_status_mask). Not servicing, RX FIFO would trigger auto HW flow control when FIFO occupancy reaches preset threshold, thus halting RX. Since, error conditions in UART_LSR register are cleared just by reading the register, data has to be drained in case there are FIFO errors, else error information will lost. Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com> Link: https://lore.kernel.org/r/20200319103230.16867-2-vigneshr@ti.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-17serial: 8250_port: Disable DMA operations for kernel consoleAndy Shevchenko
It would be too tricky and error prone to allow DMA operations on kernel console. One of the concern is when DMA is a separate device, for example on Intel CherryTrail platforms, and might need special work around to be functional, see the commit eebb3e8d8aaf ("ACPI / LPSS: override power state for LPSS DMA device") for more information. Another one is that kernel console is used in atomic context, e.g. when printing crucial information to the user (Oops or crash), and DMA may not serve due to power management complications including non-atomic ACPI calls but not limited to it (see above). Besides that, other concerns are described in the commit 84b40e3b57ee ("serial: 8250: omap: Disable DMA for console UART") done for OMAP UART and may be repeated here. Disable any kind of DMA operations on kernel console due to above concerns. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200217114016.49856-7-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-17serial: 8250_port: Don't use power management for kernel consoleAndy Shevchenko
Doing any kind of power management for kernel console is really bad idea. First of all, it runs in poll and atomic mode. This fact attaches a limitation on the functions that might be called. For example, pm_runtime_get_sync() might sleep and thus can't be used. This call needs, for example, to bring the device to powered on state on the system, where the power on sequence may require on-atomic operations, such as Intel Cherrytrail with ACPI enumerated UARTs. That said, on ACPI enabled platforms it might even call firmware for a job. On the other hand pm_runtime_get() doesn't guarantee that device will become powered on fast enough. Besides that, imagine the case when console is about to print a kernel Oops and it's powered off. In such an emergency case calling the complex functions is not the best what we can do, taking into consideration that user wants to see at least something of the last kernel word before it passes away. Here we modify the 8250 console code to prevent runtime power management. Note, there is a behaviour change for OMAP boards. It will require to detach kernel console to become idle. Link: https://lists.openwall.net/linux-kernel/2018/09/29/65 Suggested-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200217114016.49856-6-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-10Merge 5.6-rc5 into tty-nextGreg Kroah-Hartman
We need the vt fixes in here and it resolves a merge issue with drivers/tty/vt/selection.c Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-07serial: 8250: Support console on software emulated rs485 portsLukas Wunner
Commit e490c9144cfa ("tty: Add software emulated RS485 support for 8250") introduced support to use RTS as an rs485 Transmit Enable signal if data is transmitted through the tty layer. Console messages bypass the tty layer and instead are emitted via serial8250_console_write(). Amend that function to drive RTS as well, allowing for a console on rs485 ports. Note that serial8250_console_write() may be called concurrently to the tty layer accessing the port. The two protect their accesses with the port lock, but serial8250_console_write() may find RTS still being asserted by the tty layer, in which case it shouldn't be deasserted after the console message has been printed. Recognize such situations by checking the em485->tx_stopped flag. If a delay_rts_before_send or delay_rts_after_send has been specified, serial8250_console_write() busy-waits for its duration. Optimizations for those wait times are conceivable: E.g. if RTS is already asserted, we could check whether em485->start_tx_timer is active and wait only for the remaining expire time. But this would require calling into the hrtimer infrastructure, which involves acquiring locks and potentially reprogramming timer hardware. Such operations seem too risky in the context of console printout, which needs to work even when the kernel has crashed and emits a BUG splat. So I've gone with a simplistic solution which just always waits for the full delay. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Matwey V. Kornilov <matwey@sai.msu.ru> Link: https://lore.kernel.org/r/65edffce4670a19e598015c03cbe46f1ffd93e43.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-07serial: 8250_bcm2835aux: Support rs485 software emulationLukas Wunner
Amend 8250_bcm2835aux.c to support rs485 as introduced for 8250_omap.c by commit e490c9144cfa ("tty: Add software emulated RS485 support for 8250"). The bcm2835aux differs from omap chips by inverting the meaning of RTS in the MCR register: If the bit is clear, RTS is high. With omap, it's apparently the other way round. Moreover, omap achieves half-duplex mode by disabling the UART_IER_RDI interrupt and clearing the RX FIFO when TX stops. This approach doesn't work on bcm2835aux because the UART_LSR_DR bit is set even when UART_IER_RDI is disabled. Consequently, serial8250_handle_irq() invokes serial8250_rx_chars() to empty the FIFO and characters are received even though the user requested half-duplex. Solve by disabling the receiver using the non-standard CNTL register. Cache that register in the driver's private data for performance. Set the private data pointer before calling serial8250_register_8250_port() to prevent a null pointer deref in case one of the rs485 callbacks is invoked immediately after port registration. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Matwey V. Kornilov <matwey@sai.msu.ru> Link: https://lore.kernel.org/r/dd86460e20a8f979b7272a0bde73640312b902b1.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-07serial: 8250: Generalize rs485 software emulationLukas Wunner
Commit e490c9144cfa ("tty: Add software emulated RS485 support for 8250") introduced support to use RTS as an rs485 Transmit Enable signal. So far the only drivers taking advantage of it are 8250_omap.c and 8250_of.c. We're about to make use of the feature in 8250_bcm2835aux.c as well. The bcm2835aux differs from omap chips by inverting the meaning of RTS in the MCR register. Moreover, omap achieves half-duplex mode by disabling the RX interrupt and clearing the RX FIFO when TX stops. The bcm2835aux requires disabling the receiver instead. Support these behavioral differences by generalizing the rs485 emulation: Introduce ->rs485_start_tx() and ->rs485_stop_tx() callbacks in struct uart_8250_port, provide generic implementations containing the existing code and use them as callbacks in 8250_omap.c and 8250_of.c. start_tx_rs485() is idempotent in that it recognizes whether RTS is already asserted. Achieve the same by introducing a tx_stopped flag in struct uart_8250_em485. This may even perform a little better on arches where memory access is faster than mmio access. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Matwey V. Kornilov <matwey@sai.msu.ru> Link: https://lore.kernel.org/r/5ac0464ae4414708e723a1e0d52b0c1b2bd41b9b.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-07serial: 8250: Deduplicate rs485 active_timer assignmentLukas Wunner
When rs485 transmission over an 8250 port stops, __stop_tx() assigns active_timer = NULL before calling __stop_tx_rs485(). That function in turn either assigns active_timer = stop_tx_timer and rearms the timer (in case a delay_rts_after_send needs to be observed) or directly calls __do_stop_tx_rs485(). Move the assignment active_timer = NULL to __stop_tx_rs485() into the branch which directly calls __do_stop_tx_rs485(), thereby avoiding a duplicate assignment and simplifying the code. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Matwey V. Kornilov <matwey@sai.msu.ru> Link: https://lore.kernel.org/r/bca638405550eaf92f0c6060b553b687f35885e0.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-07serial: 8250: Sanitize rs485 config harderLukas Wunner
Amend the generic ->rs485_config() callback to sanitize RTS polarity and zero-fill the padding (in addition to the existing sanitization of the RTS delays). Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Matwey V. Kornilov <matwey@sai.msu.ru> Link: https://lore.kernel.org/r/ff833721bc372d38678f289eb2a44dbf016d5203.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-07serial: 8250: Deduplicate ->rs485_config() callbackLukas Wunner
Commit e490c9144cfa ("tty: Add software emulated RS485 support for 8250") introduced support to use RTS as an rs485 Transmit Enable signal. Drivers opt in to the feature by calling serial8250_em485_init() from their ->rs485_config() callback. So far there are two drivers doing that, 8250_omap.c and 8250_of.c. Both use an identical callback. We're about to add a third user of that callback, therefore deduplicate it and move it to 8250_port.c. Drivers now opt in to rs485 software emulation by assigning the generic serial8250_rs485_config() callback introduced herein to their .rs485_config struct member. This change allows unexporting serial8250_em485_init() and declaring it static. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Matwey V. Kornilov <matwey@sai.msu.ru> Cc: Heiko Schocher <hs@denx.de> Link: https://lore.kernel.org/r/fcef63642dc4eae41ae7842d23747b2bf5d40285.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-07serial: 8250: Support rs485 devicetree propertiesLukas Wunner
Retrieve rs485 devicetree properties on registration of 8250 ports in case they are attached to an rs485 transceiver. If the property "linux,rs485-enabled-at-boot-time" is present, invoke the ->rs485_config() callback to immediately deassert RTS, thereby ceasing control of the bus. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Giulio Benetti <giulio.benetti@micronovasrl.com> Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/5908ea89b7f9da54872d6634b606d83db032297a.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-07serial: 8250: Don't touch RTS modem control while in rs485 modeLukas Wunner
serial8250_do_set_mctrl() currently allows modifying the RTS modem control line even when RTS is used as an rs485 Transmit Enable signal. It is thus possible for user space to interfere with rs485 communication by invoking a TIOCMSET ioctl(). Ignore such change requests and retain the current RTS polarity when in rs485 mode. Note that serial8250_set_mctrl() is always called with port->lock held, so there's no risk that RTS is changed concurrently. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Matwey V. Kornilov <matwey@sai.msu.ru> Link: https://lore.kernel.org/r/b1ce34ca9bc4d7bdc6e9852fcf30b1f4e37c8a80.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-07tty: serial: Use the correct style for SPDX License IdentifierNishad Kamdar
This patch corrects the SPDX License Identifier style in header files related to tty serial drivers. For C header files Documentation/process/license-rules.rst mandates C-like comments (opposed to C source files where C++ style should be used). Changes made by using a script provided by Joe Perches here: https://lkml.org/lkml/2019/2/7/46. Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com> Link: https://lore.kernel.org/r/20200301204517.GA10368@nishad Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-06serial: 8250_lpss: Add ->setup() for Elkhart Lake portsAndy Shevchenko
The ->setup() callback is mandatory for the devices. Provide it for Elkhart Lake UART ports. Note, for time being it's empty, but in the future it might require an additional configuration such as DMA. Reported-by: Raymond Tan <raymond.tan@intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200305130822.36850-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-06serial: 8250-mtk: modify mtk uart power and clock managementChangqi Hu
MTK uart design no need to control uart clock, so we just control bus clock in runtime function. Add uart clock used count to avoid repeatedly switching the clock. Signed-off-by: Changqi Hu <changqi.hu@mediatek.com> Link: https://lore.kernel.org/r/1582707225-26815-1-git-send-email-changqi.hu@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-05serial: 8250_exar: add support for ACCES cardsJay Dolan
Add ACCES VIDs and PIDs that use the Exar chips Signed-off-by: Jay Dolan <jay.dolan@accesio.com> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200305140504.22237-1-jay.dolan@accesio.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-24Merge 5.6-rc3 into tty-nextGreg Kroah-Hartman
We want the tty fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-19serial: 8250_port: Use dev_*() instead of pr_*()Andy Shevchenko
Convert pr_*() calls to dev_*() ones. We have a port, we should use it. Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200217114016.49856-5-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-19serial: 8250_port: Switch to use DEVICE_ATTR_RW()Andy Shevchenko
Move device attributes to DEVICE_ATTR_RW() as that would make things a lot more "obvious" what is happening here. Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200217114016.49856-4-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-19serial: 8250_pxa: avoid autodetecting the port typeLubomir Rintel
If we're unlucky enough that this drivers binds to a mrvl,mmp-uart device on a MMP3, the port type gets detected as 16550A instead of XScale, and it won't work. Other drivers that may bind to the same hardware are 8250_of and, god forbid, serial_pxa. Force the port type, we know it's a PORT_XSCALE. Signed-off-by: Lubomir Rintel <lkundrak@v3.sk> Link: https://lore.kernel.org/r/20200219080130.4334-1-lkundrak@v3.sk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-14drivers: tty: Call cpu_latency_qos_*() instead of pm_qos_*()Rafael J. Wysocki
Call cpu_latency_qos_add/update/remove_request() instead of pm_qos_add/update/remove_request(), respectively, because the latter are going to be dropped. No intentional functional impact. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org> Tested-by: Amit Kucheria <amit.kucheria@linaro.org>
2020-02-13serial: 8250_pci: Replace zero-length array with flexible-array memberGustavo A. R. Silva
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Link: https://lore.kernel.org/r/20200213004426.GA7886@embeddedor.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-13PM: QoS: Rename things related to the CPU latency QoSRafael J. Wysocki
First, rename PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE to PM_QOS_CPU_LATENCY_DEFAULT_VALUE and update all of the code referring to it accordingly. Next, rename cpu_dma_constraints to cpu_latency_constraints, move the definition of it closer to the functions referring to it and update all of them accordingly. [While at it, add a comment to mark the start of the code related to the CPU latency QoS.] Finally, rename the pm_qos_power_*() family of functions and pm_qos_power_fops to cpu_latency_qos_*() and cpu_latency_qos_fops, respectively, and update the definition of cpu_latency_qos_miscdev. [While at it, update the miscdev interface code start comment.] No intentional functional impact. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org> Tested-by: Amit Kucheria <amit.kucheria@linaro.org>
2020-02-12tty/serial: 8250_exar: Replace zero-length array with flexible-array memberGustavo A. R. Silva
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertenly introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Link: https://lore.kernel.org/r/20200212193700.GA29715@embeddedor Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-12serial: 8250: Check UPF_IRQ_SHARED in advanceAndy Shevchenko
The commit 54e53b2e8081 ("tty: serial: 8250: pass IRQ shared flag to UART ports") nicely explained the problem: ---8<---8<--- On some systems IRQ lines between multiple UARTs might be shared. If so, the irqflags have to be configured accordingly. The reason is: The 8250 port startup code performs IRQ tests *before* the IRQ handler for that particular port is registered. This is performed in serial8250_do_startup(). This function checks whether IRQF_SHARED is configured and only then disables the IRQ line while testing. This test is performed upon each open() of the UART device. Imagine two UARTs share the same IRQ line: On is already opened and the IRQ is active. When the second UART is opened, the IRQ line has to be disabled while performing IRQ tests. Otherwise an IRQ might handler might be invoked, but the IRQ itself cannot be handled, because the corresponding handler isn't registered, yet. That's because the 8250 code uses a chain-handler and invokes the corresponding port's IRQ handling routines himself. Unfortunately this IRQF_SHARED flag isn't configured for UARTs probed via device tree even if the IRQs are shared. This way, the actual and shared IRQ line isn't disabled while performing tests and the kernel correctly detects a spurious IRQ. So, adding this flag to the DT probe solves the issue. Note: The UPF_SHARE_IRQ flag is configured unconditionally. Therefore, the IRQF_SHARED flag can be set unconditionally as well. Example stack trace by performing `echo 1 > /dev/ttyS2` on a non-patched system: |irq 85: nobody cared (try booting with the "irqpoll" option) | [...] |handlers: |[<ffff0000080fc628>] irq_default_primary_handler threaded [<ffff00000855fbb8>] serial8250_interrupt |Disabling IRQ #85 ---8<---8<--- But unfortunately didn't fix the root cause. Let's try again here by moving IRQ flag assignment from serial_link_irq_chain() to serial8250_do_startup(). This should fix the similar issue reported for 8250_pnp case. Since this change we don't need to have custom solutions in 8250_aspeed_vuart and 8250_of drivers, thus, drop them. Fixes: 1c2f04937b3e ("serial: 8250: add IRQ trigger support") Reported-by: Li RongQing <lirongqing@baidu.com> Cc: Kurt Kanzenbach <kurt@linutronix.de> Cc: Vikram Pandita <vikram.pandita@ti.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: stable <stable@vger.kernel.org> Acked-by: Kurt Kanzenbach <kurt@linutronix.de> Link: https://lore.kernel.org/r/20200211135559.85960-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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