Merge patch series "Add non-coherent DMA support for AX45MP"

Prabhakar <prabhakar.csengg@gmail.com> says:

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

non-coherent DMA support for AX45MP
====================================

On the Andes AX45MP core, cache coherency is a specification option so it
may not be supported. In this case DMA will fail. To get around with this
issue this patch series does the below:

1] Andes alternative ports is implemented as errata which checks if the
IOCP is missing and only then applies to CMO errata. One vendor specific
SBI EXT (ANDES_SBI_EXT_IOCP_SW_WORKAROUND) is implemented as part of
errata.

Below are the configs which Andes port provides (and are selected by
RZ/Five):
      - ERRATA_ANDES
      - ERRATA_ANDES_CMO

OpenSBI patch supporting ANDES_SBI_EXT_IOCP_SW_WORKAROUND SBI is now
part v1.3 release.

2] Andes AX45MP core has a Programmable Physical Memory Attributes (PMA)
block that allows dynamic adjustment of memory attributes in the runtime.
It contains a configurable amount of PMA entries implemented as CSR
registers to control the attributes of memory locations in interest.
OpenSBI configures the PMA regions as required and creates a reserve memory
node and propagates it to the higher boot stack.

Currently OpenSBI (upstream) configures the required PMA region and passes
this a shared DMA pool to Linux.

    reserved-memory {
        #address-cells = <2>;
        #size-cells = <2>;
        ranges;

        pma_resv0@58000000 {
            compatible = "shared-dma-pool";
            reg = <0x0 0x58000000 0x0 0x08000000>;
            no-map;
            linux,dma-default;
        };
    };

The above shared DMA pool gets appended to Linux DTB so the DMA memory
requests go through this region.

3] We provide callbacks to synchronize specific content between memory and
cache.

4] RZ/Five SoC selects the below configs
        - AX45MP_L2_CACHE
        - DMA_GLOBAL_POOL
        - ERRATA_ANDES
        - ERRATA_ANDES_CMO

----------x---------------------x--------------------x---------------x----

* b4-shazam-merge:
  soc: renesas: Kconfig: Select the required configs for RZ/Five SoC
  cache: Add L2 cache management for Andes AX45MP RISC-V core
  dt-bindings: cache: andestech,ax45mp-cache: Add DT binding documentation for L2 cache controller
  riscv: mm: dma-noncoherent: nonstandard cache operations support
  riscv: errata: Add Andes alternative ports
  riscv: asm: vendorid_list: Add Andes Technology to the vendors list

Link: https://lore.kernel.org/r/20230818135723.80612-1-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

6 files changed, 234 insertions, 0 deletions

diff --git a/drivers/Kconfig b/drivers/Kconfig
index 496ca02ee18f..efb66e25fa2d 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -15,6 +15,8 @@ source "drivers/base/Kconfig"
 
 source "drivers/bus/Kconfig"
 
+source "drivers/cache/Kconfig"
+
 source "drivers/connector/Kconfig"
 
 source "drivers/firmware/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index 0957f63ecb42..cb0afca2e4a0 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -11,6 +11,7 @@ ifdef building_out_of_srctree
 MAKEFLAGS += --include-dir=$(srctree)
 endif
 
+obj-y				+= cache/
 obj-y				+= irqchip/
 obj-y				+= bus/
 
diff --git a/drivers/cache/Kconfig b/drivers/cache/Kconfig
new file mode 100644
index 000000000000..a57677f908f3
--- /dev/null
+++ b/drivers/cache/Kconfig
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0
+menu "Cache Drivers"
+
+config AX45MP_L2_CACHE
+	bool "Andes Technology AX45MP L2 Cache controller"
+	depends on RISCV_DMA_NONCOHERENT
+	select RISCV_NONSTANDARD_CACHE_OPS
+	help
+	  Support for the L2 cache controller on Andes Technology AX45MP platforms.
+
+endmenu
diff --git a/drivers/cache/Makefile b/drivers/cache/Makefile
new file mode 100644
index 000000000000..2012e7fb978d
--- /dev/null
+++ b/drivers/cache/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_AX45MP_L2_CACHE) += ax45mp_cache.o
diff --git a/drivers/cache/ax45mp_cache.c b/drivers/cache/ax45mp_cache.c
new file mode 100644
index 000000000000..57186c58dc84
--- /dev/null
+++ b/drivers/cache/ax45mp_cache.c
@@ -0,0 +1,213 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * non-coherent cache functions for Andes AX45MP
+ *
+ * Copyright (C) 2023 Renesas Electronics Corp.
+ */
+
+#include <linux/cacheflush.h>
+#include <linux/cacheinfo.h>
+#include <linux/dma-direction.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+
+#include <asm/dma-noncoherent.h>
+
+/* L2 cache registers */
+#define AX45MP_L2C_REG_CTL_OFFSET		0x8
+
+#define AX45MP_L2C_REG_C0_CMD_OFFSET		0x40
+#define AX45MP_L2C_REG_C0_ACC_OFFSET		0x48
+#define AX45MP_L2C_REG_STATUS_OFFSET		0x80
+
+/* D-cache operation */
+#define AX45MP_CCTL_L1D_VA_INVAL		0 /* Invalidate an L1 cache entry */
+#define AX45MP_CCTL_L1D_VA_WB			1 /* Write-back an L1 cache entry */
+
+/* L2 CCTL status */
+#define AX45MP_CCTL_L2_STATUS_IDLE		0
+
+/* L2 CCTL status cores mask */
+#define AX45MP_CCTL_L2_STATUS_C0_MASK		0xf
+
+/* L2 cache operation */
+#define AX45MP_CCTL_L2_PA_INVAL			0x8 /* Invalidate an L2 cache entry */
+#define AX45MP_CCTL_L2_PA_WB			0x9 /* Write-back an L2 cache entry */
+
+#define AX45MP_L2C_REG_PER_CORE_OFFSET		0x10
+#define AX45MP_CCTL_L2_STATUS_PER_CORE_OFFSET	4
+
+#define AX45MP_L2C_REG_CN_CMD_OFFSET(n)	\
+	(AX45MP_L2C_REG_C0_CMD_OFFSET + ((n) * AX45MP_L2C_REG_PER_CORE_OFFSET))
+#define AX45MP_L2C_REG_CN_ACC_OFFSET(n)	\
+	(AX45MP_L2C_REG_C0_ACC_OFFSET + ((n) * AX45MP_L2C_REG_PER_CORE_OFFSET))
+#define AX45MP_CCTL_L2_STATUS_CN_MASK(n)	\
+	(AX45MP_CCTL_L2_STATUS_C0_MASK << ((n) * AX45MP_CCTL_L2_STATUS_PER_CORE_OFFSET))
+
+#define AX45MP_CCTL_REG_UCCTLBEGINADDR_NUM	0x80b
+#define AX45MP_CCTL_REG_UCCTLCOMMAND_NUM	0x80c
+
+#define AX45MP_CACHE_LINE_SIZE			64
+
+struct ax45mp_priv {
+	void __iomem *l2c_base;
+	u32 ax45mp_cache_line_size;
+};
+
+static struct ax45mp_priv ax45mp_priv;
+
+/* L2 Cache operations */
+static inline uint32_t ax45mp_cpu_l2c_get_cctl_status(void)
+{
+	return readl(ax45mp_priv.l2c_base + AX45MP_L2C_REG_STATUS_OFFSET);
+}
+
+static void ax45mp_cpu_cache_operation(unsigned long start, unsigned long end,
+				       unsigned int l1_op, unsigned int l2_op)
+{
+	unsigned long line_size = ax45mp_priv.ax45mp_cache_line_size;
+	void __iomem *base = ax45mp_priv.l2c_base;
+	int mhartid = smp_processor_id();
+	unsigned long pa;
+
+	while (end > start) {
+		csr_write(AX45MP_CCTL_REG_UCCTLBEGINADDR_NUM, start);
+		csr_write(AX45MP_CCTL_REG_UCCTLCOMMAND_NUM, l1_op);
+
+		pa = virt_to_phys((void *)start);
+		writel(pa, base + AX45MP_L2C_REG_CN_ACC_OFFSET(mhartid));
+		writel(l2_op, base + AX45MP_L2C_REG_CN_CMD_OFFSET(mhartid));
+		while ((ax45mp_cpu_l2c_get_cctl_status() &
+			AX45MP_CCTL_L2_STATUS_CN_MASK(mhartid)) !=
+			AX45MP_CCTL_L2_STATUS_IDLE)
+			;
+
+		start += line_size;
+	}
+}
+
+/* Write-back L1 and L2 cache entry */
+static inline void ax45mp_cpu_dcache_wb_range(unsigned long start, unsigned long end)
+{
+	ax45mp_cpu_cache_operation(start, end, AX45MP_CCTL_L1D_VA_WB,
+				   AX45MP_CCTL_L2_PA_WB);
+}
+
+/* Invalidate the L1 and L2 cache entry */
+static inline void ax45mp_cpu_dcache_inval_range(unsigned long start, unsigned long end)
+{
+	ax45mp_cpu_cache_operation(start, end, AX45MP_CCTL_L1D_VA_INVAL,
+				   AX45MP_CCTL_L2_PA_INVAL);
+}
+
+static void ax45mp_dma_cache_inv(phys_addr_t paddr, size_t size)
+{
+	unsigned long start = (unsigned long)phys_to_virt(paddr);
+	unsigned long end = start + size;
+	unsigned long line_size;
+	unsigned long flags;
+
+	if (unlikely(start == end))
+		return;
+
+	line_size = ax45mp_priv.ax45mp_cache_line_size;
+
+	start = start & (~(line_size - 1));
+	end = ((end + line_size - 1) & (~(line_size - 1)));
+
+	local_irq_save(flags);
+
+	ax45mp_cpu_dcache_inval_range(start, end);
+
+	local_irq_restore(flags);
+}
+
+static void ax45mp_dma_cache_wback(phys_addr_t paddr, size_t size)
+{
+	unsigned long start = (unsigned long)phys_to_virt(paddr);
+	unsigned long end = start + size;
+	unsigned long line_size;
+	unsigned long flags;
+
+	line_size = ax45mp_priv.ax45mp_cache_line_size;
+	start = start & (~(line_size - 1));
+	local_irq_save(flags);
+	ax45mp_cpu_dcache_wb_range(start, end);
+	local_irq_restore(flags);
+}
+
+static void ax45mp_dma_cache_wback_inv(phys_addr_t paddr, size_t size)
+{
+	ax45mp_dma_cache_wback(paddr, size);
+	ax45mp_dma_cache_inv(paddr, size);
+}
+
+static int ax45mp_get_l2_line_size(struct device_node *np)
+{
+	int ret;
+
+	ret = of_property_read_u32(np, "cache-line-size", &ax45mp_priv.ax45mp_cache_line_size);
+	if (ret) {
+		pr_err("Failed to get cache-line-size, defaulting to 64 bytes\n");
+		return ret;
+	}
+
+	if (ax45mp_priv.ax45mp_cache_line_size != AX45MP_CACHE_LINE_SIZE) {
+		pr_err("Expected cache-line-size to be 64 bytes (found:%u)\n",
+		       ax45mp_priv.ax45mp_cache_line_size);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct riscv_nonstd_cache_ops ax45mp_cmo_ops __initdata = {
+	.wback = &ax45mp_dma_cache_wback,
+	.inv = &ax45mp_dma_cache_inv,
+	.wback_inv = &ax45mp_dma_cache_wback_inv,
+};
+
+static const struct of_device_id ax45mp_cache_ids[] = {
+	{ .compatible = "andestech,ax45mp-cache" },
+	{ /* sentinel */ }
+};
+
+static int __init ax45mp_cache_init(void)
+{
+	struct device_node *np;
+	struct resource res;
+	int ret;
+
+	np = of_find_matching_node(NULL, ax45mp_cache_ids);
+	if (!of_device_is_available(np))
+		return -ENODEV;
+
+	ret = of_address_to_resource(np, 0, &res);
+	if (ret)
+		return ret;
+
+	/*
+	 * If IOCP is present on the Andes AX45MP core riscv_cbom_block_size
+	 * will be 0 for sure, so we can definitely rely on it. If
+	 * riscv_cbom_block_size = 0 we don't need to handle CMO using SW any
+	 * more so we just return success here and only if its being set we
+	 * continue further in the probe path.
+	 */
+	if (!riscv_cbom_block_size)
+		return 0;
+
+	ax45mp_priv.l2c_base = ioremap(res.start, resource_size(&res));
+	if (!ax45mp_priv.l2c_base)
+		return -ENOMEM;
+
+	ret = ax45mp_get_l2_line_size(np);
+	if (ret) {
+		iounmap(ax45mp_priv.l2c_base);
+		return ret;
+	}
+
+	riscv_noncoherent_register_cache_ops(&ax45mp_cmo_ops);
+
+	return 0;
+}
+early_initcall(ax45mp_cache_init);
diff --git a/drivers/soc/renesas/Kconfig b/drivers/soc/renesas/Kconfig
index de31589ed054..67604f24973e 100644
--- a/drivers/soc/renesas/Kconfig
+++ b/drivers/soc/renesas/Kconfig
@@ -334,6 +334,10 @@ if RISCV
 config ARCH_R9A07G043
 	bool "RISC-V Platform support for RZ/Five"
 	select ARCH_RZG2L
+	select AX45MP_L2_CACHE
+	select DMA_GLOBAL_POOL
+	select ERRATA_ANDES
+	select ERRATA_ANDES_CMO
 	help
 	  This enables support for the Renesas RZ/Five SoC.