diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_dwlib.c')
| -rw-r--r-- | drivers/tty/serial/8250/8250_dwlib.c | 152 |
1 files changed, 122 insertions, 30 deletions
diff --git a/drivers/tty/serial/8250/8250_dwlib.c b/drivers/tty/serial/8250/8250_dwlib.c index fbabfdd8c7b8..dbe4d44f60d4 100644 --- a/drivers/tty/serial/8250/8250_dwlib.c +++ b/drivers/tty/serial/8250/8250_dwlib.c @@ -3,8 +3,10 @@ #include <linux/bitops.h> #include <linux/bitfield.h> +#include <linux/delay.h> #include <linux/device.h> #include <linux/kernel.h> +#include <linux/math.h> #include <linux/property.h> #include <linux/serial_8250.h> #include <linux/serial_core.h> @@ -16,9 +18,18 @@ #define DW_UART_DE_EN 0xb0 /* Driver Output Enable Register */ #define DW_UART_RE_EN 0xb4 /* Receiver Output Enable Register */ #define DW_UART_DLF 0xc0 /* Divisor Latch Fraction Register */ +#define DW_UART_RAR 0xc4 /* Receive Address Register */ +#define DW_UART_TAR 0xc8 /* Transmit Address Register */ +#define DW_UART_LCR_EXT 0xcc /* Line Extended Control Register */ #define DW_UART_CPR 0xf4 /* Component Parameter Register */ #define DW_UART_UCV 0xf8 /* UART Component Version */ +/* Receive / Transmit Address Register bits */ +#define DW_UART_ADDR_MASK GENMASK(7, 0) + +/* Line Status Register bits */ +#define DW_UART_LSR_ADDR_RCVD BIT(8) + /* Transceiver Control Register bits */ #define DW_UART_TCR_RS485_EN BIT(0) #define DW_UART_TCR_RE_POL BIT(1) @@ -28,22 +39,28 @@ #define DW_UART_TCR_XFER_MODE_SW_DE_OR_RE FIELD_PREP(DW_UART_TCR_XFER_MODE, 1) #define DW_UART_TCR_XFER_MODE_DE_OR_RE FIELD_PREP(DW_UART_TCR_XFER_MODE, 2) +/* Line Extended Control Register bits */ +#define DW_UART_LCR_EXT_DLS_E BIT(0) +#define DW_UART_LCR_EXT_ADDR_MATCH BIT(1) +#define DW_UART_LCR_EXT_SEND_ADDR BIT(2) +#define DW_UART_LCR_EXT_TRANSMIT_MODE BIT(3) + /* Component Parameter Register bits */ -#define DW_UART_CPR_ABP_DATA_WIDTH (3 << 0) -#define DW_UART_CPR_AFCE_MODE (1 << 4) -#define DW_UART_CPR_THRE_MODE (1 << 5) -#define DW_UART_CPR_SIR_MODE (1 << 6) -#define DW_UART_CPR_SIR_LP_MODE (1 << 7) -#define DW_UART_CPR_ADDITIONAL_FEATURES (1 << 8) -#define DW_UART_CPR_FIFO_ACCESS (1 << 9) -#define DW_UART_CPR_FIFO_STAT (1 << 10) -#define DW_UART_CPR_SHADOW (1 << 11) -#define DW_UART_CPR_ENCODED_PARMS (1 << 12) -#define DW_UART_CPR_DMA_EXTRA (1 << 13) -#define DW_UART_CPR_FIFO_MODE (0xff << 16) +#define DW_UART_CPR_ABP_DATA_WIDTH GENMASK(1, 0) +#define DW_UART_CPR_AFCE_MODE BIT(4) +#define DW_UART_CPR_THRE_MODE BIT(5) +#define DW_UART_CPR_SIR_MODE BIT(6) +#define DW_UART_CPR_SIR_LP_MODE BIT(7) +#define DW_UART_CPR_ADDITIONAL_FEATURES BIT(8) +#define DW_UART_CPR_FIFO_ACCESS BIT(9) +#define DW_UART_CPR_FIFO_STAT BIT(10) +#define DW_UART_CPR_SHADOW BIT(11) +#define DW_UART_CPR_ENCODED_PARMS BIT(12) +#define DW_UART_CPR_DMA_EXTRA BIT(13) +#define DW_UART_CPR_FIFO_MODE GENMASK(23, 16) /* Helper for FIFO size calculation */ -#define DW_UART_CPR_FIFO_SIZE(a) (((a >> 16) & 0xff) * 16) +#define DW_UART_CPR_FIFO_SIZE(a) (FIELD_GET(DW_UART_CPR_FIFO_MODE, (a)) * 16) /* * divisor = div(I) + div(F) @@ -82,10 +99,85 @@ void dw8250_do_set_termios(struct uart_port *p, struct ktermios *termios, struct p->status |= UPSTAT_AUTOCTS; serial8250_do_set_termios(p, termios, old); + + /* Filter addresses which have 9th bit set */ + p->ignore_status_mask |= DW_UART_LSR_ADDR_RCVD; + p->read_status_mask |= DW_UART_LSR_ADDR_RCVD; } EXPORT_SYMBOL_GPL(dw8250_do_set_termios); -static int dw8250_rs485_config(struct uart_port *p, struct serial_rs485 *rs485) +/* + * Wait until re is de-asserted for sure. An ongoing receive will keep + * re asserted until end of frame. Without BUSY indication available, + * only available course of action is to wait for the time it takes to + * receive one frame (there might nothing to receive but w/o BUSY the + * driver cannot know). + */ +static void dw8250_wait_re_deassert(struct uart_port *p) +{ + ndelay(p->frame_time); +} + +static void dw8250_update_rar(struct uart_port *p, u32 addr) +{ + u32 re_en = dw8250_readl_ext(p, DW_UART_RE_EN); + + /* + * RAR shouldn't be changed while receiving. Thus, de-assert RE_EN + * if asserted and wait. + */ + if (re_en) + dw8250_writel_ext(p, DW_UART_RE_EN, 0); + dw8250_wait_re_deassert(p); + dw8250_writel_ext(p, DW_UART_RAR, addr); + if (re_en) + dw8250_writel_ext(p, DW_UART_RE_EN, re_en); +} + +static void dw8250_rs485_set_addr(struct uart_port *p, struct serial_rs485 *rs485, + struct ktermios *termios) +{ + u32 lcr = dw8250_readl_ext(p, DW_UART_LCR_EXT); + + if (rs485->flags & SER_RS485_ADDRB) { + lcr |= DW_UART_LCR_EXT_DLS_E; + if (termios) + termios->c_cflag |= ADDRB; + + if (rs485->flags & SER_RS485_ADDR_RECV) { + u32 delta = p->rs485.flags ^ rs485->flags; + + /* + * rs485 (param) is equal to uart_port's rs485 only during init + * (during init, delta is not yet applicable). + */ + if (unlikely(&p->rs485 == rs485)) + delta = rs485->flags; + + if ((delta & SER_RS485_ADDR_RECV) || + (p->rs485.addr_recv != rs485->addr_recv)) + dw8250_update_rar(p, rs485->addr_recv); + lcr |= DW_UART_LCR_EXT_ADDR_MATCH; + } else { + lcr &= ~DW_UART_LCR_EXT_ADDR_MATCH; + } + if (rs485->flags & SER_RS485_ADDR_DEST) { + /* + * Don't skip writes here as another endpoint could + * have changed communication line's destination + * address in between. + */ + dw8250_writel_ext(p, DW_UART_TAR, rs485->addr_dest); + lcr |= DW_UART_LCR_EXT_SEND_ADDR; + } + } else { + lcr = 0; + } + dw8250_writel_ext(p, DW_UART_LCR_EXT, lcr); +} + +static int dw8250_rs485_config(struct uart_port *p, struct ktermios *termios, + struct serial_rs485 *rs485) { u32 tcr; @@ -93,25 +185,17 @@ static int dw8250_rs485_config(struct uart_port *p, struct serial_rs485 *rs485) tcr &= ~DW_UART_TCR_XFER_MODE; if (rs485->flags & SER_RS485_ENABLED) { - /* Clear unsupported flags. */ - rs485->flags &= SER_RS485_ENABLED | SER_RS485_RX_DURING_TX | - SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND; tcr |= DW_UART_TCR_RS485_EN; - if (rs485->flags & SER_RS485_RX_DURING_TX) { + if (rs485->flags & SER_RS485_RX_DURING_TX) tcr |= DW_UART_TCR_XFER_MODE_DE_DURING_RE; - } else { - /* HW does not support same DE level for tx and rx */ - if (!(rs485->flags & SER_RS485_RTS_ON_SEND) == - !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) - return -EINVAL; - + else tcr |= DW_UART_TCR_XFER_MODE_DE_OR_RE; - } dw8250_writel_ext(p, DW_UART_DE_EN, 1); dw8250_writel_ext(p, DW_UART_RE_EN, 1); } else { - rs485->flags = 0; + if (termios) + termios->c_cflag &= ~ADDRB; tcr &= ~DW_UART_TCR_RS485_EN; } @@ -127,10 +211,9 @@ static int dw8250_rs485_config(struct uart_port *p, struct serial_rs485 *rs485) dw8250_writel_ext(p, DW_UART_TCR, tcr); - rs485->delay_rts_before_send = 0; - rs485->delay_rts_after_send = 0; - - p->rs485 = *rs485; + /* Addressing mode can only be set up after TCR */ + if (rs485->flags & SER_RS485_ENABLED) + dw8250_rs485_set_addr(p, rs485, termios); return 0; } @@ -149,6 +232,12 @@ static bool dw8250_detect_rs485_hw(struct uart_port *p) return reg; } +static const struct serial_rs485 dw8250_rs485_supported = { + .flags = SER_RS485_ENABLED | SER_RS485_RX_DURING_TX | SER_RS485_RTS_ON_SEND | + SER_RS485_RTS_AFTER_SEND | SER_RS485_ADDRB | SER_RS485_ADDR_RECV | + SER_RS485_ADDR_DEST, +}; + void dw8250_setup_port(struct uart_port *p) { struct dw8250_port_data *pd = p->private_data; @@ -159,8 +248,11 @@ void dw8250_setup_port(struct uart_port *p) pd->hw_rs485_support = dw8250_detect_rs485_hw(p); if (pd->hw_rs485_support) { p->rs485_config = dw8250_rs485_config; + up->lsr_save_mask = LSR_SAVE_FLAGS | DW_UART_LSR_ADDR_RCVD; + p->rs485_supported = dw8250_rs485_supported; } else { p->rs485_config = serial8250_em485_config; + p->rs485_supported = serial8250_em485_supported; up->rs485_start_tx = serial8250_em485_start_tx; up->rs485_stop_tx = serial8250_em485_stop_tx; } |