diff --git a/drivers/tty/serial/8250/8250_dwlib.c b/drivers/tty/serial/8250/8250_dwlib.c index d1ff3daeb0ba..da330ef46446 100644 --- a/drivers/tty/serial/8250/8250_dwlib.c +++ b/drivers/tty/serial/8250/8250_dwlib.c @@ -3,8 +3,10 @@ #include #include +#include #include #include +#include #include #include #include @@ -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) @@ -28,6 +39,12 @@ #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) @@ -82,9 +99,83 @@ 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); +/* + * 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) { @@ -109,6 +200,9 @@ static int dw8250_rs485_config(struct uart_port *p, struct ktermios *termios, dw8250_writel_ext(p, DW_UART_DE_EN, 1); dw8250_writel_ext(p, DW_UART_RE_EN, 1); } else { + if (termios) + termios->c_cflag &= ~ADDRB; + tcr &= ~DW_UART_TCR_RS485_EN; } @@ -123,6 +217,10 @@ static int dw8250_rs485_config(struct uart_port *p, struct ktermios *termios, dw8250_writel_ext(p, DW_UART_TCR, tcr); + /* Addressing mode can only be set up after TCR */ + if (rs485->flags & SER_RS485_ENABLED) + dw8250_rs485_set_addr(p, rs485, termios); + return 0; } @@ -142,7 +240,8 @@ static bool dw8250_detect_rs485_hw(struct uart_port *p) 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_RTS_AFTER_SEND | SER_RS485_ADDRB | SER_RS485_ADDR_RECV | + SER_RS485_ADDR_DEST, }; void dw8250_setup_port(struct uart_port *p) @@ -155,6 +254,7 @@ 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;