diff options
Diffstat (limited to 'drivers/tty/serial/sccnxp.c')
| -rw-r--r-- | drivers/tty/serial/sccnxp.c | 54 |
1 files changed, 46 insertions, 8 deletions
diff --git a/drivers/tty/serial/sccnxp.c b/drivers/tty/serial/sccnxp.c index 339befdd2f4d..68a24a14f6b7 100644 --- a/drivers/tty/serial/sccnxp.c +++ b/drivers/tty/serial/sccnxp.c @@ -12,6 +12,7 @@ #endif #include <linux/clk.h> +#include <linux/delay.h> #include <linux/err.h> #include <linux/module.h> #include <linux/mod_devicetable.h> @@ -47,7 +48,6 @@ # define MR2_STOP1 (7 << 0) # define MR2_STOP2 (0xf << 0) #define SCCNXP_SR_REG (0x01) -#define SCCNXP_CSR_REG SCCNXP_SR_REG # define SR_RXRDY (1 << 0) # define SR_FULL (1 << 1) # define SR_TXRDY (1 << 2) @@ -56,6 +56,8 @@ # define SR_PE (1 << 5) # define SR_FE (1 << 6) # define SR_BRK (1 << 7) +#define SCCNXP_CSR_REG (SCCNXP_SR_REG) +# define CSR_TIMER_MODE (0x0d) #define SCCNXP_CR_REG (0x02) # define CR_RX_ENABLE (1 << 0) # define CR_RX_DISABLE (1 << 1) @@ -82,9 +84,12 @@ # define IMR_RXRDY (1 << 1) # define ISR_TXRDY(x) (1 << ((x * 4) + 0)) # define ISR_RXRDY(x) (1 << ((x * 4) + 1)) +#define SCCNXP_CTPU_REG (0x06) +#define SCCNXP_CTPL_REG (0x07) #define SCCNXP_IPR_REG (0x0d) #define SCCNXP_OPCR_REG SCCNXP_IPR_REG #define SCCNXP_SOP_REG (0x0e) +#define SCCNXP_START_COUNTER_REG SCCNXP_SOP_REG #define SCCNXP_ROP_REG (0x0f) /* Route helpers */ @@ -103,6 +108,8 @@ struct sccnxp_chip { unsigned long freq_max; unsigned int flags; unsigned int fifosize; + /* Time between read/write cycles */ + unsigned int trwd; }; struct sccnxp_port { @@ -137,6 +144,7 @@ static const struct sccnxp_chip sc2681 = { .freq_max = 4000000, .flags = SCCNXP_HAVE_IO, .fifosize = 3, + .trwd = 200, }; static const struct sccnxp_chip sc2691 = { @@ -147,6 +155,7 @@ static const struct sccnxp_chip sc2691 = { .freq_max = 4000000, .flags = 0, .fifosize = 3, + .trwd = 150, }; static const struct sccnxp_chip sc2692 = { @@ -157,6 +166,7 @@ static const struct sccnxp_chip sc2692 = { .freq_max = 4000000, .flags = SCCNXP_HAVE_IO, .fifosize = 3, + .trwd = 30, }; static const struct sccnxp_chip sc2891 = { @@ -167,6 +177,7 @@ static const struct sccnxp_chip sc2891 = { .freq_max = 8000000, .flags = SCCNXP_HAVE_IO | SCCNXP_HAVE_MR0, .fifosize = 16, + .trwd = 27, }; static const struct sccnxp_chip sc2892 = { @@ -177,6 +188,7 @@ static const struct sccnxp_chip sc2892 = { .freq_max = 8000000, .flags = SCCNXP_HAVE_IO | SCCNXP_HAVE_MR0, .fifosize = 16, + .trwd = 17, }; static const struct sccnxp_chip sc28202 = { @@ -187,6 +199,7 @@ static const struct sccnxp_chip sc28202 = { .freq_max = 50000000, .flags = SCCNXP_HAVE_IO | SCCNXP_HAVE_MR0, .fifosize = 256, + .trwd = 10, }; static const struct sccnxp_chip sc68681 = { @@ -197,6 +210,7 @@ static const struct sccnxp_chip sc68681 = { .freq_max = 4000000, .flags = SCCNXP_HAVE_IO, .fifosize = 3, + .trwd = 200, }; static const struct sccnxp_chip sc68692 = { @@ -207,24 +221,36 @@ static const struct sccnxp_chip sc68692 = { .freq_max = 4000000, .flags = SCCNXP_HAVE_IO, .fifosize = 3, + .trwd = 200, }; -static inline u8 sccnxp_read(struct uart_port *port, u8 reg) +static u8 sccnxp_read(struct uart_port *port, u8 reg) { - return readb(port->membase + (reg << port->regshift)); + struct sccnxp_port *s = dev_get_drvdata(port->dev); + u8 ret; + + ret = readb(port->membase + (reg << port->regshift)); + + ndelay(s->chip->trwd); + + return ret; } -static inline void sccnxp_write(struct uart_port *port, u8 reg, u8 v) +static void sccnxp_write(struct uart_port *port, u8 reg, u8 v) { + struct sccnxp_port *s = dev_get_drvdata(port->dev); + writeb(v, port->membase + (reg << port->regshift)); + + ndelay(s->chip->trwd); } -static inline u8 sccnxp_port_read(struct uart_port *port, u8 reg) +static u8 sccnxp_port_read(struct uart_port *port, u8 reg) { return sccnxp_read(port, (port->line << 3) + reg); } -static inline void sccnxp_port_write(struct uart_port *port, u8 reg, u8 v) +static void sccnxp_port_write(struct uart_port *port, u8 reg, u8 v) { sccnxp_write(port, (port->line << 3) + reg, v); } @@ -233,7 +259,7 @@ static int sccnxp_update_best_err(int a, int b, int *besterr) { int err = abs(a - b); - if ((*besterr < 0) || (*besterr > err)) { + if (*besterr > err) { *besterr = err; return 0; } @@ -281,10 +307,22 @@ static const struct { static int sccnxp_set_baud(struct uart_port *port, int baud) { struct sccnxp_port *s = dev_get_drvdata(port->dev); - int div_std, tmp_baud, bestbaud = baud, besterr = -1; + int div_std, tmp_baud, bestbaud = INT_MAX, besterr = INT_MAX; struct sccnxp_chip *chip = s->chip; u8 i, acr = 0, csr = 0, mr0 = 0; + /* Find divisor to load to the timer preset registers */ + div_std = DIV_ROUND_CLOSEST(port->uartclk, 2 * 16 * baud); + if ((div_std >= 2) && (div_std <= 0xffff)) { + bestbaud = DIV_ROUND_CLOSEST(port->uartclk, 2 * 16 * div_std); + sccnxp_update_best_err(baud, bestbaud, &besterr); + csr = CSR_TIMER_MODE; + sccnxp_port_write(port, SCCNXP_CTPU_REG, div_std >> 8); + sccnxp_port_write(port, SCCNXP_CTPL_REG, div_std); + /* Issue start timer/counter command */ + sccnxp_port_read(port, SCCNXP_START_COUNTER_REG); + } + /* Find best baud from table */ for (i = 0; baud_std[i].baud && besterr; i++) { if (baud_std[i].mr0 && !(chip->flags & SCCNXP_HAVE_MR0)) |