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path: root/drivers/tty/serial/sccnxp.c
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Diffstat (limited to 'drivers/tty/serial/sccnxp.c')
-rw-r--r--drivers/tty/serial/sccnxp.c54
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))