diff options
author | Stephen Boyd <sboyd@codeaurora.org> | 2013-07-24 18:37:30 (GMT) |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-07-26 23:13:29 (GMT) |
commit | 6909dadd914259f459828b11c378ddea08d40ab6 (patch) | |
tree | 396af77914babdd211843fc976f2011918d7e955 /drivers/tty/serial/msm_serial.c | |
parent | f8fb952fd409a4c854a66473c11d35b4e5e9c2eb (diff) | |
download | linux-fsl-qoriq-6909dadd914259f459828b11c378ddea08d40ab6.tar.xz |
msm_serial: Make baud_code detection more dynamic
Currently msm_set_baud_rate() assumes the uart clock rate is
1.8432 MHz. This is not always true, and limits our options to
program the baud rate. Instead of assuming the rate and
hard-coding the baud_code based on it, calculate the divider that
we want and try to find the closest baud_code that matches. This
allows us to support uarts with faster clock speeds.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/msm_serial.c')
-rw-r--r-- | drivers/tty/serial/msm_serial.c | 98 |
1 files changed, 44 insertions, 54 deletions
diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c index 4184c51..ca2ae65 100644 --- a/drivers/tty/serial/msm_serial.c +++ b/drivers/tty/serial/msm_serial.c @@ -322,70 +322,60 @@ static void msm_break_ctl(struct uart_port *port, int break_ctl) msm_write(port, UART_CR_CMD_STOP_BREAK, UART_CR); } +struct msm_baud_map { + u16 divisor; + u8 code; + u8 rxstale; +}; + +static const struct msm_baud_map * +msm_find_best_baud(struct uart_port *port, unsigned int baud) +{ + unsigned int i, divisor; + const struct msm_baud_map *entry; + static const struct msm_baud_map table[] = { + { 1536, 0x00, 1 }, + { 768, 0x11, 1 }, + { 384, 0x22, 1 }, + { 192, 0x33, 1 }, + { 96, 0x44, 1 }, + { 48, 0x55, 1 }, + { 32, 0x66, 1 }, + { 24, 0x77, 1 }, + { 16, 0x88, 1 }, + { 12, 0x99, 6 }, + { 8, 0xaa, 6 }, + { 6, 0xbb, 6 }, + { 4, 0xcc, 6 }, + { 3, 0xdd, 8 }, + { 2, 0xee, 16 }, + { 1, 0xff, 31 }, + }; + + divisor = uart_get_divisor(port, baud); + + for (i = 0, entry = table; i < ARRAY_SIZE(table); i++, entry++) + if (entry->divisor <= divisor) + break; + + return entry; /* Default to smallest divider */ +} + static int msm_set_baud_rate(struct uart_port *port, unsigned int baud) { - unsigned int baud_code, rxstale, watermark; + unsigned int rxstale, watermark; struct msm_port *msm_port = UART_TO_MSM(port); + const struct msm_baud_map *entry; - switch (baud) { - case 300: - baud_code = UART_CSR_300; - rxstale = 1; - break; - case 600: - baud_code = UART_CSR_600; - rxstale = 1; - break; - case 1200: - baud_code = UART_CSR_1200; - rxstale = 1; - break; - case 2400: - baud_code = UART_CSR_2400; - rxstale = 1; - break; - case 4800: - baud_code = UART_CSR_4800; - rxstale = 1; - break; - case 9600: - baud_code = UART_CSR_9600; - rxstale = 2; - break; - case 14400: - baud_code = UART_CSR_14400; - rxstale = 3; - break; - case 19200: - baud_code = UART_CSR_19200; - rxstale = 4; - break; - case 28800: - baud_code = UART_CSR_28800; - rxstale = 6; - break; - case 38400: - baud_code = UART_CSR_38400; - rxstale = 8; - break; - case 57600: - baud_code = UART_CSR_57600; - rxstale = 16; - break; - case 115200: - default: - baud_code = UART_CSR_115200; - baud = 115200; - rxstale = 31; - break; - } + entry = msm_find_best_baud(port, baud); if (msm_port->is_uartdm) msm_write(port, UART_CR_CMD_RESET_RX, UART_CR); - msm_write(port, baud_code, UART_CSR); + msm_write(port, entry->code, UART_CSR); /* RX stale watermark */ + rxstale = entry->rxstale; watermark = UART_IPR_STALE_LSB & rxstale; watermark |= UART_IPR_RXSTALE_LAST; watermark |= UART_IPR_STALE_TIMEOUT_MSB & (rxstale << 2); |