diff options
| -rw-r--r-- | arch/x86/machine/uart.c | 153 |
1 files changed, 146 insertions, 7 deletions
diff --git a/arch/x86/machine/uart.c b/arch/x86/machine/uart.c index 22d3948f..cdb49a90 100644 --- a/arch/x86/machine/uart.c +++ b/arch/x86/machine/uart.c @@ -13,14 +13,12 @@ * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. - * - * - * TODO Make serial line parameters configurable. */ #include <assert.h> #include <stdint.h> +#include <kern/arg.h> #include <kern/console.h> #include <kern/error.h> #include <kern/init.h> @@ -53,6 +51,8 @@ #define UART_LCR_8BITS 0x03 #define UART_LCR_1S 0x00 #define UART_LCR_NP 0x00 +#define UART_LCR_OP 0x08 +#define UART_LCR_EP 0x18 #define UART_LCR_BEN 0x40 #define UART_LCR_DLAB 0x80 @@ -65,6 +65,19 @@ #define UART_MAX_DEVS 4 +#define UART_SPEED_MAX 115200 +#define UART_SPEED_DEFAULT UART_SPEED_MAX + +enum { + UART_PARITY_NONE, + UART_PARITY_ODD, + UART_PARITY_EVEN, +}; + +#define UART_PARITY_DEFAULT UART_PARITY_NONE + +#define UART_DATA_BITS_DEFAULT 8 + struct uart { struct console console; uint16_t port; @@ -243,27 +256,153 @@ static const struct console_ops uart_console_ops = { }; static void __init +uart_init_default(unsigned int *speed, unsigned int *parity, + unsigned int *data_bits) +{ + *speed = UART_SPEED_DEFAULT; + *parity = UART_PARITY_DEFAULT; + *data_bits = UART_DATA_BITS_DEFAULT; +} + +static int __init +uart_init_check_speed(unsigned int speed) +{ + if (speed > UART_SPEED_MAX) { + return ERROR_INVAL; + } + + return 0; +} + +static int __init +uart_init_convert_parity_char(char c, unsigned int *parity) +{ + switch (c) { + case 'n': + *parity = UART_PARITY_NONE; + break; + case 'o': + *parity = UART_PARITY_ODD; + break; + case 'e': + *parity = UART_PARITY_EVEN; + break; + default: + return ERROR_INVAL; + } + + return 0; +} + +static int __init +uart_init_check_data_bits(unsigned int data_bits) +{ + switch (data_bits) { + case 5 ... 8: + break; + default: + return ERROR_INVAL; + } + + return 0; +} + +static void __init +uart_init_args(const struct uart *uart, const char *arg_str, + unsigned int *speed, unsigned int *parity, + unsigned int *data_bits) +{ + char parity_char; + int ret, error; + + ret = sscanf(arg_str, "%u%c%1u", speed, &parity_char, data_bits); + + if (ret < 1) { + goto set_defaults; + } + + error = uart_init_check_speed(*speed); + + if (error) { + goto set_defaults; + } else if (ret < 2) { + return; + } + + error = uart_init_convert_parity_char(parity_char, parity); + + if (error) { + goto set_defaults; + } else if (ret < 3) { + return; + } + + error = uart_init_check_data_bits(*data_bits); + + if (error) { + goto set_defaults; + } + + return; + +set_defaults: + log_warning("uart%zu: invalid serial configuration, using defaults", + uart_get_id(uart)); + uart_init_default(speed, parity, data_bits); +} + +static void __init uart_init(struct uart *uart, uint16_t port, uint16_t intr) { + unsigned int speed, parity, data_bits; + const char *arg_str; char name[CONSOLE_NAME_SIZE]; + uint16_t divisor; uint8_t byte; + snprintf(name, sizeof(name), "uart%zu", uart_get_id(uart)); + arg_str = arg_value(name); + + uart_init_default(&speed, &parity, &data_bits); + + if (arg_str != NULL) { + uart_init_args(uart, arg_str, &speed, &parity, &data_bits); + } + + log_debug("uart%zu: speed:%u parity:%u data_bits:%u", + uart_get_id(uart), speed, parity, data_bits); + uart->port = port; uart->intr = intr; uart_write(uart, UART_REG_IER, 0); + divisor = UART_SPEED_MAX / speed; + uart_set(uart, UART_REG_LCR, UART_LCR_DLAB); - uart_write(uart, UART_REG_DLH, 0); - uart_write(uart, UART_REG_DLL, 1); + uart_write(uart, UART_REG_DLH, divisor >> 8); + uart_write(uart, UART_REG_DLL, divisor & 0xff); uart_clear(uart, UART_REG_LCR, UART_LCR_DLAB); uart_write(uart, UART_REG_MCR, UART_MCR_AUX2 | UART_MCR_RTS | UART_MCR_DTR); - byte = UART_LCR_8BITS | UART_LCR_NP | UART_LCR_1S; + byte = UART_LCR_1S; + + switch (parity) { + case UART_PARITY_NONE: + byte |= UART_LCR_NP; + break; + case UART_PARITY_ODD: + byte |= UART_LCR_OP; + break; + case UART_PARITY_EVEN: + byte |= UART_LCR_EP; + break; + } + + byte |= (data_bits - 5); uart_write(uart, UART_REG_LCR, byte); - snprintf(name, sizeof(name), "uart%zu", uart_get_id(uart)); console_init(&uart->console, name, &uart_console_ops); console_register(&uart->console); } |