diff options
| -rw-r--r-- | drivers/serial/mpc52xx_uart.c | 145 |
1 files changed, 116 insertions, 29 deletions
diff --git a/drivers/serial/mpc52xx_uart.c b/drivers/serial/mpc52xx_uart.c index 84a35f6..1a88b36 100644 --- a/drivers/serial/mpc52xx_uart.c +++ b/drivers/serial/mpc52xx_uart.c @@ -113,7 +113,9 @@ struct psc_ops { unsigned char (*read_char)(struct uart_port *port); void (*cw_disable_ints)(struct uart_port *port); void (*cw_restore_ints)(struct uart_port *port); - unsigned long (*getuartclk)(void *p); + unsigned int (*set_baudrate)(struct uart_port *port, + struct ktermios *new, + struct ktermios *old); int (*clock)(struct uart_port *port, int enable); int (*fifoc_init)(void); void (*fifoc_uninit)(void); @@ -121,6 +123,16 @@ struct psc_ops { irqreturn_t (*handle_irq)(struct uart_port *port); }; +/* setting the prescaler and divisor reg is common for all chips */ +static inline void mpc52xx_set_divisor(struct mpc52xx_psc __iomem *psc, + u16 prescaler, unsigned int divisor) +{ + /* select prescaler */ + out_be16(&psc->mpc52xx_psc_clock_select, prescaler); + out_8(&psc->ctur, divisor >> 8); + out_8(&psc->ctlr, divisor & 0xff); +} + #ifdef CONFIG_PPC_MPC52xx #define FIFO_52xx(port) ((struct mpc52xx_psc_fifo __iomem *)(PSC(port)+1)) static void mpc52xx_psc_fifo_init(struct uart_port *port) @@ -128,9 +140,6 @@ static void mpc52xx_psc_fifo_init(struct uart_port *port) struct mpc52xx_psc __iomem *psc = PSC(port); struct mpc52xx_psc_fifo __iomem *fifo = FIFO_52xx(port); - /* /32 prescaler */ - out_be16(&psc->mpc52xx_psc_clock_select, 0xdd00); - out_8(&fifo->rfcntl, 0x00); out_be16(&fifo->rfalarm, 0x1ff); out_8(&fifo->tfcntl, 0x07); @@ -219,15 +228,47 @@ static void mpc52xx_psc_cw_restore_ints(struct uart_port *port) out_be16(&PSC(port)->mpc52xx_psc_imr, port->read_status_mask); } -/* Search for bus-frequency property in this node or a parent */ -static unsigned long mpc52xx_getuartclk(void *p) +static unsigned int mpc5200_psc_set_baudrate(struct uart_port *port, + struct ktermios *new, + struct ktermios *old) { - /* - * 5200 UARTs have a / 32 prescaler - * but the generic serial code assumes 16 - * so return ipb freq / 2 - */ - return mpc5xxx_get_bus_frequency(p) / 2; + unsigned int baud; + unsigned int divisor; + + /* The 5200 has a fixed /32 prescaler, uartclk contains the ipb freq */ + baud = uart_get_baud_rate(port, new, old, + port->uartclk / (32 * 0xffff) + 1, + port->uartclk / 32); + divisor = (port->uartclk + 16 * baud) / (32 * baud); + + /* enable the /32 prescaler and set the divisor */ + mpc52xx_set_divisor(PSC(port), 0xdd00, divisor); + return baud; +} + +static unsigned int mpc5200b_psc_set_baudrate(struct uart_port *port, + struct ktermios *new, + struct ktermios *old) +{ + unsigned int baud; + unsigned int divisor; + u16 prescaler; + + /* The 5200B has a selectable /4 or /32 prescaler, uartclk contains the + * ipb freq */ + baud = uart_get_baud_rate(port, new, old, + port->uartclk / (32 * 0xffff) + 1, + port->uartclk / 4); + divisor = (port->uartclk + 2 * baud) / (4 * baud); + + /* select the proper prescaler and set the divisor */ + if (divisor > 0xffff) { + divisor = (divisor + 4) / 8; + prescaler = 0xdd00; /* /32 */ + } else + prescaler = 0xff00; /* /4 */ + mpc52xx_set_divisor(PSC(port), prescaler, divisor); + return baud; } static void mpc52xx_psc_get_irq(struct uart_port *port, struct device_node *np) @@ -258,7 +299,28 @@ static struct psc_ops mpc52xx_psc_ops = { .read_char = mpc52xx_psc_read_char, .cw_disable_ints = mpc52xx_psc_cw_disable_ints, .cw_restore_ints = mpc52xx_psc_cw_restore_ints, - .getuartclk = mpc52xx_getuartclk, + .set_baudrate = mpc5200_psc_set_baudrate, + .get_irq = mpc52xx_psc_get_irq, + .handle_irq = mpc52xx_psc_handle_irq, +}; + +static struct psc_ops mpc5200b_psc_ops = { + .fifo_init = mpc52xx_psc_fifo_init, + .raw_rx_rdy = mpc52xx_psc_raw_rx_rdy, + .raw_tx_rdy = mpc52xx_psc_raw_tx_rdy, + .rx_rdy = mpc52xx_psc_rx_rdy, + .tx_rdy = mpc52xx_psc_tx_rdy, + .tx_empty = mpc52xx_psc_tx_empty, + .stop_rx = mpc52xx_psc_stop_rx, + .start_tx = mpc52xx_psc_start_tx, + .stop_tx = mpc52xx_psc_stop_tx, + .rx_clr_irq = mpc52xx_psc_rx_clr_irq, + .tx_clr_irq = mpc52xx_psc_tx_clr_irq, + .write_char = mpc52xx_psc_write_char, + .read_char = mpc52xx_psc_read_char, + .cw_disable_ints = mpc52xx_psc_cw_disable_ints, + .cw_restore_ints = mpc52xx_psc_cw_restore_ints, + .set_baudrate = mpc5200b_psc_set_baudrate, .get_irq = mpc52xx_psc_get_irq, .handle_irq = mpc52xx_psc_handle_irq, }; @@ -392,9 +454,35 @@ static void mpc512x_psc_cw_restore_ints(struct uart_port *port) out_be32(&FIFO_512x(port)->rximr, port->read_status_mask & 0x7f); } -static unsigned long mpc512x_getuartclk(void *p) +static unsigned int mpc512x_psc_set_baudrate(struct uart_port *port, + struct ktermios *new, + struct ktermios *old) { - return mpc5xxx_get_bus_frequency(p); + unsigned int baud; + unsigned int divisor; + + /* + * The "MPC5121e Microcontroller Reference Manual, Rev. 3" says on + * pg. 30-10 that the chip supports a /32 and a /10 prescaler. + * Furthermore, it states that "After reset, the prescaler by 10 + * for the UART mode is selected", but the reset register value is + * 0x0000 which means a /32 prescaler. This is wrong. + * + * In reality using /32 prescaler doesn't work, as it is not supported! + * Use /16 or /10 prescaler, see "MPC5121e Hardware Design Guide", + * Chapter 4.1 PSC in UART Mode. + * Calculate with a /16 prescaler here. + */ + + /* uartclk contains the ips freq */ + baud = uart_get_baud_rate(port, new, old, + port->uartclk / (16 * 0xffff) + 1, + port->uartclk / 16); + divisor = (port->uartclk + 8 * baud) / (16 * baud); + + /* enable the /16 prescaler and set the divisor */ + mpc52xx_set_divisor(PSC(port), 0xdd00, divisor); + return baud; } /* Init PSC FIFO Controller */ @@ -498,7 +586,7 @@ static struct psc_ops mpc512x_psc_ops = { .read_char = mpc512x_psc_read_char, .cw_disable_ints = mpc512x_psc_cw_disable_ints, .cw_restore_ints = mpc512x_psc_cw_restore_ints, - .getuartclk = mpc512x_getuartclk, + .set_baudrate = mpc512x_psc_set_baudrate, .clock = mpc512x_psc_clock, .fifoc_init = mpc512x_psc_fifoc_init, .fifoc_uninit = mpc512x_psc_fifoc_uninit, @@ -666,8 +754,8 @@ mpc52xx_uart_set_termios(struct uart_port *port, struct ktermios *new, struct mpc52xx_psc __iomem *psc = PSC(port); unsigned long flags; unsigned char mr1, mr2; - unsigned short ctr; - unsigned int j, baud, quot; + unsigned int j; + unsigned int baud; /* Prepare what we're gonna write */ mr1 = 0; @@ -704,16 +792,9 @@ mpc52xx_uart_set_termios(struct uart_port *port, struct ktermios *new, mr2 |= MPC52xx_PSC_MODE_TXCTS; } - baud = uart_get_baud_rate(port, new, old, 0, port->uartclk/16); - quot = uart_get_divisor(port, baud); - ctr = quot & 0xffff; - /* Get the lock */ spin_lock_irqsave(&port->lock, flags); - /* Update the per-port timeout */ - uart_update_timeout(port, new->c_cflag, baud); - /* Do our best to flush TX & RX, so we don't lose anything */ /* But we don't wait indefinitely ! */ j = 5000000; /* Maximum wait */ @@ -737,8 +818,10 @@ mpc52xx_uart_set_termios(struct uart_port *port, struct ktermios *new, out_8(&psc->command, MPC52xx_PSC_SEL_MODE_REG_1); out_8(&psc->mode, mr1); out_8(&psc->mode, mr2); - out_8(&psc->ctur, ctr >> 8); - out_8(&psc->ctlr, ctr & 0xff); + baud = psc_ops->set_baudrate(port, new, old); + + /* Update the per-port timeout */ + uart_update_timeout(port, new->c_cflag, baud); if (UART_ENABLE_MS(port, new->c_cflag)) mpc52xx_uart_enable_ms(port); @@ -1118,7 +1201,7 @@ mpc52xx_console_setup(struct console *co, char *options) return ret; } - uartclk = psc_ops->getuartclk(np); + uartclk = mpc5xxx_get_bus_frequency(np); if (uartclk == 0) { pr_debug("Could not find uart clock frequency!\n"); return -EINVAL; @@ -1201,6 +1284,7 @@ static struct uart_driver mpc52xx_uart_driver = { static struct of_device_id mpc52xx_uart_of_match[] = { #ifdef CONFIG_PPC_MPC52xx + { .compatible = "fsl,mpc5200b-psc-uart", .data = &mpc5200b_psc_ops, }, { .compatible = "fsl,mpc5200-psc-uart", .data = &mpc52xx_psc_ops, }, /* binding used by old lite5200 device trees: */ { .compatible = "mpc5200-psc-uart", .data = &mpc52xx_psc_ops, }, @@ -1233,7 +1317,10 @@ mpc52xx_uart_of_probe(struct of_device *op, const struct of_device_id *match) pr_debug("Found %s assigned to ttyPSC%x\n", mpc52xx_uart_nodes[idx]->full_name, idx); - uartclk = psc_ops->getuartclk(op->dev.of_node); + /* set the uart clock to the input clock of the psc, the different + * prescalers are taken into account in the set_baudrate() methods + * of the respective chip */ + uartclk = mpc5xxx_get_bus_frequency(op->dev.of_node); if (uartclk == 0) { dev_dbg(&op->dev, "Could not find uart clock frequency!\n"); return -EINVAL; |
