| 1 | --- a/drivers/tty/serial/ar933x_uart.c |
| 2 | +++ b/drivers/tty/serial/ar933x_uart.c |
| 3 | @@ -25,11 +25,19 @@ |
| 4 | #include <linux/io.h> |
| 5 | #include <linux/irq.h> |
| 6 | |
| 7 | +#include <asm/div64.h> |
| 8 | + |
| 9 | #include <asm/mach-ath79/ar933x_uart.h> |
| 10 | #include <asm/mach-ath79/ar933x_uart_platform.h> |
| 11 | |
| 12 | #define DRIVER_NAME "ar933x-uart" |
| 13 | |
| 14 | +#define AR933X_UART_MAX_SCALE 0xff |
| 15 | +#define AR933X_UART_MAX_STEP 0xffff |
| 16 | + |
| 17 | +#define AR933X_UART_MIN_BAUD 300 |
| 18 | +#define AR933X_UART_MAX_BAUD 3000000 |
| 19 | + |
| 20 | #define AR933X_DUMMY_STATUS_RD 0x01 |
| 21 | |
| 22 | static struct uart_driver ar933x_uart_driver; |
| 23 | @@ -37,6 +45,8 @@ static struct uart_driver ar933x_uart_dr |
| 24 | struct ar933x_uart_port { |
| 25 | struct uart_port port; |
| 26 | unsigned int ier; /* shadow Interrupt Enable Register */ |
| 27 | + unsigned int min_baud; |
| 28 | + unsigned int max_baud; |
| 29 | }; |
| 30 | |
| 31 | static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up, |
| 32 | @@ -162,6 +172,57 @@ static void ar933x_uart_enable_ms(struct |
| 33 | { |
| 34 | } |
| 35 | |
| 36 | +/* |
| 37 | + * baudrate = (clk / (scale + 1)) * (step * (1 / 2^17)) |
| 38 | + */ |
| 39 | +static unsigned long ar933x_uart_get_baud(unsigned int clk, |
| 40 | + unsigned int scale, |
| 41 | + unsigned int step) |
| 42 | +{ |
| 43 | + u64 t; |
| 44 | + u32 div; |
| 45 | + |
| 46 | + div = (2 << 16) * (scale + 1); |
| 47 | + t = clk; |
| 48 | + t *= step; |
| 49 | + t += (div / 2); |
| 50 | + do_div(t, div); |
| 51 | + |
| 52 | + return t; |
| 53 | +} |
| 54 | + |
| 55 | +static void ar933x_uart_get_scale_step(unsigned int clk, |
| 56 | + unsigned int baud, |
| 57 | + unsigned int *scale, |
| 58 | + unsigned int *step) |
| 59 | +{ |
| 60 | + unsigned int tscale; |
| 61 | + long min_diff; |
| 62 | + |
| 63 | + *scale = 0; |
| 64 | + *step = 0; |
| 65 | + |
| 66 | + min_diff = baud; |
| 67 | + for (tscale = 0; tscale < AR933X_UART_MAX_SCALE; tscale++) { |
| 68 | + u64 tstep; |
| 69 | + int diff; |
| 70 | + |
| 71 | + tstep = baud * (tscale + 1); |
| 72 | + tstep *= (2 << 16); |
| 73 | + do_div(tstep, clk); |
| 74 | + |
| 75 | + if (tstep > AR933X_UART_MAX_STEP) |
| 76 | + break; |
| 77 | + |
| 78 | + diff = abs(ar933x_uart_get_baud(clk, tscale, tstep) - baud); |
| 79 | + if (diff < min_diff) { |
| 80 | + min_diff = diff; |
| 81 | + *scale = tscale; |
| 82 | + *step = tstep; |
| 83 | + } |
| 84 | + } |
| 85 | +} |
| 86 | + |
| 87 | static void ar933x_uart_set_termios(struct uart_port *port, |
| 88 | struct ktermios *new, |
| 89 | struct ktermios *old) |
| 90 | @@ -169,7 +230,7 @@ static void ar933x_uart_set_termios(stru |
| 91 | struct ar933x_uart_port *up = (struct ar933x_uart_port *) port; |
| 92 | unsigned int cs; |
| 93 | unsigned long flags; |
| 94 | - unsigned int baud, scale; |
| 95 | + unsigned int baud, scale, step; |
| 96 | |
| 97 | /* Only CS8 is supported */ |
| 98 | new->c_cflag &= ~CSIZE; |
| 99 | @@ -191,8 +252,8 @@ static void ar933x_uart_set_termios(stru |
| 100 | /* Mark/space parity is not supported */ |
| 101 | new->c_cflag &= ~CMSPAR; |
| 102 | |
| 103 | - baud = uart_get_baud_rate(port, new, old, 0, port->uartclk / 16); |
| 104 | - scale = (port->uartclk / (16 * baud)) - 1; |
| 105 | + baud = uart_get_baud_rate(port, new, old, up->min_baud, up->max_baud); |
| 106 | + ar933x_uart_get_scale_step(port->uartclk, baud, &scale, &step); |
| 107 | |
| 108 | /* |
| 109 | * Ok, we're now changing the port state. Do it with |
| 110 | @@ -200,6 +261,10 @@ static void ar933x_uart_set_termios(stru |
| 111 | */ |
| 112 | spin_lock_irqsave(&up->port.lock, flags); |
| 113 | |
| 114 | + /* disable the UART */ |
| 115 | + ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG, |
| 116 | + AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S); |
| 117 | + |
| 118 | /* Update the per-port timeout. */ |
| 119 | uart_update_timeout(port, new->c_cflag, baud); |
| 120 | |
| 121 | @@ -210,7 +275,7 @@ static void ar933x_uart_set_termios(stru |
| 122 | up->port.ignore_status_mask |= AR933X_DUMMY_STATUS_RD; |
| 123 | |
| 124 | ar933x_uart_write(up, AR933X_UART_CLOCK_REG, |
| 125 | - scale << AR933X_UART_CLOCK_SCALE_S | 8192); |
| 126 | + scale << AR933X_UART_CLOCK_SCALE_S | step); |
| 127 | |
| 128 | /* setup configuration register */ |
| 129 | ar933x_uart_rmw(up, AR933X_UART_CS_REG, AR933X_UART_CS_PARITY_M, cs); |
| 130 | @@ -219,6 +284,11 @@ static void ar933x_uart_set_termios(stru |
| 131 | ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, |
| 132 | AR933X_UART_CS_HOST_INT_EN); |
| 133 | |
| 134 | + /* reenable the UART */ |
| 135 | + ar933x_uart_rmw(up, AR933X_UART_CS_REG, |
| 136 | + AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S, |
| 137 | + AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S); |
| 138 | + |
| 139 | spin_unlock_irqrestore(&up->port.lock, flags); |
| 140 | |
| 141 | if (tty_termios_baud_rate(new)) |
| 142 | @@ -401,6 +471,8 @@ static void ar933x_uart_config_port(stru |
| 143 | static int ar933x_uart_verify_port(struct uart_port *port, |
| 144 | struct serial_struct *ser) |
| 145 | { |
| 146 | + struct ar933x_uart_port *up = (struct ar933x_uart_port *) port; |
| 147 | + |
| 148 | if (ser->type != PORT_UNKNOWN && |
| 149 | ser->type != PORT_AR933X) |
| 150 | return -EINVAL; |
| 151 | @@ -408,7 +480,8 @@ static int ar933x_uart_verify_port(struc |
| 152 | if (ser->irq < 0 || ser->irq >= NR_IRQS) |
| 153 | return -EINVAL; |
| 154 | |
| 155 | - if (ser->baud_base < 28800) |
| 156 | + if (ser->baud_base < up->min_baud || |
| 157 | + ser->baud_base > up->max_baud) |
| 158 | return -EINVAL; |
| 159 | |
| 160 | return 0; |
| 161 | @@ -561,6 +634,7 @@ static int __devinit ar933x_uart_probe(s |
| 162 | struct uart_port *port; |
| 163 | struct resource *mem_res; |
| 164 | struct resource *irq_res; |
| 165 | + unsigned int baud; |
| 166 | int id; |
| 167 | int ret; |
| 168 | |
| 169 | @@ -611,6 +685,12 @@ static int __devinit ar933x_uart_probe(s |
| 170 | port->fifosize = AR933X_UART_FIFO_SIZE; |
| 171 | port->ops = &ar933x_uart_ops; |
| 172 | |
| 173 | + baud = ar933x_uart_get_baud(port->uartclk, AR933X_UART_MAX_SCALE, 1); |
| 174 | + up->min_baud = max_t(unsigned int, baud, AR933X_UART_MIN_BAUD); |
| 175 | + |
| 176 | + baud = ar933x_uart_get_baud(port->uartclk, 0, AR933X_UART_MAX_STEP); |
| 177 | + up->max_baud = min_t(unsigned int, baud, AR933X_UART_MAX_BAUD); |
| 178 | + |
| 179 | ar933x_uart_add_console_port(up); |
| 180 | |
| 181 | ret = uart_add_one_port(&ar933x_uart_driver, &up->port); |
| 182 | |
