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path: root/drivers/tty/serial/8250/8250_dw.c
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Diffstat (limited to 'drivers/tty/serial/8250/8250_dw.c')
-rw-r--r--drivers/tty/serial/8250/8250_dw.c81
1 files changed, 77 insertions, 4 deletions
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index ed3113576740..51b307aab75e 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -62,6 +62,70 @@ struct dw8250_data {
struct uart_8250_dma dma;
};
+struct dw8250_acpi_desc {
+ void (*set_termios)(struct uart_port *p, struct ktermios *termios,
+ struct ktermios *old);
+};
+
+#define BYT_PRV_CLK 0x800
+#define BYT_PRV_CLK_EN (1 << 0)
+#define BYT_PRV_CLK_M_VAL_SHIFT 1
+#define BYT_PRV_CLK_N_VAL_SHIFT 16
+#define BYT_PRV_CLK_UPDATE (1 << 31)
+
+static void byt_set_termios(struct uart_port *p, struct ktermios *termios,
+ struct ktermios *old)
+{
+ unsigned int baud = tty_termios_baud_rate(termios);
+ unsigned int m, n;
+ u32 reg;
+
+ /*
+ * For baud rates 0.5M, 1M, 1.5M, 2M, 2.5M, 3M, 3.5M and 4M the
+ * dividers must be adjusted.
+ *
+ * uartclk = (m / n) * 100 MHz, where m <= n
+ */
+ switch (baud) {
+ case 500000:
+ case 1000000:
+ case 2000000:
+ case 4000000:
+ m = 64;
+ n = 100;
+ p->uartclk = 64000000;
+ break;
+ case 3500000:
+ m = 56;
+ n = 100;
+ p->uartclk = 56000000;
+ break;
+ case 1500000:
+ case 3000000:
+ m = 48;
+ n = 100;
+ p->uartclk = 48000000;
+ break;
+ case 2500000:
+ m = 40;
+ n = 100;
+ p->uartclk = 40000000;
+ break;
+ default:
+ m = 2304;
+ n = 3125;
+ p->uartclk = 73728000;
+ }
+
+ /* Reset the clock */
+ reg = (m << BYT_PRV_CLK_M_VAL_SHIFT) | (n << BYT_PRV_CLK_N_VAL_SHIFT);
+ writel(reg, p->membase + BYT_PRV_CLK);
+ reg |= BYT_PRV_CLK_EN | BYT_PRV_CLK_UPDATE;
+ writel(reg, p->membase + BYT_PRV_CLK);
+
+ serial8250_do_set_termios(p, termios, old);
+}
+
static inline int dw8250_modify_msr(struct uart_port *p, int offset, int value)
{
struct dw8250_data *d = p->private_data;
@@ -278,6 +342,7 @@ static int dw8250_probe_acpi(struct uart_8250_port *up,
{
const struct acpi_device_id *id;
struct uart_port *p = &up->port;
+ struct dw8250_acpi_desc *acpi_desc;
dw8250_setup_port(up);
@@ -290,14 +355,18 @@ static int dw8250_probe_acpi(struct uart_8250_port *up,
p->serial_out = dw8250_serial_out32;
p->regshift = 2;
- if (!p->uartclk)
- p->uartclk = (unsigned int)id->driver_data;
-
up->dma = &data->dma;
up->dma->rxconf.src_maxburst = p->fifosize / 4;
up->dma->txconf.dst_maxburst = p->fifosize / 4;
+ acpi_desc = (struct dw8250_acpi_desc *)id->driver_data;
+ if (!acpi_desc)
+ return 0;
+
+ if (acpi_desc->set_termios)
+ p->set_termios = acpi_desc->set_termios;
+
return 0;
}
@@ -445,12 +514,16 @@ static const struct of_device_id dw8250_of_match[] = {
};
MODULE_DEVICE_TABLE(of, dw8250_of_match);
+static struct dw8250_acpi_desc byt_8250_desc = {
+ .set_termios = byt_set_termios,
+};
+
static const struct acpi_device_id dw8250_acpi_match[] = {
{ "INT33C4", 0 },
{ "INT33C5", 0 },
{ "INT3434", 0 },
{ "INT3435", 0 },
- { "80860F0A", 0 },
+ { "80860F0A", (kernel_ulong_t)&byt_8250_desc},
{ },
};
MODULE_DEVICE_TABLE(acpi, dw8250_acpi_match);