From: "Chew, Chiau Ee" <chiau.ee.c...@intel.com>
This will enable high speed baud rates namely 1M, 2M, 3M, and 4M
in Intel Baytrail Designware controller.
Signed-off-by: Chew, Chiau Ee <chiau.ee.c...@intel.com>
Signed-off-by: Maurice Petallo <mauricex.r.peta...@intel.com>
---
drivers/tty/serial/8250/8250_dw.c | 43 +++++++++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)
diff --git a/drivers/tty/serial/8250/8250_dw.c
b/drivers/tty/serial/8250/8250_dw.c
index 2731c08..8df7d99 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -124,6 +124,48 @@ static unsigned int dw8250_serial_in32(struct uart_port
*p, int offset)
return dw8250_modify_msr(p, offset, value);
}
+#define LPSS_PRV_CLK 0x800
+#define LPSS_PRV_CLK_EN (1 << 0)
+#define LPSS_PRV_CLK_M_VAL_SHIFT 1
+#define LPSS_PRV_CLK_N_VAL_SHIFT 16
+#define LPSS_PRV_CLK_UPDATE (1 << 31)
+
+static void
+dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
+ struct ktermios *old)
+{
+ unsigned int baud = tty_termios_baud_rate(termios);
+ unsigned int m = 6912;
+ unsigned int n = 15625;
+ u32 reg;
+
+ /*
+ * For baud rates 1000000, 2000000 and 4000000 the dividers must be
+ * adjusted.
+ */
+ if (baud == 1000000 || baud == 2000000 || baud == 4000000) {
+ m = 64;
+ n = 100;
+
+ p->uartclk = 64000000;
+ } else if (baud == 3000000) {
+ m = 48;
+ n = 100;
+
+ p->uartclk = 48000000;
+ } else {
+ p->uartclk = 44236800;
+ }
+
+ /* Reset the clock */
+ reg = (m << LPSS_PRV_CLK_M_VAL_SHIFT) | (n << LPSS_PRV_CLK_N_VAL_SHIFT);
+ writel(reg, p->membase + LPSS_PRV_CLK);
+ reg |= LPSS_PRV_CLK_EN | LPSS_PRV_CLK_UPDATE;
+ writel(reg, p->membase + LPSS_PRV_CLK);
+
+ serial8250_do_set_termios(p, termios, old);
+}
+
static int dw8250_handle_irq(struct uart_port *p)
{
struct dw8250_data *d = p->private_data;
@@ -265,6 +307,7 @@ static int dw8250_probe_acpi(struct uart_8250_port *up,
p->iotype = UPIO_MEM32;
p->serial_in = dw8250_serial_in32;
p->serial_out = dw8250_serial_out32;
+ p->set_termios = dw8250_set_termios;
p->regshift = 2;
if (!p->uartclk)
--
1.9.1
--
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