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authorDavid Woodhouse <dwmw2@org.rmk.(none)>2005-05-21 15:52:23 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2005-05-21 15:52:23 +0100
commit857dde2e79082d2954ede7f10783addaae956777 (patch)
tree5a7ba015eb22985d69e03e315b249c4c89750ee2
parent9636273dae265b9354b861b373cd43cd76a6d0fe (diff)
When we detect that a 16550 was in fact part of a NatSemi SuperIO chip
with high-speed mode enabled, we switch it to high-speed mode so that baud_base becomes 921600. However, we also need to multiply the baud divisor by 8 at the same time, in case it's already in use as a console. Signed-off-by: David Woodhouse Acked-by: Tom Rini Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--drivers/serial/8250.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 3bbf0cc6e53f..30e8beb71430 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -682,8 +682,6 @@ static void autoconfig_16550a(struct uart_8250_port *up)
* from EXCR1. Switch back to bank 0, change it in MCR. Then
* switch back to bank 2, read it from EXCR1 again and check
* it's changed. If so, set baud_base in EXCR2 to 921600. -- dwmw2
- * On PowerPC we don't want to change baud_base, as we have
- * a number of different divisors. -- Tom Rini
*/
serial_outp(up, UART_LCR, 0);
status1 = serial_in(up, UART_MCR);
@@ -699,16 +697,25 @@ static void autoconfig_16550a(struct uart_8250_port *up)
serial_outp(up, UART_MCR, status1);
if ((status2 ^ status1) & UART_MCR_LOOP) {
-#ifndef CONFIG_PPC
+ unsigned short quot;
+
serial_outp(up, UART_LCR, 0xE0);
+
+ quot = serial_inp(up, UART_DLM) << 8;
+ quot += serial_inp(up, UART_DLL);
+ quot <<= 3;
+
status1 = serial_in(up, 0x04); /* EXCR1 */
status1 &= ~0xB0; /* Disable LOCK, mask out PRESL[01] */
status1 |= 0x10; /* 1.625 divisor for baud_base --> 921600 */
serial_outp(up, 0x04, status1);
+
+ serial_outp(up, UART_DLL, quot & 0xff);
+ serial_outp(up, UART_DLM, quot >> 8);
+
serial_outp(up, UART_LCR, 0);
- up->port.uartclk = 921600*16;
-#endif
+ up->port.uartclk = 921600*16;
up->port.type = PORT_NS16550A;
up->capabilities |= UART_NATSEMI;
return;