[PATCH] Serial: Convert 8250 revision-based bug fixes to bug bitmask
For some 8250 port types, we used to check the type of the port, and
then determine whether the chip revision means the device is buggy.
Instead, introduce a bit array, and set the appropriate bit(s) when
we discover a buggy device.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 30e8beb..27cc288 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -132,9 +132,9 @@
struct uart_port port;
struct timer_list timer; /* "no irq" timer */
struct list_head list; /* ports on this IRQ */
- unsigned int capabilities; /* port capabilities */
+ unsigned short capabilities; /* port capabilities */
+ unsigned short bugs; /* port bugs */
unsigned int tx_loadsz; /* transmit fifo load size */
- unsigned short rev;
unsigned char acr;
unsigned char ier;
unsigned char lcr;
@@ -560,7 +560,14 @@
if (id1 == 0x16 && id2 == 0xC9 &&
(id3 == 0x50 || id3 == 0x52 || id3 == 0x54)) {
up->port.type = PORT_16C950;
- up->rev = rev | (id3 << 8);
+
+ /*
+ * Enable work around for the Oxford Semiconductor 952 rev B
+ * chip which causes it to seriously miscalculate baud rates
+ * when DLL is 0.
+ */
+ if (id3 == 0x52 && rev == 0x01)
+ up->bugs |= UART_BUG_QUOT;
return;
}
@@ -577,8 +584,6 @@
id2 = id1 >> 8;
if (id2 == 0x10 || id2 == 0x12 || id2 == 0x14) {
- if (id2 == 0x10)
- up->rev = id1 & 255;
up->port.type = PORT_16850;
return;
}
@@ -809,6 +814,7 @@
// save_flags(flags); cli();
up->capabilities = 0;
+ up->bugs = 0;
if (!(up->port.flags & UPF_BUGGY_UART)) {
/*
@@ -1677,12 +1683,9 @@
quot = serial8250_get_divisor(port, baud);
/*
- * Work around a bug in the Oxford Semiconductor 952 rev B
- * chip which causes it to seriously miscalculate baud rates
- * when DLL is 0.
+ * Oxford Semi 952 rev B workaround
*/
- if ((quot & 0xff) == 0 && up->port.type == PORT_16C950 &&
- up->rev == 0x5201)
+ if (up->bugs & UART_BUG_QUOT && (quot & 0xff) == 0)
quot ++;
if (up->capabilities & UART_CAP_FIFO && up->port.fifosize > 1) {