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serial: fix DLL writes 

Commit 0147883450 tries to handle
word-sized writes to DLL/DLH, but due to a typo,
this patch is causing tracebacks in all Linux kernels running the PXA
serial driver, due to an unexpected DLL register value. Here is the
surrounding code from drivers/tty/serial/pxa.c:

	serial_out(up, UART_DLL, quot & 0xff);		/* LS of divisor */

	/*
	 * work around Errata #75 according to Intel(R) PXA27x
	 * Processor Family Specification Update (Nov 2005)
	 */
	dll = serial_in(up, UART_DLL);
	WARN_ON(dll != (quot & 0xff));	// <-- warning

Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Fixes: 0147883450
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2018-09-11 15:16:58 +02:00
parent 35f7f3fb5c
commit 61a9346f60
1 changed files with 2 additions and 2 deletions
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4
hw/char/serial.c
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@ -345,9 +345,9 @@ static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val,
default:
case 0:
if (s->lcr & UART_LCR_DLAB) {
if (size == 2) {
if (size == 1) {
s->divider = (s->divider & 0xff00) | val;
} else if (size == 4) {
} else {
s->divider = val;
}
serial_update_parameters(s);