[PATCH v2] serial: 8250_dw: Improve unwritable LCR workaround
From: James Hogan <hidden>
Date: 2013-12-06 23:51:42
Also in:
linux-serial, lkml
On Friday 06 December 2013 23:29:02 James Hogan wrote:
quoted hunk ↗ jump to hunk
So it looks like the LCR does always change immediately for me in this case (obviously it hasn't hit the BUSY case), but not all the bits can be written. In particular bit 5 and bit 7 at the least. If I do this (sorry for whitespace munging):diff --git a/drivers/tty/serial/8250/8250_dw.cb/drivers/tty/serial/8250/8250_dw.c index 4658e3e..722d448 100644--- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c@@ -96,7 +96,7 @@ static void dw8250_serial_out(struct uart_port *p, intoffset, int value) if (offset == UART_LCR) { int tries = 1000; while (tries--) { - if (value == p->serial_in(p, UART_LCR)) + if (value & ~0xa0 == p->serial_in(p, UART_LCR) & ~0xa0) return; dw8250_force_idle(p); writeb(value, p->membase + (UART_LCR << p->regshift));@@ -132,7 +132,7 @@ static void dw8250_serial_out32(struct uart_port *p, intoffset, int value) if (offset == UART_LCR) { int tries = 1000; while (tries--) { - if (value == p->serial_in(p, UART_LCR)) + if (value & ~0xa0 == p->serial_in(p, UART_LCR) & ~0xa0)
My appologies, that should have had some more brackets (I should have retested after cleaning up my debugging). I.e. + if ((value & ~0xa0) == (p->serial_in(p, UART_LCR) & ~0xa0)) Cheers James -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 836 bytes Desc: This is a digitally signed message part. URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20131206/bac2c317/attachment.sig>