If hardware is not initialised by bootloader after a hard reset
the MR1,MR2 registers may be 0xFF.
This causes the transmitter to never initialise and an infinite
loop to occur later.
Acked-By: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Signed-off-by: Martin Fuzzey <mfuzzey@xxxxxxxxx>
---
drivers/serial/sc26xx.c | 23 +++++++++++++++++++++++
1 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/drivers/serial/sc26xx.c b/drivers/serial/sc26xx.c
index 09e73a3..2e17bbc 100644
--- a/drivers/serial/sc26xx.c
+++ b/drivers/serial/sc26xx.c
@@ -832,6 +832,27 @@ static const struct chip_def * __devinit detect_chip_type(
return chip;
}
+static void __devinit hw_init(struct uart_port *port)
+{
+ u8 mr;
+
+ /* Sometimes on cold boot MR1,MR2 are 0xFF (reset problem?)
+ * Initialise if channel mode in MR2 is not normal otherwise
+ * assume bootloader has done the init.
+ */
+ write_cmd_port(port, CR_RES_MR); /* MR1 */
+ READ_SC_PORT(port, MRx); /* skip MR1 */
+ mr = READ_SC_PORT(port, MRx);
+ if (mr & 0xC0) {
+ write_cmd_port(port, CR_RES_MR);
+
+ /* Values below are arbitary (will be changed by set_termios)
+ * but must be different so that chip detection works */
+ WRITE_SC_PORT(port, MRx, 0x10);
+ WRITE_SC_PORT(port, MRx, 0x00);
+ }
+}
+
static int __devinit sc26xx_probe(struct platform_device *dev)
{
struct resource *res, *irq_res;
@@ -869,6 +890,7 @@ static int __devinit sc26xx_probe(struct platform_device *dev)
up->port[0].dev = &dev->dev;
sc26xx_init_masks(up, 0, pdata->signal_map[0]);
+ hw_init(&up->port[0]);
sc26xx_port = &up->port[0];
@@ -876,6 +898,7 @@ static int __devinit sc26xx_probe(struct platform_device *dev)
up->port[1].line = 1;
sc26xx_init_masks(up, 1, pdata->signal_map[1]);
+ hw_init(&up->port[1]);
if (pdata->chip_name)
up->chip = chip_by_name(pdata->chip_name);
--
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