[PATCH/RFC] Add support for freescale watchdog to CPM serial driver.

[PATCH/RFC] Add support for freescale watchdog to CPM serial driver.

[Jochen Friedrich]

If a freescale watchdog device node is present, reset the watchdog
while waiting for serial input.

Signed-off-by: Jochen Friedrich <jochen@scram.de>
---
 arch/powerpc/boot/cpm-serial.c |   33 ++++++++++++++++++++++++++++++++-
 1 files changed, 32 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/boot/cpm-serial.c b/arch/powerpc/boot/cpm-serial.c
index 28296fa..d85f038 100644
--- a/arch/powerpc/boot/cpm-serial.c
+++ b/arch/powerpc/boot/cpm-serial.c
@@ -6,6 +6,9 @@
  *
  * It is assumed that the firmware (or the platform file) has already set
  * up the port.
+ *
+ * If a watchdog node exists, periodically reset the watchdog while waiting
+ * for console input.
  */
 
 #include "types.h"
@@ -50,7 +53,16 @@ struct cpm_bd {
 	u8 *addr; /* Buffer address in host memory */
 };
 
+struct pq_wdt {
+	u32 res0;
+	u32 swcrr; /* System watchdog control register */
+	u32 swcnr; /* System watchdog count register */
+	u8  res1[2];
+	u16 swsrr; /* System watchdog service register */
+};
+
 static void *cpcr;
+static struct pq_wdt *wdt;
 static struct cpm_param *param;
 static struct cpm_smc *smc;
 static struct cpm_scc *scc;
@@ -154,6 +166,11 @@ static void cpm_serial_putc(unsigned char c)
 
 static unsigned char cpm_serial_tstc(void)
 {
+	if (wdt) {
+		out_be16(&wdt->swsrr, 0x556c);
+		out_be16(&wdt->swsrr, 0xaa39);
+	}
+
 	barrier();
 	return !(rbdf->sc & 0x8000);
 }
@@ -178,7 +195,7 @@ int cpm_console_init(void *devp, struct serial_console_data *scdp)
 	void *reg_virt[2];
 	int is_smc = 0, is_cpm2 = 0, n;
 	unsigned long reg_phys;
-	void *parent, *muram;
+	void *parent, *muram, *watchdog;
 
 	if (dt_is_compatible(devp, "fsl,cpm1-smc-uart")) {
 		is_smc = 1;
@@ -260,6 +277,20 @@ int cpm_console_init(void *devp, struct serial_console_data *scdp)
 	if (n < 4)
 		return -1;
 
+	watchdog = finddevice("/soc/wdt");
+	if (watchdog && (dt_is_compatible(watchdog, "fsl,pq1-wdt") ||
+			 dt_is_compatible(watchdog, "fsl,pq2-wdt") ||
+			 dt_is_compatible(watchdog, "fsl,pq2pro-wdt"))) {
+		n = getprop(watchdog, "virtual-reg", reg_virt,
+			 sizeof(reg_virt));
+		if (n < (int)sizeof(reg_virt)) {
+			if (!dt_xlate_reg(watchdog, 0, &reg_phys, NULL))
+				return -1;
+			reg_virt[0] = (void *)reg_phys;
+		}
+		wdt = reg_virt[0];
+	}
+
 	scdp->open = cpm_serial_open;
 	scdp->putc = cpm_serial_putc;
 	scdp->getc = cpm_serial_getc;
-- 
1.5.3.7

Re: [PATCH/RFC] Add support for freescale watchdog to CPM serial driver.

[Scott Wood]

On Fri, Dec 28, 2007 at 04:18:36PM +0100, Jochen Friedrich wrote:
> If a freescale watchdog device node is present, reset the watchdog
> while waiting for serial input.

Hmm...  I don't like combining the watchdog and serial code together.  What
if some other serial device is used with this watchdog?  The serial driver
should only have to call an externally provided poke_watchdog() function.

-Scott