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

[Jochen Friedrich <jochen@scram.de>]

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

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