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From 8018869c6c8590018c1cd272475eda0dbf72a7ec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
Date: Fri, 7 Oct 2016 16:50:59 +0200
Subject: [PATCH] watchdog: bcm2835: Support setting reboot partition
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
The Raspberry Pi firmware looks at the RSTS register to know which
partition to boot from. The reboot syscall command
LINUX_REBOOT_CMD_RESTART2 supports passing in a string argument.
Add support for passing in a partition number 0..63 to boot from.
Partition 63 is a special partiton indicating halt.
If the partition doesn't exist, the firmware falls back to partition 0.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
---
drivers/watchdog/bcm2835_wdt.c | 49 +++++++++++++++++++---------------
1 file changed, 27 insertions(+), 22 deletions(-)
--- a/drivers/watchdog/bcm2835_wdt.c
+++ b/drivers/watchdog/bcm2835_wdt.c
@@ -31,13 +31,7 @@
#define PM_RSTC_WRCFG_SET 0x00000030
#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
#define PM_RSTC_RESET 0x00000102
-
-/*
- * The Raspberry Pi firmware uses the RSTS register to know which partition
- * to boot from. The partition value is spread into bits 0, 2, 4, 6, 8, 10.
- * Partition 63 is a special partition used by the firmware to indicate halt.
- */
-#define PM_RSTS_RASPBERRYPI_HALT 0x555
+#define PM_RSTS_PARTITION_CLR 0xfffffaaa
#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
@@ -94,9 +88,24 @@ static unsigned int bcm2835_wdt_get_time
return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
}
-static void __bcm2835_restart(struct bcm2835_wdt *wdt)
+/*
+ * The Raspberry Pi firmware uses the RSTS register to know which partiton
+ * to boot from. The partiton value is spread into bits 0, 2, 4, 6, 8, 10.
+ * Partiton 63 is a special partition used by the firmware to indicate halt.
+ */
+
+static void __bcm2835_restart(struct bcm2835_wdt *wdt, u8 partition)
{
- u32 val;
+ u32 val, rsts;
+
+ rsts = (partition & BIT(0)) | ((partition & BIT(1)) << 1) |
+ ((partition & BIT(2)) << 2) | ((partition & BIT(3)) << 3) |
+ ((partition & BIT(4)) << 4) | ((partition & BIT(5)) << 5);
+
+ val = readl_relaxed(wdt->base + PM_RSTS);
+ val &= PM_RSTS_PARTITION_CLR;
+ val |= PM_PASSWORD | rsts;
+ writel_relaxed(val, wdt->base + PM_RSTS);
/* use a timeout of 10 ticks (~150us) */
writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG);
@@ -114,7 +123,13 @@ static int bcm2835_restart(struct watchd
{
struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
- __bcm2835_restart(wdt);
+ unsigned long long val;
+ u8 partition = 0;
+
+ if (data && !kstrtoull(data, 0, &val) && val <= 63)
+ partition = val;
+
+ __bcm2835_restart(wdt, partition);
return 0;
}
@@ -152,19 +167,9 @@ static void bcm2835_power_off(void)
of_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm-wdt");
struct platform_device *pdev = of_find_device_by_node(np);
struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
- u32 val;
-
- /*
- * We set the watchdog hard reset bit here to distinguish this reset
- * from the normal (full) reset. bootcode.bin will not reboot after a
- * hard reset.
- */
- val = readl_relaxed(wdt->base + PM_RSTS);
- val |= PM_PASSWORD | PM_RSTS_RASPBERRYPI_HALT;
- writel_relaxed(val, wdt->base + PM_RSTS);
- /* Continue with normal reset mechanism */
- __bcm2835_restart(wdt);
+ /* Partition 63 tells the firmware that this is a halt */
+ __bcm2835_restart(wdt, 63);
}
static int bcm2835_wdt_probe(struct platform_device *pdev)
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