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Diffstat (limited to 'drivers/soc/bcm/brcmstb/pm/pm-arm.c')
-rw-r--r--drivers/soc/bcm/brcmstb/pm/pm-arm.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/drivers/soc/bcm/brcmstb/pm/pm-arm.c b/drivers/soc/bcm/brcmstb/pm/pm-arm.c
index 775da69b8efa..d681cd24c6e1 100644
--- a/drivers/soc/bcm/brcmstb/pm/pm-arm.c
+++ b/drivers/soc/bcm/brcmstb/pm/pm-arm.c
@@ -25,7 +25,6 @@
#include <linux/kernel.h>
#include <linux/memblock.h>
#include <linux/module.h>
-#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/panic_notifier.h>
@@ -664,7 +663,20 @@ static void __iomem *brcmstb_ioremap_match(const struct of_device_id *matches,
return of_io_request_and_map(dn, index, dn->full_name);
}
-
+/*
+ * The AON is a small domain in the SoC that can retain its state across
+ * various system wide sleep states and specific reset conditions; the
+ * AON DATA RAM is a small RAM of a few words (< 1KB) which can store
+ * persistent information across such events.
+ *
+ * The purpose of the below panic notifier is to help with notifying
+ * the bootloader that a panic occurred and so that it should try its
+ * best to preserve the DRAM contents holding that buffer for recovery
+ * by the kernel as opposed to wiping out DRAM clean again.
+ *
+ * Reference: comment from Florian Fainelli, at
+ * https://lore.kernel.org/lkml/781cafb0-8d06-8b56-907a-5175c2da196a@gmail.com
+ */
static int brcmstb_pm_panic_notify(struct notifier_block *nb,
unsigned long action, void *data)
{