From 3fc55dbf79f2223eb436918c804944a737c97a10 Mon Sep 17 00:00:00 2001 From: David Bauer Date: Tue, 9 Jan 2024 20:52:56 +0100 Subject: [PATCH] ath79: read back reset register Read back the reset register in order to flush the cache. This fixes spurious reboot hangs on TP-Link TL-WDR3600 and TL-WDR4300 with Zentel DRAM chips. This issue was fixed in the past, but switching to the reset-driver specific implementation removed the cache barrier which was previously implicitly added by reading back the register in question. Link: https://github.com/freifunk-gluon/gluon/issues/2904 Link: https://github.com/openwrt/openwrt/issues/13043 Link: https://dev.archive.openwrt.org/ticket/17839 Link: f8a7bfe1cb2c ("MIPS: ath79: fix system restart") Signed-off-by: David Bauer (cherry picked from commit 2fe8ecd880396b5ae25fe9583aaa1d71be0b8468) --- ...reset-ath79-read-back-reset-register.patch | 33 +++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 target/linux/ath79/patches-5.15/100-reset-ath79-read-back-reset-register.patch diff --git a/target/linux/ath79/patches-5.15/100-reset-ath79-read-back-reset-register.patch b/target/linux/ath79/patches-5.15/100-reset-ath79-read-back-reset-register.patch new file mode 100644 index 0000000000..7aa501514d --- /dev/null +++ b/target/linux/ath79/patches-5.15/100-reset-ath79-read-back-reset-register.patch @@ -0,0 +1,33 @@ +From 661edfc3dab943a67c8821353b63cc23057f7ce9 Mon Sep 17 00:00:00 2001 +From: David Bauer +Date: Tue, 9 Jan 2024 20:48:46 +0100 +Subject: [PATCH] reset: ath79: read back reset register + +Read back the reset register in order to flush the cache. This fixes +spurious reboot hangs on TP-Link TL-WDR3600 and TL-WDR4300 with Zentel +DRAM chips. + +This issue was fixed in the past, but switching to the reset-driver +specific implementation removed the old fix. + +Link: https://github.com/freifunk-gluon/gluon/issues/2904 +Link: https://github.com/openwrt/openwrt/issues/13043 +Link: https://dev.archive.openwrt.org/ticket/17839 +Link: f8a7bfe1cb2c ("MIPS: ath79: fix system restart") + +Signed-off-by: David Bauer +--- + drivers/reset/reset-ath79.c | 2 ++ + 1 file changed, 2 insertions(+) + +--- a/drivers/reset/reset-ath79.c ++++ b/drivers/reset/reset-ath79.c +@@ -37,6 +37,8 @@ static int ath79_reset_update(struct res + else + val &= ~BIT(id); + writel(val, ath79_reset->base); ++ /* Flush cache */ ++ readl(ath79_reset->base); + spin_unlock_irqrestore(&ath79_reset->lock, flags); + + return 0; -- 2.25.1