[openwrt/openwrt] ramips: manage low reset lines

[LEDE Commits]

ynezz pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/69551a244292f5baf0aee205ec6b891a03f1ee15

commit 69551a244292f5baf0aee205ec6b891a03f1ee15
Author: Sander Vanheule <sander at svanheule.net>
AuthorDate: Thu Feb 4 15:49:14 2021 +0100

    ramips: manage low reset lines
    
    The bootloader of a number of recent TP-Link devices does not properly
    initialise the MT7621's internal switch when booting from flash. To
    enable the mt7530 driver to clear the reset on the switch, the ramips
    reset controller must be allowed to toggle these.
    
    Backport upstream commit 3f9ef7785a9c from mips-next to allow control of
    the "mcm" reset line.
    
    Signed-off-by: Sander Vanheule <sander at svanheule.net>
---
 .../0123-mips-ralink-manage-low-reset-lines.patch  | 47 ++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/target/linux/ramips/patches-5.4/0123-mips-ralink-manage-low-reset-lines.patch b/target/linux/ramips/patches-5.4/0123-mips-ralink-manage-low-reset-lines.patch
new file mode 100644
index 0000000000..e59044dd96
--- /dev/null
+++ b/target/linux/ramips/patches-5.4/0123-mips-ralink-manage-low-reset-lines.patch
@@ -0,0 +1,47 @@
+From 3f9ef7785a9cd69cb75f5e2ea4ca79a24752e496 Mon Sep 17 00:00:00 2001
+From: Sander Vanheule <sander at svanheule.net>
+Date: Wed, 3 Feb 2021 10:21:41 +0100
+Subject: MIPS: ralink: manage low reset lines
+
+Reset lines with indices smaller than 8 are currently considered invalid
+by the rt2880-reset reset controller.
+
+The MT7621 SoC uses a number of these low reset lines. The DTS defines
+reset lines "hsdma", "fe", and "mcm" with respective values 5, 6, and 2.
+As a result of the above restriction, these resets cannot be asserted or
+de-asserted by the reset controller. In cases where the bootloader does
+not de-assert these lines, this results in e.g. the MT7621's internal
+switch staying in reset.
+
+Change the reset controller to only ignore the system reset, so all
+reset lines with index greater than 0 are considered valid.
+
+Signed-off-by: Sander Vanheule <sander at svanheule.net>
+Acked-by: John Crispin <john at phrozen.org>
+Signed-off-by: Thomas Bogendoerfer <tsbogend at alpha.franken.de>
+---
+ arch/mips/ralink/reset.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/arch/mips/ralink/reset.c b/arch/mips/ralink/reset.c
+index 8126f12604071..274d33078c5eb 100644
+--- a/arch/mips/ralink/reset.c
++++ b/arch/mips/ralink/reset.c
+@@ -27,7 +27,7 @@ static int ralink_assert_device(struct reset_controller_dev *rcdev,
+ {
+ 	u32 val;
+ 
+-	if (id < 8)
++	if (id == 0)
+ 		return -1;
+ 
+ 	val = rt_sysc_r32(SYSC_REG_RESET_CTRL);
+@@ -42,7 +42,7 @@ static int ralink_deassert_device(struct reset_controller_dev *rcdev,
+ {
+ 	u32 val;
+ 
+-	if (id < 8)
++	if (id == 0)
+ 		return -1;
+ 
+ 	val = rt_sysc_r32(SYSC_REG_RESET_CTRL);