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authorJonas Gorski <jogo@openwrt.org>2015-06-17 09:55:13 +0000
committerJonas Gorski <jogo@openwrt.org>2015-06-17 09:55:13 +0000
commit01796e87b169ef53d51f88a32d2550c1f914808a (patch)
treeba820f79412251ab7d0c95976989cb4ec0ed1fa0 /target/linux
parent9a59b350b7587eae4bcf6091b4dc86a4ee92bcf6 (diff)
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ar71xx: rb493g: fix gpio-mdio accesses under load
It seems that there are maximum timings for mdio accesses that can be hit when the system is under load and the thread is scheduled during a read or write access. Since there is no way of knowing if this happens as there is not even a parity bit, try to work around it by disabling interrupts during any gpio-mdio accesses. Performance impact seems to be neglectable, as mdio accesses are not that often. Hopefully fixes #19500. Signed-off-by: Jonas Gorski <jogo@openwrt.org> SVN-Revision: 46012
Diffstat (limited to 'target/linux')
-rw-r--r--target/linux/ar71xx/patches-3.18/904-phy-mdio-bitbang-prevent-rescheduling-during-command.patch61
1 files changed, 61 insertions, 0 deletions
diff --git a/target/linux/ar71xx/patches-3.18/904-phy-mdio-bitbang-prevent-rescheduling-during-command.patch b/target/linux/ar71xx/patches-3.18/904-phy-mdio-bitbang-prevent-rescheduling-during-command.patch
new file mode 100644
index 0000000000..68f86e0e09
--- /dev/null
+++ b/target/linux/ar71xx/patches-3.18/904-phy-mdio-bitbang-prevent-rescheduling-during-command.patch
@@ -0,0 +1,61 @@
+From 66e584435ac0de6e0abeb6d7166fe4fe25d6bb73 Mon Sep 17 00:00:00 2001
+From: Jonas Gorski <jogo@openwrt.org>
+Date: Tue, 16 Jun 2015 13:15:08 +0200
+Subject: [PATCH] phy/mdio-bitbang: prevent rescheduling during command
+
+It seems some phys have some maximum timings for accessing the MDIO line,
+resulting in bit errors under cpu stress. Prevent this from happening by
+disabling interrupts when sending commands.
+
+Signed-off-by: Jonas Gorski <jogo@openwrt.org>
+---
+ drivers/net/phy/mdio-bitbang.c | 9 +++++++++
+ 1 file changed, 9 insertions(+)
+
+--- a/drivers/net/phy/mdio-bitbang.c
++++ b/drivers/net/phy/mdio-bitbang.c
+@@ -17,6 +17,7 @@
+ * kind, whether express or implied.
+ */
+
++#include <linux/irqflags.h>
+ #include <linux/module.h>
+ #include <linux/mdio-bitbang.h>
+ #include <linux/types.h>
+@@ -156,7 +157,9 @@ static int mdiobb_read(struct mii_bus *b
+ {
+ struct mdiobb_ctrl *ctrl = bus->priv;
+ int ret, i;
++ long flags;
+
++ local_irq_save(flags);
+ if (reg & MII_ADDR_C45) {
+ reg = mdiobb_cmd_addr(ctrl, phy, reg);
+ mdiobb_cmd(ctrl, MDIO_C45_READ, phy, reg);
+@@ -169,13 +172,17 @@ static int mdiobb_read(struct mii_bus *b
+
+ ret = mdiobb_get_num(ctrl, 16);
+ mdiobb_get_bit(ctrl);
++ local_irq_restore(flags);
++
+ return ret;
+ }
+
+ static int mdiobb_write(struct mii_bus *bus, int phy, int reg, u16 val)
+ {
+ struct mdiobb_ctrl *ctrl = bus->priv;
++ long flags;
+
++ local_irq_save(flags);
+ if (reg & MII_ADDR_C45) {
+ reg = mdiobb_cmd_addr(ctrl, phy, reg);
+ mdiobb_cmd(ctrl, MDIO_C45_WRITE, phy, reg);
+@@ -190,6 +197,8 @@ static int mdiobb_write(struct mii_bus *
+
+ ctrl->ops->set_mdio_dir(ctrl, 0);
+ mdiobb_get_bit(ctrl);
++ local_irq_restore(flags);
++
+ return 0;
+ }
+