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kernel: backport mtk_ppe busy-wait loop fix

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Fixes logic that leads to this error when booting mt7621 and other
devices that use the mediatek ethernet driver:
  [   23.144378] mtk_soc_eth 1e100000.ethernet: PPE table busy

Link: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=c5d66587b8900201e1530b7c18d41e87bd5812f4
Fixes: f07fe36f22 ("kernel: update flow offload patches to upstream version")
Cc: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
This commit is contained in:
Ilya Lipnitskiy 2021-04-17 15:33:39 -07:00 committed by Felix Fietkau
parent d1f1e5269e
commit 0e3c31c14c
1 changed files with 72 additions and 0 deletions
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72
target/linux/generic/backport-5.10/610-v5.13-35-net-ethernet-mediatek-ppe-fix-busy-wait-loop.patch Normal file
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@ -0,0 +1,72 @@
From c5d66587b8900201e1530b7c18d41e87bd5812f4 Mon Sep 17 00:00:00 2001
From: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Date: Thu, 15 Apr 2021 17:37:48 -0700
Subject: [PATCH] net: ethernet: mediatek: ppe: fix busy wait loop
The intention is for the loop to timeout if the body does not succeed.
The current logic calls time_is_before_jiffies(timeout) which is false
until after the timeout, so the loop body never executes.
Fix by using readl_poll_timeout as a more standard and less error-prone
solution.
Fixes: ba37b7caf1ed ("net: ethernet: mtk_eth_soc: add support for initializing the PPE")
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Cc: Felix Fietkau <nbd@nbd.name>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/ethernet/mediatek/mtk_ppe.c | 20 +++++++++-----------
drivers/net/ethernet/mediatek/mtk_ppe.h | 1 +
2 files changed, 10 insertions(+), 11 deletions(-)
--- a/drivers/net/ethernet/mediatek/mtk_ppe.c
+++ b/drivers/net/ethernet/mediatek/mtk_ppe.c
@@ -2,9 +2,8 @@
/* Copyright (C) 2020 Felix Fietkau <nbd@nbd.name> */
#include <linux/kernel.h>
-#include <linux/jiffies.h>
-#include <linux/delay.h>
#include <linux/io.h>
+#include <linux/iopoll.h>
#include <linux/etherdevice.h>
#include <linux/platform_device.h>
#include "mtk_ppe.h"
@@ -44,18 +43,17 @@ static u32 ppe_clear(struct mtk_ppe *ppe
static int mtk_ppe_wait_busy(struct mtk_ppe *ppe)
{
- unsigned long timeout = jiffies + HZ;
-
- while (time_is_before_jiffies(timeout)) {
- if (!(ppe_r32(ppe, MTK_PPE_GLO_CFG) & MTK_PPE_GLO_CFG_BUSY))
- return 0;
+ int ret;
+ u32 val;
- usleep_range(10, 20);
- }
+ ret = readl_poll_timeout(ppe->base + MTK_PPE_GLO_CFG, val,
+ !(val & MTK_PPE_GLO_CFG_BUSY),
+ 20, MTK_PPE_WAIT_TIMEOUT_US);
- dev_err(ppe->dev, "PPE table busy");
+ if (ret)
+ dev_err(ppe->dev, "PPE table busy");
- return -ETIMEDOUT;
+ return ret;
}
static void mtk_ppe_cache_clear(struct mtk_ppe *ppe)
--- a/drivers/net/ethernet/mediatek/mtk_ppe.h
+++ b/drivers/net/ethernet/mediatek/mtk_ppe.h
@@ -12,6 +12,7 @@
#define MTK_PPE_ENTRIES_SHIFT 3
#define MTK_PPE_ENTRIES (1024 << MTK_PPE_ENTRIES_SHIFT)
#define MTK_PPE_HASH_MASK (MTK_PPE_ENTRIES - 1)
+#define MTK_PPE_WAIT_TIMEOUT_US 1000000
#define MTK_FOE_IB1_UNBIND_TIMESTAMP GENMASK(7, 0)
#define MTK_FOE_IB1_UNBIND_PACKETS GENMASK(23, 8)