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Subject[PATCH net-next,v2] net: ethernet: mediatek: ppe: fix busy wait loop
Date
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>
---
drivers/net/ethernet/mediatek/mtk_ppe.c | 18 +++++++++---------
drivers/net/ethernet/mediatek/mtk_ppe.h | 1 +
2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_ppe.c b/drivers/net/ethernet/mediatek/mtk_ppe.c
index 71e1ccea6e72..f4b3fc0eeb50 100644
--- a/drivers/net/ethernet/mediatek/mtk_ppe.c
+++ b/drivers/net/ethernet/mediatek/mtk_ppe.c
@@ -5,6 +5,7 @@
#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 +45,17 @@ static u32 ppe_clear(struct mtk_ppe *ppe, u32 reg, u32 val)

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)
diff --git a/drivers/net/ethernet/mediatek/mtk_ppe.h b/drivers/net/ethernet/mediatek/mtk_ppe.h
index 51bd5e75bbbd..242fb8f2ae65 100644
--- 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)
--
2.31.1
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