This is a note to let you know that I've just added the patch titled
net/fsl: xgmac_mdio: Add workaround for erratum A-009885
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-fsl-xgmac_mdio-add-workaround-for-erratum-a-009885.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6198c722019774d38018457a8bfb9ba3ed8c931e Mon Sep 17 00:00:00 2001
From: Tobias Waldekranz <tobias@xxxxxxxxxxxxxx>
Date: Tue, 18 Jan 2022 22:50:50 +0100
Subject: net/fsl: xgmac_mdio: Add workaround for erratum A-009885
From: Tobias Waldekranz <tobias@xxxxxxxxxxxxxx>
commit 6198c722019774d38018457a8bfb9ba3ed8c931e upstream.
Once an MDIO read transaction is initiated, we must read back the data
register within 16 MDC cycles after the transaction completes. Outside
of this window, reads may return corrupt data.
Therefore, disable local interrupts in the critical section, to
maximize the probability that we can satisfy this requirement.
Fixes: d55ad2967d89 ("powerpc/mpc85xx: Create dts components for the FSL QorIQ DPAA FMan")
Signed-off-by: Tobias Waldekranz <tobias@xxxxxxxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/freescale/xgmac_mdio.c | 25 +++++++++++++++++++------
1 file changed, 19 insertions(+), 6 deletions(-)
--- a/drivers/net/ethernet/freescale/xgmac_mdio.c
+++ b/drivers/net/ethernet/freescale/xgmac_mdio.c
@@ -49,6 +49,7 @@ struct tgec_mdio_controller {
struct mdio_fsl_priv {
struct tgec_mdio_controller __iomem *mdio_base;
bool is_little_endian;
+ bool has_a009885;
bool has_a011043;
};
@@ -184,10 +185,10 @@ static int xgmac_mdio_read(struct mii_bu
{
struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
+ unsigned long flags;
uint16_t dev_addr;
uint32_t mdio_stat;
uint32_t mdio_ctl;
- uint16_t value;
int ret;
bool endian = priv->is_little_endian;
@@ -219,12 +220,18 @@ static int xgmac_mdio_read(struct mii_bu
return ret;
}
+ if (priv->has_a009885)
+ /* Once the operation completes, i.e. MDIO_STAT_BSY clears, we
+ * must read back the data register within 16 MDC cycles.
+ */
+ local_irq_save(flags);
+
/* Initiate the read */
xgmac_write32(mdio_ctl | MDIO_CTL_READ, ®s->mdio_ctl, endian);
ret = xgmac_wait_until_done(&bus->dev, regs, endian);
if (ret)
- return ret;
+ goto irq_restore;
/* Return all Fs if nothing was there */
if ((xgmac_read32(®s->mdio_stat, endian) & MDIO_STAT_RD_ER) &&
@@ -232,13 +239,17 @@ static int xgmac_mdio_read(struct mii_bu
dev_dbg(&bus->dev,
"Error while reading PHY%d reg at %d.%hhu\n",
phy_id, dev_addr, regnum);
- return 0xffff;
+ ret = 0xffff;
+ } else {
+ ret = xgmac_read32(®s->mdio_data, endian) & 0xffff;
+ dev_dbg(&bus->dev, "read %04x\n", ret);
}
- value = xgmac_read32(®s->mdio_data, endian) & 0xffff;
- dev_dbg(&bus->dev, "read %04x\n", value);
+irq_restore:
+ if (priv->has_a009885)
+ local_irq_restore(flags);
- return value;
+ return ret;
}
static int xgmac_mdio_probe(struct platform_device *pdev)
@@ -282,6 +293,8 @@ static int xgmac_mdio_probe(struct platf
priv->is_little_endian = device_property_read_bool(&pdev->dev,
"little-endian");
+ priv->has_a009885 = device_property_read_bool(&pdev->dev,
+ "fsl,erratum-a009885");
priv->has_a011043 = device_property_read_bool(&pdev->dev,
"fsl,erratum-a011043");
Patches currently in stable-queue which might be from tobias@xxxxxxxxxxxxxx are
queue-5.10/powerpc-fsl-dts-enable-wa-for-erratum-a-009885-on-fman3l-mdio-buses.patch
queue-5.10/net-fsl-xgmac_mdio-fix-incorrect-iounmap-when-removing-module.patch
queue-5.10/net-fsl-xgmac_mdio-add-workaround-for-erratum-a-009885.patch
