Am 2022-12-02 19:23, schrieb Andrew Lunn:
On Fri, Dec 02, 2022 at 04:12:01PM +0100, Michael Walle wrote:
At least the GPY215B and GPY215C has a bug where it is still driving
the
interrupt line (MDINT) even after the interrupt status register is
read
and its bits are cleared. This will cause an interrupt storm.
Although the MDINT is multiplexed with a GPIO pin and theoretically we
could switch the pinmux to GPIO input mode, this isn't possible
because
the access to this register will stall exactly as long as the
interrupt
line is asserted. We exploit this very fact and just read a random
internal register in our interrupt handler. This way, it will be
delayed
until the external interrupt line is released and an interrupt storm
is
avoided.
The internal register access via the mailbox was deduced by looking at
the downstream PHY API because the datasheet doesn't mention any of
this.
Signed-off-by: Michael Walle <michael@xxxxxxxx>
---
drivers/net/phy/mxl-gpy.c | 83
+++++++++++++++++++++++++++++++++++++++
1 file changed, 83 insertions(+)
diff --git a/drivers/net/phy/mxl-gpy.c b/drivers/net/phy/mxl-gpy.c
index 0ff7ef076072..20e610dda891 100644
--- a/drivers/net/phy/mxl-gpy.c
+++ b/drivers/net/phy/mxl-gpy.c
@@ -9,6 +9,7 @@
#include <linux/module.h>
#include <linux/bitfield.h>
#include <linux/hwmon.h>
+#include <linux/mutex.h>
#include <linux/phy.h>
#include <linux/polynomial.h>
#include <linux/netdevice.h>
@@ -81,6 +82,14 @@
#define VSPEC1_TEMP_STA 0x0E
#define VSPEC1_TEMP_STA_DATA GENMASK(9, 0)
+/* Mailbox */
+#define VSPEC1_MBOX_DATA 0x5
+#define VSPEC1_MBOX_ADDRLO 0x6
+#define VSPEC1_MBOX_CMD 0x7
+#define VSPEC1_MBOX_CMD_ADDRHI GENMASK(7, 0)
+#define VSPEC1_MBOX_CMD_RD (0 << 8)
+#define VSPEC1_MBOX_CMD_READY BIT(15)
+
/* WoL */
#define VPSPEC2_WOL_CTL 0x0E06
#define VPSPEC2_WOL_AD01 0x0E08
@@ -88,7 +97,15 @@
#define VPSPEC2_WOL_AD45 0x0E0A
#define WOL_EN BIT(0)
+/* Internal registers, access via mbox */
+#define REG_GPIO0_OUT 0xd3ce00
+
struct gpy_priv {
+ struct phy_device *phydev;
+
+ /* serialize mailbox acesses */
+ struct mutex mbox_lock;
+
static int gpy_probe(struct phy_device *phydev)
{
struct device *dev = &phydev->mdio.dev;
@@ -228,7 +286,9 @@ static int gpy_probe(struct phy_device *phydev)
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
+ priv->phydev = phydev;
I don't think you use this anywhere. Maybe in one of the following
patches?
Arg. Yes, it's an leftover from when I was using a workqueue to
reenable the interrupts again.
Any opinion whether this patch should be net or net-next?
-michael
