[RFC PATCH net-next v3 04/20] net: dsa: qca8k: handle qca8k_set_page errors

Ansuel Smith
2021-05-04T22:29:47Z

With a remote possibility, the set_page function can fail. Since this is
a critical part of the write/read qca8k regs, propagate the error and
terminate any read/write operation.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
---
drivers/net/dsa/qca8k.c | 29 +++++++++++++++++++++++------
1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index cdaf9f85a2cb..411b42d38819 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -127,16 +127,20 @@ qca8k_mii_write32(struct mii_bus *bus, int phy_id, u32 regnum, u32 val)
"failed to write qca8k 32bit register\n");
}

-static void
+static int
qca8k_set_page(struct mii_bus *bus, u16 page)
{
if (page == qca8k_current_page)
- return;
+ return 0;

- if (bus->write(bus, 0x18, 0, page) < 0)
+ if (bus->write(bus, 0x18, 0, page) < 0) {
dev_err_ratelimited(&bus->dev,
"failed to set qca8k page\n");
+ return -EBUSY;
+ }
+
qca8k_current_page = page;
+ return 0;
}

static u32
@@ -149,9 +153,13 @@ qca8k_read(struct qca8k_priv *priv, u32 reg)

mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED);

- qca8k_set_page(priv->bus, page);
+ val = qca8k_set_page(priv->bus, page);
+ if (val < 0)
+ goto exit;
+
val = qca8k_mii_read32(priv->bus, 0x10 | r2, r1);

+exit:
mutex_unlock(&priv->bus->mdio_lock);

return val;
@@ -161,14 +169,19 @@ static void
qca8k_write(struct qca8k_priv *priv, u32 reg, u32 val)
{
u16 r1, r2, page;
+ int ret;

qca8k_split_addr(reg, &r1, &r2, &page);

mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED);

- qca8k_set_page(priv->bus, page);
+ ret = qca8k_set_page(priv->bus, page);
+ if (ret < 0)
+ goto exit;
+
qca8k_mii_write32(priv->bus, 0x10 | r2, r1, val);

+exit:
mutex_unlock(&priv->bus->mdio_lock);
}

@@ -182,12 +195,16 @@ qca8k_rmw(struct qca8k_priv *priv, u32 reg, u32 mask, u32 val)

mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED);

- qca8k_set_page(priv->bus, page);
+ ret = qca8k_set_page(priv->bus, page);
+ if (ret < 0)
+ goto exit;
+
ret = qca8k_mii_read32(priv->bus, 0x10 | r2, r1);
ret &= ~mask;
ret |= val;
qca8k_mii_write32(priv->bus, 0x10 | r2, r1, ret);

+exit:
mutex_unlock(&priv->bus->mdio_lock);

return ret;
--
2.30.2