On Sun, Jan 2, 2022 at 7:36 PM Markus Koch markus@notsyncing.net wrote:
NXP's mEMAC reference manual, Chapter 6.5.5 "MDIO Ethernet Management Interface usage", specifies to poll the BSY (0) bit in the CFG (we call it CTL) register to wait until a transaction has finished, not bit 31 in the data register.
In the Linux kernel, this has already been fixed in commit 26eee0210ad7 ("net/fsl: fix a bug in xgmac_mdio").
Signed-off-by: Markus Koch markus@notsyncing.net
I only stumbled over this section of code while looking at something else, but I'm surprised this even works the way it is now. Maybe it's luck.
Sadly I have not yet had the chance to test this change on actual hardware, and I'm not sure I will anytime soon, so I'm asking whether there's anyone who could compile and run my code to see whether MDIO transactions work as expected.
Thanks! Markus
drivers/net/fm/memac_phy.c | 2 +- include/fsl_memac.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/fm/memac_phy.c b/drivers/net/fm/memac_phy.c index 72b500a6d1..0af6e83a8f 100644 --- a/drivers/net/fm/memac_phy.c +++ b/drivers/net/fm/memac_phy.c @@ -64,7 +64,7 @@ static int memac_wait_until_done(struct memac_mdio_controller *regs) { unsigned int timeout = MAX_NUM_RETRIES;
while ((memac_in_32(®s->mdio_data) & MDIO_DATA_BSY) && timeout--)
while ((memac_in_32(®s->mdio_ctl) & MDIO_CTL_BSY) && timeout--) ; if (!timeout) {diff --git a/include/fsl_memac.h b/include/fsl_memac.h index d067f1511c..d973fc0a5e 100644 --- a/include/fsl_memac.h +++ b/include/fsl_memac.h @@ -246,6 +246,7 @@ struct memac_mdio_controller { #define MDIO_STAT_HOLD_15_CLK (7 << 2) #define MDIO_STAT_NEG (1 << 23)
+#define MDIO_CTL_BSY (1 << 0) #define MDIO_CTL_DEV_ADDR(x) (x & 0x1f) #define MDIO_CTL_PORT_ADDR(x) ((x & 0x1f) << 5) #define MDIO_CTL_PRE_DIS (1 << 10) @@ -254,7 +255,6 @@ struct memac_mdio_controller { #define MDIO_CTL_READ (1 << 15)
#define MDIO_DATA(x) (x & 0xffff) -#define MDIO_DATA_BSY (1 << 31)
struct fsl_enet_mac;
-- 2.34.1
Reviewed-by: Ramon Fried rfried.dev@gmail.com