| Message ID | 20241119095141.1236414-1-jacky_chou@aspeedtech.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,v2] net: mdio: aspeed: Add dummy read for fire control | expand |
On Tue, Nov 19, 2024 at 05:51:41PM +0800, Jacky Chou wrote: > When the command bus is sometimes busy, it may cause the command is not > arrived to MDIO controller immediately. On software, the driver issues a > write command to the command bus does not wait for command complete and > it returned back to code immediately. But a read command will wait for > the data back, once a read command was back indicates the previous write > command had arrived to controller. > Add a dummy read to ensure triggering mdio controller before starting > polling the status of mdio controller to avoid polling unexpected timeout. Please have another attempt at writing the commit message. > Fixes: a9770eac511a ("net: mdio: Move MDIO drivers into a new subdirectory") > Signed-off-by: Jacky Chou <jacky_chou@aspeedtech.com> > --- > drivers/net/mdio/mdio-aspeed.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/net/mdio/mdio-aspeed.c b/drivers/net/mdio/mdio-aspeed.c > index c2170650415c..373902d33b96 100644 > --- a/drivers/net/mdio/mdio-aspeed.c > +++ b/drivers/net/mdio/mdio-aspeed.c > @@ -62,6 +62,8 @@ static int aspeed_mdio_op(struct mii_bus *bus, u8 st, u8 op, u8 phyad, u8 regad, > | FIELD_PREP(ASPEED_MDIO_DATA_MIIRDATA, data); > > iowrite32(ctrl, ctx->base + ASPEED_MDIO_CTRL); > + /* Add dummy read to ensure triggering mdio controller */ > + (void)ioread32(ctx->base + ASPEED_MDIO_CTRL); Maybe: /* Dummy read to flush previous write to controller */ Andrew --- pw-bot: cr
Hi Andrew Lunn, Thank you for your reply. > > When the command bus is sometimes busy, it may cause the command is > > not arrived to MDIO controller immediately. On software, the driver > > issues a write command to the command bus does not wait for command > > complete and it returned back to code immediately. But a read command > > will wait for the data back, once a read command was back indicates > > the previous write command had arrived to controller. > > Add a dummy read to ensure triggering mdio controller before starting > > polling the status of mdio controller to avoid polling unexpected timeout. > > Please have another attempt at writing the commit message. > > > Fixes: a9770eac511a ("net: mdio: Move MDIO drivers into a new > > subdirectory") > > Signed-off-by: Jacky Chou <jacky_chou@aspeedtech.com> > > --- > > drivers/net/mdio/mdio-aspeed.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/net/mdio/mdio-aspeed.c > > b/drivers/net/mdio/mdio-aspeed.c index c2170650415c..373902d33b96 > > 100644 > > --- a/drivers/net/mdio/mdio-aspeed.c > > +++ b/drivers/net/mdio/mdio-aspeed.c > > @@ -62,6 +62,8 @@ static int aspeed_mdio_op(struct mii_bus *bus, u8 st, > u8 op, u8 phyad, u8 regad, > > | FIELD_PREP(ASPEED_MDIO_DATA_MIIRDATA, data); > > > > iowrite32(ctrl, ctx->base + ASPEED_MDIO_CTRL); > > + /* Add dummy read to ensure triggering mdio controller */ > > + (void)ioread32(ctx->base + ASPEED_MDIO_CTRL); > > Maybe: /* Dummy read to flush previous write to controller */ Agree. I will change the title in next version. Thanks, Jacky
diff --git a/drivers/net/mdio/mdio-aspeed.c b/drivers/net/mdio/mdio-aspeed.c index c2170650415c..373902d33b96 100644 --- a/drivers/net/mdio/mdio-aspeed.c +++ b/drivers/net/mdio/mdio-aspeed.c @@ -62,6 +62,8 @@ static int aspeed_mdio_op(struct mii_bus *bus, u8 st, u8 op, u8 phyad, u8 regad, | FIELD_PREP(ASPEED_MDIO_DATA_MIIRDATA, data); iowrite32(ctrl, ctx->base + ASPEED_MDIO_CTRL); + /* Add dummy read to ensure triggering mdio controller */ + (void)ioread32(ctx->base + ASPEED_MDIO_CTRL); return readl_poll_timeout(ctx->base + ASPEED_MDIO_CTRL, ctrl, !(ctrl & ASPEED_MDIO_CTRL_FIRE),
When the command bus is sometimes busy, it may cause the command is not arrived to MDIO controller immediately. On software, the driver issues a write command to the command bus does not wait for command complete and it returned back to code immediately. But a read command will wait for the data back, once a read command was back indicates the previous write command had arrived to controller. Add a dummy read to ensure triggering mdio controller before starting polling the status of mdio controller to avoid polling unexpected timeout. Fixes: a9770eac511a ("net: mdio: Move MDIO drivers into a new subdirectory") Signed-off-by: Jacky Chou <jacky_chou@aspeedtech.com> --- drivers/net/mdio/mdio-aspeed.c | 2 ++ 1 file changed, 2 insertions(+)