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SubjectRe: [PATCH 1/2] drivers: net: mdio-sun4i: Speedup mdio read and write
Date
Dne torek, 06. september 2022 ob 09:56:15 CEST je qianfanguijin@163.com 
napisal(a):
> From: qianfan Zhao <qianfanguijin@163.com>
>
> msleep(1) on my board takes about 30ms, and it is too long to accept.
> Use read_poll_timeout to speedup.
>
> Signed-off-by: qianfan Zhao <qianfanguijin@163.com>
> ---
> drivers/net/mdio/mdio-sun4i.c | 29 ++++++++++++-----------------
> 1 file changed, 12 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/net/mdio/mdio-sun4i.c b/drivers/net/mdio/mdio-sun4i.c
> index f798de3276dc..168e2a375535 100644
> --- a/drivers/net/mdio/mdio-sun4i.c
> +++ b/drivers/net/mdio/mdio-sun4i.c
> @@ -26,8 +26,6 @@
> #define EMAC_MAC_MIND_REG (0x10)
> #define EMAC_MAC_SSRR_REG (0x14)
>
> -#define MDIO_TIMEOUT (msecs_to_jiffies(100))
> -
> struct sun4i_mdio_data {
> void __iomem *membase;
> struct regulator *regulator;
> @@ -36,8 +34,7 @@ struct sun4i_mdio_data {
> static int sun4i_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
> {
> struct sun4i_mdio_data *data = bus->priv;
> - unsigned long timeout_jiffies;
> - int value;
> + int ret, tmp, value;
>
> /* issue the phy address and reg */
> writel((mii_id << 8) | regnum, data->membase + EMAC_MAC_MADR_REG);
> @@ -45,12 +42,11 @@ static int sun4i_mdio_read(struct mii_bus *bus, int
> mii_id, int regnum) writel(0x1, data->membase + EMAC_MAC_MCMD_REG);
>
> /* Wait read complete */
> - timeout_jiffies = jiffies + MDIO_TIMEOUT;
> - while (readl(data->membase + EMAC_MAC_MIND_REG) & 0x1) {
> - if (time_is_before_jiffies(timeout_jiffies))
> - return -ETIMEDOUT;
> - msleep(1);
> - }
> + ret = read_poll_timeout(readl, tmp, (tmp & 1) == 0,
> + 20, 10000, false,
> + data->membase +
EMAC_MAC_MIND_REG);

You should use readl_poll_timeout() instead, as instructed by documentation.
Additionally, are you sure about both delay parameters? They are both much
smaller than in original code.

Same comments apply to patch 2.

Best regards,
Jernej

> + if (ret < 0)
> + return ret;
>
> /* push down the phy io line */
> writel(0x0, data->membase + EMAC_MAC_MCMD_REG);
> @@ -64,7 +60,7 @@ static int sun4i_mdio_write(struct mii_bus *bus, int
> mii_id, int regnum, u16 value)
> {
> struct sun4i_mdio_data *data = bus->priv;
> - unsigned long timeout_jiffies;
> + int ret, tmp;
>
> /* issue the phy address and reg */
> writel((mii_id << 8) | regnum, data->membase + EMAC_MAC_MADR_REG);
> @@ -72,12 +68,11 @@ static int sun4i_mdio_write(struct mii_bus *bus, int
> mii_id, int regnum, writel(0x1, data->membase + EMAC_MAC_MCMD_REG);
>
> /* Wait read complete */
> - timeout_jiffies = jiffies + MDIO_TIMEOUT;
> - while (readl(data->membase + EMAC_MAC_MIND_REG) & 0x1) {
> - if (time_is_before_jiffies(timeout_jiffies))
> - return -ETIMEDOUT;
> - msleep(1);
> - }
> + ret = read_poll_timeout(readl, tmp, (tmp & 1) == 0,
> + 20, 10000, false,
> + data->membase +
EMAC_MAC_MIND_REG);
> + if (ret < 0)
> + return ret;
>
> /* push down the phy io line */
> writel(0x0, data->membase + EMAC_MAC_MCMD_REG);
> --
> 2.25.1


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