Hi Harini,
On 26.11.2018 09:07, Harini Katakam wrote:
> From: Harini Katakam <hari...@xilinx.com>
>
> Replace the while loop in MDIO read/write functions with a timeout.
> In addition, add a check for MDIO bus busy before initiating a new
> operation as well to make sure there is no ongoing MDIO operation.
Is this MDIO bus busy check necessary? The caller of
macb_mdio_read/macb_mdio_write locks the mdio bus mutex before calling it
(e.g. mdiobus_read).
>
> Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.da...@xilinx.com>
> Signed-off-by: Sai Pavan Boddu <sai.pavan.bo...@xilinx.com>
> Signed-off-by: Harini Katakam <hari...@xilinx.com>
> ---
> v2 changes:
> Use readx_poll_timeout
>
> Changes form RFC:
> Cleaned up timeout implementation and moved it to a helper.
>
> drivers/net/ethernet/cadence/macb.h | 3 +++
> drivers/net/ethernet/cadence/macb_main.c | 33
> ++++++++++++++++++++++++++------
> 2 files changed, 30 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/ethernet/cadence/macb.h
> b/drivers/net/ethernet/cadence/macb.h
> index 3d45f4c..df7bee1 100644
> --- a/drivers/net/ethernet/cadence/macb.h
> +++ b/drivers/net/ethernet/cadence/macb.h
> @@ -714,6 +714,9 @@
> __v; \
> })
>
> +#define MACB_IDLE_MASK (1 << MACB_IDLE_OFFSET)
You could use MACB_BIT(IDLE) instead.
> +#define MACB_READ_NSR(bp) macb_readl(bp, NSR)
Is this necessary?
> +
> /* struct macb_dma_desc - Hardware DMA descriptor
> * @addr: DMA address of data buffer
> * @ctrl: Control and status bits
> diff --git a/drivers/net/ethernet/cadence/macb_main.c
> b/drivers/net/ethernet/cadence/macb_main.c
> index 1d86b4d..fd86ece 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -36,6 +36,7 @@
> #include <linux/ip.h>
> #include <linux/udp.h>
> #include <linux/tcp.h>
> +#include <linux/iopoll.h>
> #include "macb.h"
>
> #define MACB_RX_BUFFER_SIZE 128
> @@ -79,6 +80,8 @@
> */
> #define MACB_HALT_TIMEOUT 1230
>
> +#define MACB_MDIO_TIMEOUT 1000000 /* in usecs */
> +
> /* DMA buffer descriptor might be different size
> * depends on hardware configuration:
> *
> @@ -318,10 +321,23 @@ static void macb_get_hwaddr(struct macb *bp)
> eth_hw_addr_random(bp->dev);
> }
>
> +static int macb_mdio_wait_for_idle(struct macb *bp)
> +{
> + u32 val;
> +
> + return readx_poll_timeout(MACB_READ_NSR, bp, val, val & MACB_IDLE_MASK,
> + 1, MACB_MDIO_TIMEOUT);
> +}
> +
> static int macb_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
> {
> struct macb *bp = bus->priv;
> int value;
> + int err;
> +
> + err = macb_mdio_wait_for_idle(bp);
> + if (err < 0)
> + return err;
>
> macb_writel(bp, MAN, (MACB_BF(SOF, MACB_MAN_SOF)
> | MACB_BF(RW, MACB_MAN_READ)
> @@ -329,9 +345,9 @@ static int macb_mdio_read(struct mii_bus *bus, int
> mii_id, int regnum)
> | MACB_BF(REGA, regnum)
> | MACB_BF(CODE, MACB_MAN_CODE)));
>
> - /* wait for end of transfer */
> - while (!MACB_BFEXT(IDLE, macb_readl(bp, NSR)))
> - cpu_relax();
> + err = macb_mdio_wait_for_idle(bp);
> + if (err < 0)
> + return err;
>
> value = MACB_BFEXT(DATA, macb_readl(bp, MAN));
>
> @@ -342,6 +358,11 @@ static int macb_mdio_write(struct mii_bus *bus, int
> mii_id, int regnum,
> u16 value)
> {
> struct macb *bp = bus->priv;
> + int err;
> +
> + err = macb_mdio_wait_for_idle(bp);
> + if (err < 0)
> + return err;
>
> macb_writel(bp, MAN, (MACB_BF(SOF, MACB_MAN_SOF)
> | MACB_BF(RW, MACB_MAN_WRITE)
> @@ -350,9 +371,9 @@ static int macb_mdio_write(struct mii_bus *bus, int
> mii_id, int regnum,
> | MACB_BF(CODE, MACB_MAN_CODE)
> | MACB_BF(DATA, value)));
>
> - /* wait for end of transfer */
> - while (!MACB_BFEXT(IDLE, macb_readl(bp, NSR)))
> - cpu_relax();
> + err = macb_mdio_wait_for_idle(bp);
> + if (err < 0)
> + return err;
>
> return 0;
> }
>
