netdev - RE: [PATCH net-next 1/1] fec: add C45 MDIO read/write support

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Date:   Tue, 20 Aug 2019 02:08:12 +0000
From:   Andy Duan <fugang.duan@....com>
To:     Marco Hartmann <marco.hartmann@....com>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Christian Herber <christian.herber@....com>
Subject: RE: [PATCH net-next 1/1] fec: add C45 MDIO read/write support

From: Marco Hartmann Sent: Tuesday, August 20, 2019 1:11 AM
> IEEE 802.3ae clause 45 defines a modified MDIO protocol that uses a two
> staged access model in order to increase the address space.
> 
> This patch adds support for C45 MDIO read and write accesses, which are
> used whenever the MII_ADDR_C45 flag in the regnum argument is set.
> In case it is not set, C22 accesses are used as before.
> 
> Co-developed-by: Christian Herber <christian.herber@....com>
> Signed-off-by: Christian Herber <christian.herber@....com>
> Signed-off-by: Marco Hartmann <marco.hartmann@....com>
> ---
>  drivers/net/ethernet/freescale/fec_main.c | 65
> ++++++++++++++++++++++++++++---
>  1 file changed, 59 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/freescale/fec_main.c
> b/drivers/net/ethernet/freescale/fec_main.c
> index c01d3ec3e9af..73f8f9a149a1 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -208,8 +208,11 @@ MODULE_PARM_DESC(macaddr, "FEC Ethernet
> MAC address");
> 
>  /* FEC MII MMFR bits definition */
>  #define FEC_MMFR_ST		(1 << 30)
> +#define FEC_MMFR_ST_C45		(0)
>  #define FEC_MMFR_OP_READ	(2 << 28)
> +#define FEC_MMFR_OP_READ_C45	(3 << 28)
>  #define FEC_MMFR_OP_WRITE	(1 << 28)
> +#define FEC_MMFR_OP_ADDR_WRITE	(0)
>  #define FEC_MMFR_PA(v)		((v & 0x1f) << 23)
>  #define FEC_MMFR_RA(v)		((v & 0x1f) << 18)
>  #define FEC_MMFR_TA		(2 << 16)
> @@ -1767,7 +1770,7 @@ static int fec_enet_mdio_read(struct mii_bus *bus,
> int mii_id, int regnum)
>  	struct fec_enet_private *fep = bus->priv;
>  	struct device *dev = &fep->pdev->dev;
>  	unsigned long time_left;
> -	int ret = 0;
> +	int ret = 0, frame_start, frame_addr, frame_op;

Add bool variable:

bool is_c45 = !!(regnum & MII_ADDR_C45);
> 
>  	ret = pm_runtime_get_sync(dev);
>  	if (ret < 0)
> @@ -1775,9 +1778,36 @@ static int fec_enet_mdio_read(struct mii_bus
> *bus, int mii_id, int regnum)
> 
>  	reinit_completion(&fep->mdio_done);
> 
> +	if (MII_ADDR_C45 & regnum) {
if (is_c45)

> +		frame_start = FEC_MMFR_ST_C45;
> +
> +		/* write address */
> +		frame_addr = (regnum >> 16);
> +		writel(frame_start | FEC_MMFR_OP_ADDR_WRITE |
> +		       FEC_MMFR_PA(mii_id) | FEC_MMFR_RA(frame_addr) |
> +		       FEC_MMFR_TA | (regnum & 0xFFFF),
> +		       fep->hwp + FEC_MII_DATA);
> +
> +		/* wait for end of transfer */
> +		time_left = wait_for_completion_timeout(&fep->mdio_done,
> +				usecs_to_jiffies(FEC_MII_TIMEOUT));
> +		if (time_left == 0) {
> +			netdev_err(fep->netdev, "MDIO address write timeout\n");
> +			ret  = -ETIMEDOUT;

Should be:
goto out;
> +		}
> +
> +		frame_op = FEC_MMFR_OP_READ_C45;
> +
> +	} else {
> +		/* C22 read */
> +		frame_op = FEC_MMFR_OP_READ;
> +		frame_start = FEC_MMFR_ST;
> +		frame_addr = regnum;
> +	}
> +
>  	/* start a read op */
> -	writel(FEC_MMFR_ST | FEC_MMFR_OP_READ |
> -		FEC_MMFR_PA(mii_id) | FEC_MMFR_RA(regnum) |
> +	writel(frame_start | frame_op |
> +		FEC_MMFR_PA(mii_id) | FEC_MMFR_RA(frame_addr) |
>  		FEC_MMFR_TA, fep->hwp + FEC_MII_DATA);
> 
>  	/* wait for end of transfer */
> @@ -1804,7 +1834,7 @@ static int fec_enet_mdio_write(struct mii_bus *bus,
> int mii_id, int regnum,
>  	struct fec_enet_private *fep = bus->priv;
>  	struct device *dev = &fep->pdev->dev;
>  	unsigned long time_left;
> -	int ret;
> +	int ret, frame_start, frame_addr;
> 
>  	ret = pm_runtime_get_sync(dev);
>  	if (ret < 0)
> @@ -1814,9 +1844,32 @@ static int fec_enet_mdio_write(struct mii_bus
> *bus, int mii_id, int regnum,

bool is_c45 = !!(regnum & MII_ADDR_C45);
> 
>  	reinit_completion(&fep->mdio_done);
> 
> +	if (MII_ADDR_C45 & regnum) {

if (!is_c45) {
> +		frame_start = FEC_MMFR_ST_C45;
> +
> +		/* write address */
> +		frame_addr = (regnum >> 16);
> +		writel(frame_start | FEC_MMFR_OP_ADDR_WRITE |
> +		       FEC_MMFR_PA(mii_id) | FEC_MMFR_RA(frame_addr) |
> +		       FEC_MMFR_TA | (regnum & 0xFFFF),
> +		       fep->hwp + FEC_MII_DATA);
> +
> +		/* wait for end of transfer */
> +		time_left = wait_for_completion_timeout(&fep->mdio_done,
> +			usecs_to_jiffies(FEC_MII_TIMEOUT));
> +		if (time_left == 0) {
> +			netdev_err(fep->netdev, "MDIO address write timeout\n");
> +			ret  = -ETIMEDOUT;
Like mdio read, it should be:
goto out; 
> +		}
> +	} else {
> +		/* C22 write */
> +		frame_start = FEC_MMFR_ST;
> +		frame_addr = regnum;
> +	}
> +
>  	/* start a write op */
> -	writel(FEC_MMFR_ST | FEC_MMFR_OP_WRITE |
> -		FEC_MMFR_PA(mii_id) | FEC_MMFR_RA(regnum) |
> +	writel(frame_start | FEC_MMFR_OP_WRITE |
> +		FEC_MMFR_PA(mii_id) | FEC_MMFR_RA(frame_addr) |
>  		FEC_MMFR_TA | FEC_MMFR_DATA(value),
>  		fep->hwp + FEC_MII_DATA);
> 
> --
> 2.7.4