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

On 20.08.19 04:08, Andy Duan wrote:

From: Marco Hartmann Sent: Tuesday, August 20, 2019 1:11 AM

quoted

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 <redacted>
Signed-off-by: Christian Herber <redacted>
Signed-off-by: Marco Hartmann <redacted>
---
  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);

quoted

  	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)

quoted

+		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;

quoted

+		}
+
+		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);

quoted

  	reinit_completion(&fep->mdio_done);

+	if (MII_ADDR_C45 & regnum) {

if (!is_c45) {

quoted

+		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;

quoted

+		}
+	} 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

Thank you for your feedback,
the fixes are included in v2 of the patch.

Regards,
Marco