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Commit 5f6c99e0 authored by Shaohui Xie's avatar Shaohui Xie Committed by David S. Miller
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net: phy: fix a bug in get_phy_c45_ids 



When probing devices-in-package for a c45 phy, device zero is the last
device to probe, however, if driver reads 0 from device zero,
c45_ids->devices_in_package is set to '0', the loop condition of probing
will be matched again, see codes below:

for (i = 1;i < num_ids && c45_ids->devices_in_package == 0;i++)

driver will run in a dead loop.

This patch restructures the bug and confusing loop, it provides a helper
function get_phy_c45_devs_in_pkg which to read devices-in-package registers
of a MMD, and rewrites the loop with using the helper function.

Signed-off-by: default avatarShaohui Xie <Shaohui.Xie@freescale.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b2663a4f

drivers/net/phy/phy_device.c

+49 −25
Original line number Diff line number Diff line
@@ -205,6 +205,37 @@ struct phy_device *phy_device_create(struct mii_bus *bus, int addr, int phy_id, 
}

EXPORT_SYMBOL(phy_device_create);



/* get_phy_c45_devs_in_pkg - reads a MMD's devices in package registers.

 * @bus: the target MII bus

 * @addr: PHY address on the MII bus

 * @dev_addr: MMD address in the PHY.

 * @devices_in_package: where to store the devices in package information.

 *

 * Description: reads devices in package registers of a MMD at @dev_addr

 * from PHY at @addr on @bus.

 *

 * Returns: 0 on success, -EIO on failure.

 */

static int get_phy_c45_devs_in_pkg(struct mii_bus *bus, int addr, int dev_addr,

				   u32 *devices_in_package)

{

	int phy_reg, reg_addr;



	reg_addr = MII_ADDR_C45 | dev_addr << 16 | MDIO_DEVS2;

	phy_reg = mdiobus_read(bus, addr, reg_addr);

	if (phy_reg < 0)

		return -EIO;

	*devices_in_package = (phy_reg & 0xffff) << 16;



	reg_addr = MII_ADDR_C45 | dev_addr << 16 | MDIO_DEVS1;

	phy_reg = mdiobus_read(bus, addr, reg_addr);

	if (phy_reg < 0)

		return -EIO;

	*devices_in_package |= (phy_reg & 0xffff);



	return 0;

}



/**

 * get_phy_c45_ids - reads the specified addr for its 802.3-c45 IDs.

 * @bus: the target MII bus
@@ -223,38 +254,31 @@ static int get_phy_c45_ids(struct mii_bus *bus, int addr, u32 *phy_id, 
	int phy_reg;

	int i, reg_addr;

	const int num_ids = ARRAY_SIZE(c45_ids->device_ids);

	u32 *devs = &c45_ids->devices_in_package;



	/* Find first non-zero Devices In package.  Device

	 * zero is reserved, so don't probe it.

	/* Find first non-zero Devices In package. Device zero is reserved

	 * for 802.3 c45 complied PHYs, so don't probe it at first.

	 */

	for (i = 1;

	     i < num_ids && c45_ids->devices_in_package == 0;

	     i++) {

retry:		reg_addr = MII_ADDR_C45 | i << 16 | MDIO_DEVS2;

		phy_reg = mdiobus_read(bus, addr, reg_addr);

		if (phy_reg < 0)

			return -EIO;

		c45_ids->devices_in_package = (phy_reg & 0xffff) << 16;



		reg_addr = MII_ADDR_C45 | i << 16 | MDIO_DEVS1;

		phy_reg = mdiobus_read(bus, addr, reg_addr);

	for (i = 1; i < num_ids && *devs == 0; i++) {

		phy_reg = get_phy_c45_devs_in_pkg(bus, addr, i, devs);

		if (phy_reg < 0)

			return -EIO;

		c45_ids->devices_in_package |= (phy_reg & 0xffff);



		if ((c45_ids->devices_in_package & 0x1fffffff) == 0x1fffffff) {

			if (i) {

		if ((*devs & 0x1fffffff) == 0x1fffffff) {

			/*  If mostly Fs, there is no device there,

			 *  then let's continue to probe more, as some

			 *  10G PHYs have zero Devices In package,

			 *  e.g. Cortina CS4315/CS4340 PHY.

			 */

				i = 0;

				goto retry;

			} else {

			phy_reg = get_phy_c45_devs_in_pkg(bus, addr, 0, devs);

			if (phy_reg < 0)

				return -EIO;

			/* no device there, let's get out of here */

			if ((*devs & 0x1fffffff) == 0x1fffffff) {

				*phy_id = 0xffffffff;

				return 0;

			} else {

				break;

			}

		}

	}