[RFC PATCH v2] net: phy: Added device tree binding for dev-addr and dev-addr code check-up

From: Vicentiu Galanopulo
Date: Fri Mar 23 2018 - 11:05:52 EST

Reason for this patch is that the Inphi PHY has a
vendor specific address space for accessing the
C45 MDIO registers - starting from 0x1e.

A search of the dev-addr property is done in of_mdiobus_register.
If the property is found in the PHY node,
of_mdiobus_register_static_phy is called. This is a
wrapper function for of_mdiobus_register_phy which finds the
device in package based on dev-addr and fills devices_addrs:
devices_addrs is a new field added to phy_c45_device_ids.
This new field will store the dev-addr property on the same
index where the device in package has been found.
In order to have dev-addr in get_phy_c45_ids(), mdio_c45_ids is
passed from of_mdio.c to phy_device.c as an external variable.
In get_phy_device a copy of the mdio_c45_ids is done over the
local c45_ids (wich are empty). After the copying, the c45_ids
will also contain the static device found from dev-addr.
Having dev-addr stored in devices_addrs, in get_phy_c45_ids(),
when probing the identifiers, dev-addr can be extracted from
devices_addrs and probed if devices_addrs[current_identifier]
is not 0.
This way changing the kernel API is avoided completely.

As a plus to this patch, num_ids in get_phy_c45_ids,
has the value 8 (ARRAY_SIZE(c45_ids->device_ids)),
but the u32 *devs can store 32 devices in the bitfield.
If a device is stored in *devs, in bits 32 to 9, it
will not be found. This is the reason for changing
in phy.h, the size of device_ids array.

Signed-off-by: Vicentiu Galanopulo <vicentiu.galanopulo@xxxxxxx>
---
Documentation/devicetree/bindings/net/phy.txt | 6 ++
drivers/net/phy/phy_device.c | 22 +++++-
drivers/of/of_mdio.c | 98 ++++++++++++++++++++++++++-
include/linux/phy.h | 5 +-
4 files changed, 125 insertions(+), 6 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/phy.txt b/Documentation/devicetree/bindings/net/phy.txt
index d2169a5..82692e2 100644
--- a/Documentation/devicetree/bindings/net/phy.txt
+++ b/Documentation/devicetree/bindings/net/phy.txt
@@ -61,6 +61,11 @@ Optional Properties:
- reset-deassert-us: Delay after the reset was deasserted in microseconds.
If this property is missing the delay will be skipped.

+- dev-addr: If set, it indicates the device address of the PHY to be used
+ when accessing the C45 PHY registers over MDIO. It is used for vendor specific
+ register space addresses that do no conform to standard address for the MDIO
+ registers (e.g. MMD30)
+
Example:

ethernet-phy@0 {
@@ -72,4 +77,5 @@ ethernet-phy@0 {
reset-gpios = <&gpio1 4 GPIO_ACTIVE_LOW>;
reset-assert-us = <1000>;
reset-deassert-us = <2000>;
+ dev-addr = <0x1e>;
};
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index b285323..f5051cf6 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -71,6 +71,7 @@ static void phy_mdio_device_remove(struct mdio_device *mdiodev)

static struct phy_driver genphy_driver;
extern struct phy_driver genphy_10g_driver;
+extern struct phy_c45_device_ids mdio_c45_ids;

static LIST_HEAD(phy_fixup_list);
static DEFINE_MUTEX(phy_fixup_lock);
@@ -457,7 +458,7 @@ static int get_phy_c45_devs_in_pkg(struct mii_bus *bus, int addr, int dev_addr,
static int get_phy_c45_ids(struct mii_bus *bus, int addr, u32 *phy_id,
struct phy_c45_device_ids *c45_ids) {
int phy_reg;
- int i, reg_addr;
+ int i, reg_addr, dev_addr;
const int num_ids = ARRAY_SIZE(c45_ids->device_ids);
u32 *devs = &c45_ids->devices_in_package;

@@ -493,13 +494,23 @@ static int get_phy_c45_ids(struct mii_bus *bus, int addr, u32 *phy_id,
if (!(c45_ids->devices_in_package & (1 << i)))
continue;

- reg_addr = MII_ADDR_C45 | i << 16 | MII_PHYSID1;
+ /* if c45_ids->devices_addrs for the current id is not 0,
+ * then dev-addr was defined in the device tree node,
+ * and the PHY as been seen as a valid device, and added,
+ * in the package. In this case we can use the
+ * dev-addr(c45_ids->devices_addrs[i]) to do the MDIO
+ * reading of the PHY ID.
+ */
+ dev_addr = !!c45_ids->devices_addrs[i] ?
+ c45_ids->devices_addrs[i] : i;
+
+ reg_addr = MII_ADDR_C45 | dev_addr << 16 | MII_PHYSID1;
phy_reg = mdiobus_read(bus, addr, reg_addr);
if (phy_reg < 0)
return -EIO;
c45_ids->device_ids[i] = (phy_reg & 0xffff) << 16;

- reg_addr = MII_ADDR_C45 | i << 16 | MII_PHYSID2;
+ reg_addr = MII_ADDR_C45 | dev_addr << 16 | MII_PHYSID2;
phy_reg = mdiobus_read(bus, addr, reg_addr);
if (phy_reg < 0)
return -EIO;
@@ -566,6 +577,11 @@ struct phy_device *get_phy_device(struct mii_bus *bus, int addr, bool is_c45)
u32 phy_id = 0;
int r;

+ /* copy the external mdio_c45_ids (which may contain the id's found
+ * by serching the device tree dev-addr property) to local c45_ids
+ */
+ memcpy(&c45_ids, &mdio_c45_ids, sizeof(struct phy_c45_device_ids));
+
r = get_phy_id(bus, addr, &phy_id, is_c45, &c45_ids);
if (r)
return ERR_PTR(r);
diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
index 8c0c927..cbc34f6 100644
--- a/drivers/of/of_mdio.c
+++ b/drivers/of/of_mdio.c
@@ -24,6 +24,8 @@

#define DEFAULT_GPIO_RESET_DELAY 10 /* in microseconds */

+struct phy_c45_device_ids mdio_c45_ids = {0};
+
MODULE_AUTHOR("Grant Likely <grant.likely@xxxxxxxxxxxx>");
MODULE_LICENSE("GPL");

@@ -190,6 +192,71 @@ static bool of_mdiobus_child_is_phy(struct device_node *child)
return false;
}

+static void of_fill_c45ids_devs_addrs(u32 dev_addr)
+{
+ int i;
+ const int num_ids = ARRAY_SIZE(mdio_c45_ids.device_ids);
+
+ /* Search through all Device Identifiers and set
+ * dev_addr in mdio_c45_ids.devices_addrs,
+ * if the device bit is set in
+ * mdio_c45_ids.devices_in_package
+ */
+ for (i = 1; i < num_ids; i++) {
+ if (!(mdio_c45_ids.devices_in_package & (1 << i)))
+ continue;
+
+ mdio_c45_ids.devices_addrs[i] = dev_addr;
+ break;
+ }
+}
+
+static int of_find_devaddr_in_pkg(struct mii_bus *bus, u32 addr,
+ u32 dev_addr)
+{
+ u32 *devs = &mdio_c45_ids.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;
+
+ *devs = (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;
+
+ *devs |= (phy_reg & 0xffff);
+
+ return 0;
+}
+
+/*
+ * Finds the device in package and populates the mdio_c45_ids
+ * if any device is found at dev_addr address. After this
+ * the PHY is registered
+ */
+static int of_mdiobus_register_static_phy(struct mii_bus *mdio,
+ struct device_node *child,
+ u32 addr, u32 dev_addr)
+{
+ int dev_err = 0;
+
+ if (!dev_addr)
+ goto exit_register_phy;
+
+ dev_err = of_find_devaddr_in_pkg(mdio, addr, dev_addr);
+
+ if (!dev_err)
+ of_fill_c45ids_devs_addrs(dev_addr);
+
+exit_register_phy:
+ return of_mdiobus_register_phy(mdio, child, addr);
+}
+
/**
* of_mdiobus_register - Register mii_bus and create PHYs from the device tree
* @mdio: pointer to mii_bus structure
@@ -202,7 +269,10 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
{
struct device_node *child;
bool scanphys = false;
+ bool dev_addr_found = true;
int addr, rc;
+ int dev_addr = 0;
+ int ret;

/* Do not continue if the node is disabled */
if (!of_device_is_available(np))
@@ -226,6 +296,14 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)

/* Loop over the child nodes and register a phy_device for each phy */
for_each_available_child_of_node(np, child) {
+ /* Check if dev-addr is set in the PHY node */
+ ret = of_property_read_u32(child, "dev-addr", &dev_addr);
+
+ if (ret < 0) {
+ /* either not set or invalid */
+ dev_addr_found = false;
+ }
+
addr = of_mdio_parse_addr(&mdio->dev, child);
if (addr < 0) {
scanphys = true;
@@ -233,7 +311,11 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
}

if (of_mdiobus_child_is_phy(child))
- rc = of_mdiobus_register_phy(mdio, child, addr);
+ if (dev_addr_found)
+ rc = of_mdiobus_register_static_phy(mdio, child,
+ addr, dev_addr);
+ else
+ rc = of_mdiobus_register_phy(mdio, child, addr);
else
rc = of_mdiobus_register_device(mdio, child, addr);

@@ -248,8 +330,16 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
if (!scanphys)
return 0;

+ /* reset device found variable */
+ dev_addr_found = true;
+
/* auto scan for PHYs with empty reg property */
for_each_available_child_of_node(np, child) {
+ /* Check if dev-addr is set in the PHY node,
+ * for PHYs which don't have reg property set
+ */
+ ret = of_property_read_u32(child, "dev-addr", &dev_addr);
+
/* Skip PHYs with reg property set */
if (of_find_property(child, "reg", NULL))
continue;
@@ -264,7 +354,11 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
child->name, addr);

if (of_mdiobus_child_is_phy(child)) {
- rc = of_mdiobus_register_phy(mdio, child, addr);
+ if (dev_addr_found)
+ rc = of_mdiobus_register_static_phy(mdio, child,
+ addr, dev_addr);
+ else
+ rc = of_mdiobus_register_phy(mdio, child, addr);
if (rc && rc != -ENODEV)
goto unregister;
}
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 5a9b175..161ad90 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -357,10 +357,13 @@ enum phy_state {
* struct phy_c45_device_ids - 802.3-c45 Device Identifiers
* @devices_in_package: Bit vector of devices present.
* @device_ids: The device identifer for each present device.
+ * @devices_addrs: The devices addresses from the device tree
+ * for each present device.
*/
struct phy_c45_device_ids {
u32 devices_in_package;
- u32 device_ids[8];
+ u32 device_ids[32];
+ u32 devices_addrs[32];
};

/* phy_device: An instance of a PHY
--
2.7.4