net: mdio: realtek-rtl9300: Add pages to info structure

The Realtek ethernet MDIO controller has a proprietary paging feature
that is closely aligned with Realtek based PHYs. These PHY know "pages"
for C22 access. Those can be switched via reads/writes to register 31.
Usually the paged access must be programmed in four steps.

1. read/save page register
2. change "page" register 31
3. read/write data register (on the given page)
4. restore page register

The controller can run all this in hardware with one single request
from the driver. It is given the page, the register and the data
and takes care of all the rest. This reduces CPU load. The number
of supported pages depend on the model. This is either 4096 for low
port count SOCs (up to 28 ports) or 8192 for high port count SOCs
(up to 56 ports).

There is however one special page that allows to pass through all C22
commands directly to the PHY - without any caching. This so called raw
page is dependent of the hardware. It is the highest supported page
number minus 1.

Provide the number of supported pages as a device specific property.
This new "num_pages" aligns with the existing properties and gives
an better insight into the hardware layout than just defining the
number of the raw page. The later directly derives from that and
can be accessed with the new RAW_PAGE() macro. Make use of it where
needed.

Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://patch.msgid.link/20260521175918.1494797-5-markus.stockhausen@gmx.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/mdio/mdio-realtek-rtl9300.c b/drivers/net/mdio/mdio-realtek-rtl9300.c
index 941e557bc0e238de7cfc5c5da48f108a7972a32f..94f59a56bc4667d777f3c5f7a71abef1b358df3d 100644 (file)
--- a/drivers/net/mdio/mdio-realtek-rtl9300.c
+++ b/drivers/net/mdio/mdio-realtek-rtl9300.c
@@ -52,6 +52,7 @@
 #include <linux/regmap.h>
 
 #define RTL9300_NUM_BUSES              4
+#define RTL9300_NUM_PAGES              4096
 #define RTL9300_NUM_PORTS              28
 #define SMI_GLB_CTRL                   0xca00
 #define   GLB_CTRL_INTF_SEL(intf)      BIT(16 + (intf))
@@ -78,10 +79,12 @@
 #define MAX_PORTS       28
 #define MAX_SMI_BUSSES  4
 #define MAX_SMI_ADDR   0x1f
+#define RAW_PAGE(priv) ((priv)->info->num_pages - 1)
 
 struct otto_emdio_info {
        u8 num_buses;
        u8 num_ports;
+       u16 num_pages;
 };
 
 struct otto_emdio_priv {
@@ -154,7 +157,7 @@ static int otto_emdio_9300_read_c22(struct mii_bus *bus, int phy_id, int regnum)
 
        val = FIELD_PREP(PHY_CTRL_REG_ADDR, regnum) |
              FIELD_PREP(PHY_CTRL_PARK_PAGE, 0x1f) |
-             FIELD_PREP(PHY_CTRL_MAIN_PAGE, 0xfff) |
+             FIELD_PREP(PHY_CTRL_MAIN_PAGE, RAW_PAGE(priv)) |
              PHY_CTRL_READ | PHY_CTRL_TYPE_C22 | PHY_CTRL_CMD;
        err = regmap_write(regmap, SMI_ACCESS_PHY_CTRL_1, val);
        if (err)
@@ -207,7 +210,7 @@ static int otto_emdio_9300_write_c22(struct mii_bus *bus, int phy_id, int regnum
 
        val = FIELD_PREP(PHY_CTRL_REG_ADDR, regnum) |
              FIELD_PREP(PHY_CTRL_PARK_PAGE, 0x1f) |
-             FIELD_PREP(PHY_CTRL_MAIN_PAGE, 0xfff) |
+             FIELD_PREP(PHY_CTRL_MAIN_PAGE, RAW_PAGE(priv)) |
              PHY_CTRL_WRITE | PHY_CTRL_TYPE_C22 | PHY_CTRL_CMD;
        err = regmap_write(regmap, SMI_ACCESS_PHY_CTRL_1, val);
        if (err)
@@ -540,6 +543,7 @@ static int otto_emdio_probe(struct platform_device *pdev)
 static const struct otto_emdio_info otto_emdio_9300_info = {
        .num_buses = RTL9300_NUM_BUSES,
        .num_ports = RTL9300_NUM_PORTS,
+       .num_pages = RTL9300_NUM_PAGES,
 };
 
 static const struct of_device_id otto_emdio_ids[] = {