realtek: avoid busy waiting for RTL839x PHY read/write

Switch to a polling implementation similar to the one for RTL838x, to
allow other kernel tasks to run while waiting.

Signed-off-by: Jan Hoffmann <jan@3e8.eu>

diff --git a/target/linux/realtek/files-5.10/drivers/net/dsa/rtl83xx/rtl839x.c b/target/linux/realtek/files-5.10/drivers/net/dsa/rtl83xx/rtl839x.c
index 199ba347da38026f1220c59e697a440fd1f45d06..29912257e829648402d14d36ba7770af427823ee 100644 (file)
--- a/target/linux/realtek/files-5.10/drivers/net/dsa/rtl83xx/rtl839x.c
+++ b/target/linux/realtek/files-5.10/drivers/net/dsa/rtl83xx/rtl839x.c
@@ -630,9 +630,23 @@ int rtl8390_sds_power(int mac, int val)
        return 0;
 }
 
+static int rtl839x_smi_wait_op(int timeout)
+{
+       int ret = 0;
+       u32 val;
+
+       ret = readx_poll_timeout(sw_r32, RTL839X_PHYREG_ACCESS_CTRL,
+                                val, !(val & 0x1), 20, timeout);
+       if (ret)
+               pr_err("%s: timeout\n", __func__);
+
+       return ret;
+}
+
 int rtl839x_read_phy(u32 port, u32 page, u32 reg, u32 *val)
 {
        u32 v;
+       int err = 0;
 
        if (port > 63 || page > 4095 || reg > 31)
                return -ENOTSUPP;
@@ -652,13 +666,15 @@ int rtl839x_read_phy(u32 port, u32 page, u32 reg, u32 *val)
        v |= 1;
        sw_w32(v, RTL839X_PHYREG_ACCESS_CTRL);
 
-       do {
-       } while (sw_r32(RTL839X_PHYREG_ACCESS_CTRL) & 0x1);
+       err = rtl839x_smi_wait_op(100000);
+       if (err)
+               goto errout;
 
        *val = sw_r32(RTL839X_PHYREG_DATA_CTRL) & 0xffff;
 
+errout:
        mutex_unlock(&smi_lock);
-       return 0;
+       return err;
 }
 
 int rtl839x_write_phy(u32 port, u32 page, u32 reg, u32 val)
@@ -689,12 +705,14 @@ int rtl839x_write_phy(u32 port, u32 page, u32 reg, u32 val)
        v |= BIT(3) | 1; /* Write operation and execute */
        sw_w32(v, RTL839X_PHYREG_ACCESS_CTRL);
 
-       do {
-       } while (sw_r32(RTL839X_PHYREG_ACCESS_CTRL) & 0x1);
+       err = rtl839x_smi_wait_op(100000);
+       if (err)
+               goto errout;
 
        if (sw_r32(RTL839X_PHYREG_ACCESS_CTRL) & 0x2)
                err = -EIO;
 
+errout:
        mutex_unlock(&smi_lock);
        return err;
 }
@@ -722,15 +740,16 @@ int rtl839x_read_mmd_phy(u32 port, u32 devnum, u32 regnum, u32 *val)
        v = BIT(2) | BIT(0); // MMD-access | EXEC
        sw_w32(v, RTL839X_PHYREG_ACCESS_CTRL);
 
-       do {
-               v = sw_r32(RTL839X_PHYREG_ACCESS_CTRL);
-       } while (v & BIT(0));
+       err = rtl839x_smi_wait_op(100000);
+       if (err)
+               goto errout;
+
        // There is no error-checking via BIT 1 of v, as it does not seem to be set correctly
        *val = (sw_r32(RTL839X_PHYREG_DATA_CTRL) & 0xffff);
        pr_debug("%s: port %d, regnum: %x, val: %x (err %d)\n", __func__, port, regnum, *val, err);
 
+errout:
        mutex_unlock(&smi_lock);
-
        return err;
 }
 
@@ -760,11 +779,13 @@ int rtl839x_write_mmd_phy(u32 port, u32 devnum, u32 regnum, u32 val)
        v = BIT(3) | BIT(2) | BIT(0); // WRITE | MMD-access | EXEC
        sw_w32(v, RTL839X_PHYREG_ACCESS_CTRL);
 
-       do {
-               v = sw_r32(RTL839X_PHYREG_ACCESS_CTRL);
-       } while (v & BIT(0));
+       err = rtl839x_smi_wait_op(100000);
+       if (err)
+               goto errout;
 
        pr_debug("%s: port %d, regnum: %x, val: %x (err %d)\n", __func__, port, regnum, val, err);
+
+errout:
        mutex_unlock(&smi_lock);
        return err;
 }