target/linux/generic/pending-6.1/726-net-phy-realtek-make-sure-paged-read-is-protected-by.patch

   1 From 4dd2cc9b91ecb25f278a2c55e07e6455e9000e6b Mon Sep 17 00:00:00 2001
   2 From: Daniel Golle <daniel@makrotopia.org>
   3 Date: Sat, 22 Apr 2023 01:21:14 +0100
   4 Subject: [PATCH] net: phy: realtek: make sure paged read is protected by mutex
   5
   6 As we cannot rely on phy_read_paged function before the PHY is
   7 identified, the paged read in rtlgen_supports_2_5gbps needs to be open
   8 coded as it is being called by the match_phy_device function, ie. before
   9 .read_page and .write_page have been populated.
  10
  11 Make sure it is also protected by the MDIO bus mutex and use
  12 rtl821x_write_page instead of 3 individually locked MDIO bus operations.
  13
  14 Signed-off-by: Daniel Golle <daniel@makrotopia.org>
  15 ---
  16  drivers/net/phy/realtek.c | 8 +++++---
  17  1 file changed, 5 insertions(+), 3 deletions(-)
  18
  19 --- a/drivers/net/phy/realtek.c
  20 +++ b/drivers/net/phy/realtek.c
  21 @@ -737,9 +737,11 @@ static bool rtlgen_supports_2_5gbps(stru
  22  {
  23         int val;
  24
  25 -       phy_write(phydev, RTL821x_PAGE_SELECT, 0xa61);
  26 -       val = phy_read(phydev, 0x13);
  27 -       phy_write(phydev, RTL821x_PAGE_SELECT, 0);
  28 +       mutex_lock(&phydev->mdio.bus->mdio_lock);
  29 +       rtl821x_write_page(phydev, 0xa61);
  30 +       val = __phy_read(phydev, 0x13);
  31 +       rtl821x_write_page(phydev, 0);
  32 +       mutex_unlock(&phydev->mdio.bus->mdio_lock);
  33
  34         return val >= 0 && val & RTL_SUPPORTS_2500FULL;
  35  }