PCI: brcmstb: Make two changes in MDIO register fields

The hardware has been updated with two changes to the MDIO packet
format.

The CMD field used to be 12 bits and now is only 1 bit. This change
is backwards compatible because the field's starting bit position is
unchanged, and the only commands we've used have values 0 and 1.

The PORT field's width has been changed from 4 bits to 5 bits. When
written, the new bit is not contiguous with the other four. However,
this change is backwards compatible because the driver never used
anything other than 0 for the port field's value.

Thus, update the existing code to handle new changes to the hardware
in a backwards-compatible manner.

Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20250214173944.47506-8-james.quinlan@broadcom.com
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 76f51352709e913a67b2d249fb1e907735df7912..ab25f674800d3c0e51b4217679be9b4719f18e39 100644 (file)
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -175,8 +175,9 @@
 #define MDIO_PORT0                     0x0
 #define MDIO_DATA_MASK                 0x7fffffff
 #define MDIO_PORT_MASK                 0xf0000
+#define MDIO_PORT_EXT_MASK             0x200000
 #define MDIO_REGAD_MASK                        0xffff
-#define MDIO_CMD_MASK                  0xfff00000
+#define MDIO_CMD_MASK                  0x00100000
 #define MDIO_CMD_READ                  0x1
 #define MDIO_CMD_WRITE                 0x0
 #define MDIO_DATA_DONE_MASK            0x80000000
@@ -327,6 +328,7 @@ static u32 brcm_pcie_mdio_form_pkt(int port, int regad, int cmd)
 {
        u32 pkt = 0;
 
+       pkt |= FIELD_PREP(MDIO_PORT_EXT_MASK, port >> 4);
        pkt |= FIELD_PREP(MDIO_PORT_MASK, port);
        pkt |= FIELD_PREP(MDIO_REGAD_MASK, regad);
        pkt |= FIELD_PREP(MDIO_CMD_MASK, cmd);