PCI: aardvark: Fix reporting Slot capabilities on emulated bridge

[ Upstream commit bcdb6fd4f3e9ac1097698c8d8f56b70853b49873 ]

Slot capabilities are currently not reported because emulated bridge does
not report the PCI_EXP_FLAGS_SLOT flag.

Set PCI_EXP_FLAGS_SLOT to let the kernel know that PCI_EXP_SLT* registers
are supported.

Move setting of PCI_EXP_SLTCTL register from "dynamic" pcie_conf_read
function to static buffer as it is only statically filled the
PCI_EXP_SLTSTA_PDS flag and dynamic read callback is not needed for this
register.

Set Presence State Bit to 1 since there is no support for unplugging the
card and there is currently no platform able to detect presence of a card -
in such a case the bit needs to be set to 1.

Finally correctly set Physical Slot Number to 1 since there is only one
port and zero value is reserved for ports within the same silicon as Root
Port which is not our case for Aardvark HW.

Link: https://lore.kernel.org/r/20220524132827.8837-3-kabel@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 7cc2c54..215f751 100644 (file)
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -8,6 +8,7 @@
  * Author: Hezi Shahmoon <hezi.shahmoon@marvell.com>
  */
 
+#include <linux/bitfield.h>
 #include <linux/delay.h>
 #include <linux/gpio/consumer.h>
 #include <linux/interrupt.h>
@@ -857,14 +858,11 @@ advk_pci_bridge_emul_pcie_conf_read(struct pci_bridge_emul *bridge,
 
 
        switch (reg) {
-       case PCI_EXP_SLTCTL:
-               *value = PCI_EXP_SLTSTA_PDS << 16;
-               return PCI_BRIDGE_EMUL_HANDLED;
-
        /*
-        * PCI_EXP_RTCTL and PCI_EXP_RTSTA are also supported, but do not need
-        * to be handled here, because their values are stored in emulated
-        * config space buffer, and we read them from there when needed.
+        * PCI_EXP_SLTCAP, PCI_EXP_SLTCTL, PCI_EXP_RTCTL and PCI_EXP_RTSTA are
+        * also supported, but do not need to be handled here, because their
+        * values are stored in emulated config space buffer, and we read them
+        * from there when needed.
         */
 
        case PCI_EXP_LNKCAP: {
@@ -977,8 +975,25 @@ static int advk_sw_pci_bridge_init(struct advk_pcie *pcie)
        /* Support interrupt A for MSI feature */
        bridge->conf.intpin = PCI_INTERRUPT_INTA;
 
-       /* Aardvark HW provides PCIe Capability structure in version 2 */
-       bridge->pcie_conf.cap = cpu_to_le16(2);
+       /*
+        * Aardvark HW provides PCIe Capability structure in version 2 and
+        * indicate slot support, which is emulated.
+        */
+       bridge->pcie_conf.cap = cpu_to_le16(2 | PCI_EXP_FLAGS_SLOT);
+
+       /*
+        * Set Presence Detect State bit permanently since there is no support
+        * for unplugging the card nor detecting whether it is plugged. (If a
+        * platform exists in the future that supports it, via a GPIO for
+        * example, it should be implemented via this bit.)
+        *
+        * Set physical slot number to 1 since there is only one port and zero
+        * value is reserved for ports within the same silicon as Root Port
+        * which is not our case.
+        */
+       bridge->pcie_conf.slotcap = cpu_to_le32(FIELD_PREP(PCI_EXP_SLTCAP_PSN,
+                                                          1));
+       bridge->pcie_conf.slotsta = cpu_to_le16(PCI_EXP_SLTSTA_PDS);
 
        /* Indicates supports for Completion Retry Status */
        bridge->pcie_conf.rootcap = cpu_to_le16(PCI_EXP_RTCAP_CRSVIS);