[PATCH AUTOSEL 5.19 12/64] PCI: aardvark: Fix reporting Slot capabilities on emulated bridge

Sasha Levin
2022-08-14T15:27:51Z

From: Pali Rohár <pali@kernel.org>

[ 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>
---
drivers/pci/controller/pci-aardvark.c | 33 +++++++++++++++++++--------
1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index ffec82c8a523..62db476a8651 100644
--- 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);
--
2.35.1