mb/pcengines/apu2: add reset logic for PCIe slots

PC Engines apu2 had many problems with PCIe cards detection. The cards
were inconsistently detected when booted from G3, S5 or after a reboot.
AGESA can reset PCIe slots using GPIO via callback. Use it to reset the
slots that support using GPIO as reset signal.

Signed-off-by: Michał Żygowski <michal.zygowski@3mdeb.com>
Change-Id: I8ff7db6ff85cce45b84729be905e6c895a24f6f2
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39703
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

3 files changed, 94 insertions, 5 deletions

diff --git a/src/mainboard/pcengines/apu2/BiosCallOuts.c b/src/mainboard/pcengines/apu2/BiosCallOuts.c
index d6f8d84300..69af3f9db3 100644
--- a/src/mainboard/pcengines/apu2/BiosCallOuts.c
+++ b/src/mainboard/pcengines/apu2/BiosCallOuts.c
@@ -13,6 +13,7 @@
  */
 
 #include <AGESA.h>
+#include <amdblocks/acpimmio.h>
 #include <console/console.h>
 #include <spd_bin.h>
 #include <northbridge/amd/agesa/BiosCallOuts.h>
@@ -24,6 +25,7 @@
 #include "hudson.h"
 
 static AGESA_STATUS board_ReadSpd_from_cbfs(UINT32 Func, UINTN Data, VOID *ConfigPtr);
+static AGESA_STATUS board_GnbPciExSlotReset(UINT32 Func, UINTN Data, VOID *ConfigPtr);
 
 const BIOS_CALLOUT_STRUCT BiosCallouts[] =
 {
@@ -32,6 +34,7 @@ const BIOS_CALLOUT_STRUCT BiosCallouts[] =
 	{AGESA_READ_SPD_RECOVERY,        agesa_NoopUnsupported },
 	{AGESA_RUNFUNC_ONAP,             agesa_RunFuncOnAp },
 	{AGESA_GET_IDS_INIT_DATA,        agesa_EmptyIdsInitData },
+	{AGESA_GNB_PCIE_SLOT_RESET,      board_GnbPciExSlotReset },
 	{AGESA_HOOKBEFORE_DQS_TRAINING,  agesa_NoopSuccess },
 	{AGESA_HOOKBEFORE_EXIT_SELF_REF, agesa_NoopSuccess }
 };
@@ -139,3 +142,71 @@ static AGESA_STATUS board_ReadSpd_from_cbfs(UINT32 Func, UINTN Data, VOID *Confi
 
 	return AGESA_SUCCESS;
 }
+
+/* PCIE slot reset control */
+static AGESA_STATUS board_GnbPciExSlotReset(UINT32 Func, UINTN Data, VOID *ConfigPtr)
+{
+	AGESA_STATUS		Status;
+	PCIe_SLOT_RESET_INFO	*ResetInfo;
+	uint32_t		GpioData;
+	uint8_t			GpioValue;
+
+	ResetInfo = ConfigPtr;
+	Status = AGESA_UNSUPPORTED;
+
+	switch (ResetInfo->ResetId) {
+	/*
+	 * ResetID 1 = PCIE_RST# affects all PCIe slots on all boards except
+	 * apu2. ResetID 1 does not need any GPIO.
+	 */
+	case 1:
+		Status = AGESA_SUCCESS;
+		break;
+	case 51: /* GPIO51 resets mPCIe1 slot on apu2 */
+		switch (ResetInfo->ResetControl) {
+		case AssertSlotReset:
+			GpioData = gpio1_read32(0x8);
+			printk(BIOS_DEBUG, "%s: ResetID %u assert %08x\n",
+				__func__, ResetInfo->ResetId, GpioData);
+			GpioValue = gpio1_read8(0xa);
+			GpioValue &= ~BIT6;
+			gpio1_write8(0xa, GpioValue);
+			Status = AGESA_SUCCESS;
+			break;
+		case DeassertSlotReset:
+			GpioData = gpio1_read32(0x8);
+			printk(BIOS_DEBUG, "%s: ResetID %u deassert %08x\n",
+				__func__, ResetInfo->ResetId, GpioData);
+			GpioValue = gpio1_read8(0xa);
+			GpioValue |= BIT6;
+			gpio1_write8(0xa, GpioValue);
+			Status = AGESA_SUCCESS;
+			break;
+		}
+		break;
+	case 55: /* GPIO51 resets mPCIe2 slot on apu2 */
+		switch (ResetInfo->ResetControl) {
+		case AssertSlotReset:
+			GpioData = gpio1_read32(0xc);
+			printk(BIOS_DEBUG, "%s: ResetID %u assert %08x\n",
+				__func__, ResetInfo->ResetId, GpioData);
+			GpioValue = gpio1_read8(0xe);
+			GpioValue &= ~BIT6;
+			gpio1_write8(0xa, GpioValue);
+			Status = AGESA_SUCCESS;
+			break;
+		case DeassertSlotReset:
+			GpioData = gpio1_read32(0xc);
+			printk(BIOS_DEBUG, "%s: ResetID %u deassert %08x\n",
+				__func__, ResetInfo->ResetId, GpioData);
+			GpioValue = gpio1_read8(0xe);
+			GpioValue |= BIT6;
+			gpio1_write8(0xa, GpioValue);
+			Status = AGESA_SUCCESS;
+			break;
+		}
+		break;
+	}
+
+	return Status;
+}
diff --git a/src/mainboard/pcengines/apu2/OemCustomize.c b/src/mainboard/pcengines/apu2/OemCustomize.c
index 99b9d518e7..6339e0fc4a 100644
--- a/src/mainboard/pcengines/apu2/OemCustomize.c
+++ b/src/mainboard/pcengines/apu2/OemCustomize.c
@@ -15,6 +15,15 @@
 #include <AGESA.h>
 #include <northbridge/amd/agesa/state_machine.h>
 
+#define PCIE_NIC_RESET_ID	1
+
+#if CONFIG(BOARD_PCENGINES_APU2)
+#define	PCIE_GFX_RESET_ID	55
+#define PCIE_PORT3_RESET_ID	51
+#else
+#define	PCIE_GFX_RESET_ID	PCIE_NIC_RESET_ID
+#define PCIE_PORT3_RESET_ID	PCIE_NIC_RESET_ID
+#endif
 
 static const PCIe_PORT_DESCRIPTOR PortList[] = {
 	{
@@ -24,7 +33,7 @@ static const PCIe_PORT_DESCRIPTOR PortList[] = {
 				HotplugDisabled,
 				PcieGenMaxSupported,
 				PcieGenMaxSupported,
-				AspmDisabled, 0x01, 0)
+				AspmDisabled, PCIE_PORT3_RESET_ID, 0)
 	},
 	/* Initialize Port descriptor (PCIe port, Lanes 1, PCI Device Number 2, ...) */
 	{
@@ -34,7 +43,7 @@ static const PCIe_PORT_DESCRIPTOR PortList[] = {
 				HotplugDisabled,
 				PcieGenMaxSupported,
 				PcieGenMaxSupported,
-				AspmDisabled, 0x02, 0)
+				AspmDisabled, PCIE_NIC_RESET_ID, 0)
 	},
 	/* Initialize Port descriptor (PCIe port, Lanes 2, PCI Device Number 2, ...) */
 	{
@@ -44,7 +53,7 @@ static const PCIe_PORT_DESCRIPTOR PortList[] = {
 				HotplugDisabled,
 				PcieGenMaxSupported,
 				PcieGenMaxSupported,
-				AspmDisabled, 0x03, 0)
+				AspmDisabled, PCIE_NIC_RESET_ID, 0)
 	},
 	/* Initialize Port descriptor (PCIe port, Lanes 3, PCI Device Number 2, ...) */
 	{
@@ -54,7 +63,7 @@ static const PCIe_PORT_DESCRIPTOR PortList[] = {
 				HotplugDisabled,
 				PcieGenMaxSupported,
 				PcieGenMaxSupported,
-				AspmDisabled, 0x04, 0)
+				AspmDisabled, PCIE_NIC_RESET_ID, 0)
 	},
 	/* Initialize Port descriptor (PCIe port, Lanes 4-7, PCI Device Number 4, ...) */
 	{
@@ -64,7 +73,7 @@ static const PCIe_PORT_DESCRIPTOR PortList[] = {
 				HotplugDisabled,
 				PcieGenMaxSupported,
 				PcieGenMaxSupported,
-				AspmDisabled, 0x05, 0)
+				AspmDisabled, PCIE_GFX_RESET_ID, 0)
 	}
 };
 
diff --git a/src/mainboard/pcengines/apu2/romstage.c b/src/mainboard/pcengines/apu2/romstage.c
index 7565bfca1d..34c42b43ff 100644
--- a/src/mainboard/pcengines/apu2/romstage.c
+++ b/src/mainboard/pcengines/apu2/romstage.c
@@ -38,6 +38,15 @@ void board_BeforeAgesa(struct sysinfo *cb)
 
 	/* Release GPIO32/33 for other uses. */
 	pm_write8(0xea, 1);
+
+	/*
+	 * Assert resets on the PCIe slots, since AGESA calls deassert callout
+	 * only. Only apu2 uses GPIOs to reset PCIe slots.
+	 */
+	if (CONFIG(BOARD_PCENGINES_APU2)) {
+		gpio1_write8(0xa, gpio1_read8(0xa) & ~(1 << 6));
+		gpio1_write8(0xe, gpio1_read8(0xe) & ~(1 << 6));
+	}
 }
 
 static void early_lpc_init(void)