[PATCH] PCI: spacemit: Ignore PERST# bit for controllers

[Ali Tariq]

The k1_pcie_init() does not set PCIE_IGNORE_PERSTN bit of the
control logic register, which causes controller to reset itself once
PERST# signal is asserted even when acting as host.
On Orange Pi RV2 (SpacemiT K1), this resets the controller and wipes
the IDs. k1_pcie_deinit() leaves PERST# asserted, so when k1_pcie_init()
runs again, its first DBI access hangs the CPU.

Set PCIE_IGNORE_PERSTN bit of the control logic register of APMU
in k1_pcie_init() before enabling resources so controllers
dont end up resetting themselves when PERST# signal is asserted.

Fixes: ff64e078e45f ("PCI: spacemit: Add SpacemiT PCIe host driver")
Signed-off-by: Ali Tariq <alitariq45892 at gmail.com>
---
Hang log: https://kernelci.cloud-v.co/scheduler/job/420
Fixed Log: https://kernelci.cloud-v.co/scheduler/job/430
---
 drivers/pci/controller/dwc/pcie-spacemit-k1.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-spacemit-k1.c b/drivers/pci/controller/dwc/pcie-spacemit-k1.c
index 92a71ea90ac3..af6028e8825a 100644
--- a/drivers/pci/controller/dwc/pcie-spacemit-k1.c
+++ b/drivers/pci/controller/dwc/pcie-spacemit-k1.c
@@ -47,6 +47,7 @@
 
 #define PCIE_CONTROL_LOGIC			0x0004
 #define PCIE_SOFT_RESET			BIT(0)
+#define PCIE_IGNORE_PERSTN		BIT(2)	/* 1: ignore PERST# */
 
 struct k1_pcie {
 	struct dw_pcie pci;
@@ -131,11 +132,19 @@ static int k1_pcie_init(struct dw_pcie_rp *pp)
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
 	struct k1_pcie *k1 = to_k1_pcie(pci);
 	u32 reset_ctrl;
+	u32 ctrl_logic;
 	u32 val;
 	int ret;
 
 	k1_pcie_toggle_soft_reset(k1);
 
+	/*
+	 * Ignore the PERST# signal so the controller does not reset
+	 * itself when it pulls PERST# low.
+	 */
+	ctrl_logic = k1->pmu_off + PCIE_CONTROL_LOGIC;
+	regmap_set_bits(k1->pmu, ctrl_logic, PCIE_IGNORE_PERSTN);
+
 	ret = k1_pcie_enable_resources(k1);
 	if (ret)
 		return ret;
-- 
2.34.1