[PATCH v2 2/2] PCI: dwc: rcar-gen4: Use .post_deinit to handle dw_pcie_ep_init() failures

[Marek Vasut]

Implement .post_deinit() callback in R-Car Gen4 struct dw_pcie_ep_ops {}
which asserts reset and stops the clock. This undoes start of clock and
deassert of reset performed in .pre_init() in case dw_pcie_ep_init() fails
after successful call of .pre_init() callback.

The use of .post_deinit() callback correctly handles the clock and reset
stop, unlike the call of rcar_gen4_pcie_ep_deinit() in dw_pcie_ep_init()
which could not discern at which point the dw_pcie_ep_init() failed and
might have attempted to stop clock and assert reset twice, remove it.

Since dw_pcie_ep_deinit() also invokes the .post_deinit() callback, drop
calls to rcar_gen4_pcie_ep_deinit() in both rcar_gen4_add_dw_pcie_ep()
dw_pcie_ep_init_registers() fail path and rcar_gen4_remove_dw_pcie_ep()
to avoid duplicate stop of clock and assert of reset, and drop no longer
used rcar_gen4_pcie_ep_deinit() entirely.

Initialize PCIEDMAINTSTSEN early in rcar_gen4_pcie_ep_pre_init() to 0,
to make sure that edma_int bits will never be set in case of failure
of dw_pcie_ep_init(), and will only be set in case dw_pcie_ep_init()
succeeds.

Signed-off-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxxxx>
---
Cc: "Krzysztof Wilczyński" <kwilczynski@xxxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Cc: Koichiro Den <den@xxxxxxxxxxxxx>
Cc: Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx>
Cc: Magnus Damm <magnus.damm@xxxxxxxxx>
Cc: Manivannan Sadhasivam <mani@xxxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-pci@xxxxxxxxxxxxxxx
Cc: linux-renesas-soc@xxxxxxxxxxxxxxx
---
V2: This is reworked version of
    PCI: dwc: rcar-gen4: Fix potential unclocked access in rcar_gen4_pcie_ep_deinit()
---
 drivers/pci/controller/dwc/pcie-rcar-gen4.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
index fbe465a29068f..157e33c4089b9 100644
--- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
+++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
@@ -487,6 +487,8 @@ static int rcar_gen4_pcie_ep_pre_init(struct dw_pcie_ep *ep)
 	struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
 	int ret;
 
+	writel(0, rcar->base + PCIEDMAINTSTSEN);
+
 	ret = rcar_gen4_pcie_common_init(rcar);
 	if (ret)
 		return ret;
@@ -496,8 +498,11 @@ static int rcar_gen4_pcie_ep_pre_init(struct dw_pcie_ep *ep)
 	return 0;
 }
 
-static void rcar_gen4_pcie_ep_deinit(struct rcar_gen4_pcie *rcar)
+static void rcar_gen4_pcie_ep_post_deinit(struct dw_pcie_ep *ep)
 {
+	struct dw_pcie *dw = to_dw_pcie_from_ep(ep);
+	struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
+
 	writel(0, rcar->base + PCIEDMAINTSTSEN);
 	rcar_gen4_pcie_common_deinit(rcar);
 }
@@ -552,6 +557,7 @@ static unsigned int rcar_gen4_pcie_ep_get_dbi2_offset(struct dw_pcie_ep *ep,
 
 static const struct dw_pcie_ep_ops pcie_ep_ops = {
 	.pre_init = rcar_gen4_pcie_ep_pre_init,
+	.post_deinit = rcar_gen4_pcie_ep_post_deinit,
 	.raise_irq = rcar_gen4_pcie_ep_raise_irq,
 	.get_features = rcar_gen4_pcie_ep_get_features,
 	.get_dbi_offset = rcar_gen4_pcie_ep_get_dbi_offset,
@@ -570,16 +576,13 @@ static int rcar_gen4_add_dw_pcie_ep(struct rcar_gen4_pcie *rcar)
 	ep->ops = &pcie_ep_ops;
 
 	ret = dw_pcie_ep_init(ep);
-	if (ret) {
-		rcar_gen4_pcie_ep_deinit(rcar);
+	if (ret)
 		return ret;
-	}
 
 	ret = dw_pcie_ep_init_registers(ep);
 	if (ret) {
 		dev_err(dev, "Failed to initialize DWC endpoint registers\n");
 		dw_pcie_ep_deinit(ep);
-		rcar_gen4_pcie_ep_deinit(rcar);
 	}
 
 	pci_epc_init_notify(ep->epc);
@@ -590,7 +593,6 @@ static int rcar_gen4_add_dw_pcie_ep(struct rcar_gen4_pcie *rcar)
 static void rcar_gen4_remove_dw_pcie_ep(struct rcar_gen4_pcie *rcar)
 {
 	dw_pcie_ep_deinit(&rcar->dw.ep);
-	rcar_gen4_pcie_ep_deinit(rcar);
 }
 
 /* Common */
-- 
2.53.0