[PATCH 1/1] PCI: dwc: Fix BAR0 wrong map to iATU6 after root complex reinit endpoint

[Frank Li]

dw_pcie_ep_inbound_atu()
{
	...
	if (!ep->bar_to_atu[bar])
		free_win = find_first_zero_bit(ep->ib_window_map, pci->num_ib_windows);
	else
		free_win = ep->bar_to_atu[bar];
	...
}

The atu index 0 is valid case for atu number. The find_first_zero_bit()
will return 6 when second time call into this function if atu is 0. Suppose
it should use branch 'free_win = ep->bar_to_atu[bar]'.

Change 'bar_to_atu' to s8. Initialize bar_to_atu as -1 to indicate it have
not allocate atu to the bar.

Reported-by: Niklas Cassel <Niklas.Cassel@xxxxxxx>
Close: https://lore.kernel.org/linux-pci/ZXt2A+Fusfz3luQV@x1-carbon/T/#u
Fixes: 4284c88fff0e ("PCI: designware-ep: Allow pci_epc_set_bar() update inbound map address")
Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---

Notes:
    @Niklas:
    	I have not test your case. I should be equal to previous's fix in
    mail list.

 drivers/pci/controller/dwc/pcie-designware-ep.c | 11 ++++++++---
 drivers/pci/controller/dwc/pcie-designware.h    |  2 +-
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index f6207989fc6ad..0ff5cd64f49b0 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -174,7 +174,7 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, u8 func_no, int type,
 	u32 free_win;
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 
-	if (!ep->bar_to_atu[bar])
+	if (ep->bar_to_atu[bar] < 0)
 		free_win = find_first_zero_bit(ep->ib_window_map, pci->num_ib_windows);
 	else
 		free_win = ep->bar_to_atu[bar];
@@ -228,14 +228,17 @@ static void dw_pcie_ep_clear_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 	struct dw_pcie_ep *ep = epc_get_drvdata(epc);
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 	enum pci_barno bar = epf_bar->barno;
-	u32 atu_index = ep->bar_to_atu[bar];
+	s8 atu_index = ep->bar_to_atu[bar];
+
+	if (atu_index < 0)
+		return;
 
 	__dw_pcie_ep_reset_bar(pci, func_no, bar, epf_bar->flags);
 
 	dw_pcie_disable_atu(pci, PCIE_ATU_REGION_DIR_IB, atu_index);
 	clear_bit(atu_index, ep->ib_window_map);
 	ep->epf_bar[bar] = NULL;
-	ep->bar_to_atu[bar] = 0;
+	ep->bar_to_atu[bar] = -1;
 }
 
 static int dw_pcie_ep_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
@@ -767,6 +770,8 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 		return -ENOMEM;
 	ep->outbound_addr = addr;
 
+	memset(ep->bar_to_atu, -1, sizeof(ep->bar_to_atu));
+
 	epc = devm_pci_epc_create(dev, &epc_ops);
 	if (IS_ERR(epc)) {
 		dev_err(dev, "Failed to create epc device\n");
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 55ff76e3d3846..5879907c5cf25 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -362,7 +362,7 @@ struct dw_pcie_ep {
 	phys_addr_t		phys_base;
 	size_t			addr_size;
 	size_t			page_size;
-	u8			bar_to_atu[PCI_STD_NUM_BARS];
+	s8			bar_to_atu[PCI_STD_NUM_BARS];
 	phys_addr_t		*outbound_addr;
 	unsigned long		*ib_window_map;
 	unsigned long		*ob_window_map;
-- 
2.34.1