[PATCH v3 1/3] PCI: designware-ep: Fix find_first_zero_bit() usage

[Niklas Cassel]

find_first_zero_bit()'s parameter 'size' is defined in bits,
not in bytes.

find_first_zero_bit() was called with size in bytes rather than bits,
which thus defined a too low upper limit, causing
dw_pcie_ep_inbound_atu() to assign iatu index #4 to both bar 4
and bar 5, which made bar 5 overwrite the settings set by bar 4.

Fix this by using bitmaps with a static upper limit (MAX_IATUS).
256 was chosen since according to the databook, that is the
maximum number of iATUs supported by the IP.

Additionally, make sure that ep->num_ob_windows and ep->num_ib_windows,
which are obtained from device tree, are less than the maximum number of
iATUs (MAX_IATUS).

Fixes: f8aed6ec624f ("PCI: dwc: designware: Add EP mode support")
Signed-off-by: Niklas Cassel <niklas.cassel@xxxxxxxx>
---
 drivers/pci/dwc/pcie-designware-ep.c | 22 ++++++++++++++--------
 drivers/pci/dwc/pcie-designware.h    |  7 +++++--
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/dwc/pcie-designware-ep.c b/drivers/pci/dwc/pcie-designware-ep.c
index d53d5f168363..8b14e7db5487 100644
--- a/drivers/pci/dwc/pcie-designware-ep.c
+++ b/drivers/pci/dwc/pcie-designware-ep.c
@@ -70,8 +70,7 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, enum pci_barno bar,
 	u32 free_win;
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 
-	free_win = find_first_zero_bit(&ep->ib_window_map,
-				       sizeof(ep->ib_window_map));
+	free_win = find_first_zero_bit(ep->ib_window_map, ep->num_ib_windows);
 	if (free_win >= ep->num_ib_windows) {
 		dev_err(pci->dev, "no free inbound window\n");
 		return -EINVAL;
@@ -85,7 +84,7 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, enum pci_barno bar,
 	}
 
 	ep->bar_to_atu[bar] = free_win;
-	set_bit(free_win, &ep->ib_window_map);
+	set_bit(free_win, ep->ib_window_map);
 
 	return 0;
 }
@@ -96,8 +95,7 @@ static int dw_pcie_ep_outbound_atu(struct dw_pcie_ep *ep, phys_addr_t phys_addr,
 	u32 free_win;
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 
-	free_win = find_first_zero_bit(&ep->ob_window_map,
-				       sizeof(ep->ob_window_map));
+	free_win = find_first_zero_bit(ep->ob_window_map, ep->num_ob_windows);
 	if (free_win >= ep->num_ob_windows) {
 		dev_err(pci->dev, "no free outbound window\n");
 		return -EINVAL;
@@ -106,7 +104,7 @@ static int dw_pcie_ep_outbound_atu(struct dw_pcie_ep *ep, phys_addr_t phys_addr,
 	dw_pcie_prog_outbound_atu(pci, free_win, PCIE_ATU_TYPE_MEM,
 				  phys_addr, pci_addr, size);
 
-	set_bit(free_win, &ep->ob_window_map);
+	set_bit(free_win, ep->ob_window_map);
 	ep->outbound_addr[free_win] = phys_addr;
 
 	return 0;
@@ -121,7 +119,7 @@ static void dw_pcie_ep_clear_bar(struct pci_epc *epc, enum pci_barno bar)
 	dw_pcie_ep_reset_bar(pci, bar);
 
 	dw_pcie_disable_atu(pci, atu_index, DW_PCIE_REGION_INBOUND);
-	clear_bit(atu_index, &ep->ib_window_map);
+	clear_bit(atu_index, ep->ib_window_map);
 }
 
 static int dw_pcie_ep_set_bar(struct pci_epc *epc, enum pci_barno bar,
@@ -175,7 +173,7 @@ static void dw_pcie_ep_unmap_addr(struct pci_epc *epc, phys_addr_t addr)
 		return;
 
 	dw_pcie_disable_atu(pci, atu_index, DW_PCIE_REGION_OUTBOUND);
-	clear_bit(atu_index, &ep->ob_window_map);
+	clear_bit(atu_index, ep->ob_window_map);
 }
 
 static int dw_pcie_ep_map_addr(struct pci_epc *epc, phys_addr_t addr,
@@ -298,12 +296,20 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 		dev_err(dev, "unable to read *num-ib-windows* property\n");
 		return ret;
 	}
+	if (ep->num_ib_windows > MAX_IATUS) {
+		dev_err(dev, "invalid *num-ib-windows*\n");
+		return -EINVAL;
+	}
 
 	ret = of_property_read_u32(np, "num-ob-windows", &ep->num_ob_windows);
 	if (ret < 0) {
 		dev_err(dev, "unable to read *num-ob-windows* property\n");
 		return ret;
 	}
+	if (ep->num_ob_windows > MAX_IATUS) {
+		dev_err(dev, "invalid *num-ob-windows*\n");
+		return -EINVAL;
+	}
 
 	addr = devm_kzalloc(dev, sizeof(phys_addr_t) * ep->num_ob_windows,
 			    GFP_KERNEL);
diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie-designware.h
index e5d9d77b778e..189f45264c2a 100644
--- a/drivers/pci/dwc/pcie-designware.h
+++ b/drivers/pci/dwc/pcie-designware.h
@@ -113,6 +113,9 @@
 #define MAX_MSI_IRQS			32
 #define MAX_MSI_CTRLS			(MAX_MSI_IRQS / 32)
 
+/* Maximum number of inbound/outbound iATUs */
+#define MAX_IATUS			256
+
 struct pcie_port;
 struct dw_pcie;
 struct dw_pcie_ep;
@@ -192,8 +195,8 @@ struct dw_pcie_ep {
 	size_t			page_size;
 	u8			bar_to_atu[6];
 	phys_addr_t		*outbound_addr;
-	unsigned long		ib_window_map;
-	unsigned long		ob_window_map;
+	DECLARE_BITMAP(ib_window_map, MAX_IATUS);
+	DECLARE_BITMAP(ob_window_map, MAX_IATUS);
 	u32			num_ib_windows;
 	u32			num_ob_windows;
 };
-- 
2.14.2