commit f83567e0c08e87e4aaeef80ce9ca45986977c451
author Vladimir Oltean <vladimir.oltean@nxp.com> Fri Mar 13 16:53:06 2020 +0200
committer Priyanka Jain <priyanka.jain@nxp.com> Mon Mar 30 08:11:56 2020 +0530
tree c147c7e9e9a2391f059fdead24fc68f6cb48c341
parent 095b6be41ecf1cfef24d762ab9fdc062367ffeda

pci-host-ecam-generic: access config space independent of system-wide bus id

The pci-host-ecam-generic code assumes that the ECAM is the first PCI
bus in the system to be probed. Therefore, the system-wide bus number
allocated by U-Boot in sequence for it is going to be zero, which
corresponds to the memory-mapped config spaces found within it.

Reuse the logic from other PCI bus drivers, and assume that U-Boot will
allocate bus numbers in sequence for all buses within the current ECAM.
So the base number of the bus needs to be subtracted when indexing the
correct config space.

Fixes: 3675cb044e68 ("PCI: Add driver for a 'pci-host-ecam-generic' host controller")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Alex Marginean <alexandru.marginean@nxp.com>
Signed-off-by: Priyanka Jain <priyanka.jain@nxp.com>

drivers/pci/pcie_ecam_generic.c

diff --git a/drivers/pci/pcie_ecam_generic.c b/drivers/pci/pcie_ecam_generic.c
index c875f3a..890b6a8 100644
--- a/drivers/pci/pcie_ecam_generic.c
+++ b/drivers/pci/pcie_ecam_generic.c
@@ -19,6 +19,8 @@
  */
 struct generic_ecam_pcie {
 	void *cfg_base;
+	pci_size_t size;
+	int first_busno;
 };
 
 /**
@@ -43,7 +45,7 @@
 	void *addr;
 
 	addr = pcie->cfg_base;
-	addr += PCI_BUS(bdf) << 20;
+	addr += (PCI_BUS(bdf) - pcie->first_busno) << 20;
 	addr += PCI_DEV(bdf) << 15;
 	addr += PCI_FUNC(bdf) << 12;
 	addr += offset;
@@ -52,6 +54,16 @@
 	return 0;
 }
 
+static bool pci_generic_ecam_addr_valid(const struct udevice *bus,
+					pci_dev_t bdf)
+{
+	struct generic_ecam_pcie *pcie = dev_get_priv(bus);
+	int num_buses = DIV_ROUND_UP(pcie->size, 1 << 16);
+
+	return (PCI_BUS(bdf) >= pcie->first_busno &&
+		PCI_BUS(bdf) < pcie->first_busno + num_buses);
+}
+
 /**
  * pci_generic_ecam_read_config() - Read from configuration space
  * @bus: Pointer to the PCI bus
@@ -68,6 +80,11 @@
 					pci_dev_t bdf, uint offset,
 					ulong *valuep, enum pci_size_t size)
 {
+	if (!pci_generic_ecam_addr_valid(bus, bdf)) {
+		*valuep = pci_get_ff(size);
+		return 0;
+	}
+
 	return pci_generic_mmap_read_config(bus, pci_generic_ecam_conf_address,
 					    bdf, offset, valuep, size);
 }
@@ -88,6 +105,9 @@
 				    uint offset, ulong value,
 				    enum pci_size_t size)
 {
+	if (!pci_generic_ecam_addr_valid(bus, bdf))
+		return 0;
+
 	return pci_generic_mmap_write_config(bus, pci_generic_ecam_conf_address,
 					     bdf, offset, value, size);
 }
@@ -116,9 +136,17 @@
 		return err;
 	}
 
-	pcie->cfg_base = map_physmem(reg_res.start,
-				     fdt_resource_size(&reg_res),
-				     MAP_NOCACHE);
+	pcie->size = fdt_resource_size(&reg_res);
+	pcie->cfg_base = map_physmem(reg_res.start, pcie->size, MAP_NOCACHE);
+
+	return 0;
+}
+
+static int pci_generic_ecam_probe(struct udevice *dev)
+{
+	struct generic_ecam_pcie *pcie = dev_get_priv(dev);
+
+	pcie->first_busno = dev->seq;
 
 	return 0;
 }
@@ -138,6 +166,7 @@
 	.id			= UCLASS_PCI,
 	.of_match		= pci_generic_ecam_ids,
 	.ops			= &pci_generic_ecam_ops,
+	.probe			= pci_generic_ecam_probe,
 	.ofdata_to_platdata	= pci_generic_ecam_ofdata_to_platdata,
 	.priv_auto_alloc_size	= sizeof(struct generic_ecam_pcie),
 };