[U-Boot] [PATCH 1/2] drivers: pci: add map_bar support for Enhanced Allocation

[Alex Marginean <alexm.osslist@gmail.com>]

Makes dm_pci_map_bar function available for integrated PCI devices that
support Enhanced Allocation instead of original PCI BAR mechanism.

Signed-off-by: Alex Marginean <alexm.osslist@gmail.com>
---
 drivers/pci/pci-uclass.c | 47 ++++++++++++++++++++++++++++++++++++++++
 include/pci.h            |  2 +-
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
index cf1e7617ae..3204f156c3 100644
--- a/drivers/pci/pci-uclass.c
+++ b/drivers/pci/pci-uclass.c
@@ -1341,11 +1341,58 @@ pci_addr_t dm_pci_phys_to_bus(struct udevice *dev, phys_addr_t phys_addr,
 	return bus_addr;
 }
 
+static void *dm_pci_map_ea_bar(struct udevice *dev, int bar, int flags)
+{
+	int ea_off, ea_cnt, i, entry_size = 0;
+	int bar_id = bar - PCI_BASE_ADDRESS_0;
+	u32 ea_entry;
+	u64 addr;
+
+	/* handle PCI functions that use Enhanced Allocation */
+	ea_off = dm_pci_find_capability(dev, PCI_CAP_ID_EA);
+
+	if (!ea_off)
+		return 0;
+
+	/* EA capability structure header */
+	dm_pci_read_config32(dev, ea_off, &ea_entry);
+	ea_cnt = (ea_entry >> 16) & 0x3f;
+	ea_off += 4;
+
+	for (i = 0; i < ea_cnt; i++, ea_off +=  entry_size) {
+		/* Entry header */
+		dm_pci_read_config32(dev, ea_off, &ea_entry);
+		entry_size = (ea_entry & 0x7) * 4;
+
+		if (((ea_entry >> 4) & 0xf) != bar_id)
+			continue;
+
+		/* Base address, 1st DW */
+		dm_pci_read_config32(dev, ea_off + 4, &ea_entry);
+		addr = ea_entry & ~0x3;
+		if (ea_entry & 0x2) {
+			dm_pci_read_config32(dev, ea_off + 12, &ea_entry);
+			addr |= (u64)ea_entry << 32;
+		}
+
+		/* size ignored for now */
+		return map_physmem(addr, flags, 0);
+	}
+	return 0;
+}
+
 void *dm_pci_map_bar(struct udevice *dev, int bar, int flags)
 {
 	pci_addr_t pci_bus_addr;
 	u32 bar_response;
 
+	/*
+	 * if the function supports Enhanced Allocation use that instead of
+	 * BARs
+	 */
+	if (dm_pci_find_capability(dev, PCI_CAP_ID_EA))
+		return dm_pci_map_ea_bar(dev, bar, flags);
+
 	/* read BAR address */
 	dm_pci_read_config32(dev, bar, &bar_response);
 	pci_bus_addr = (pci_addr_t)(bar_response & ~0xf);
diff --git a/include/pci.h b/include/pci.h
index 508f7bca81..e1528bb257 100644
--- a/include/pci.h
+++ b/include/pci.h
@@ -1314,7 +1314,7 @@ pci_addr_t dm_pci_phys_to_bus(struct udevice *dev, phys_addr_t addr,
  * @dev:	Device to check
  * @bar:	Bar number to read (numbered from 0)
  * @flags:	Flags for the region type (PCI_REGION_...)
- * @return: pointer to the virtual address to use
+ * @return: pointer to the virtual address to use or 0 on error
  */
 void *dm_pci_map_bar(struct udevice *dev, int bar, int flags);
 
-- 
2.17.1