drivers: pci: add map_bar support for Enhanced Allocation

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

Signed-off-by: Alex Marginean <alexm.osslist@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

1 files changed, 46 insertions, 0 deletions

diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
index cf1e7617ae..389aec15ce 100644
--- a/drivers/pci/pci-uclass.c
+++ b/drivers/pci/pci-uclass.c
@@ -1341,10 +1341,56 @@ 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)
+{
+	int ea_cnt, i, entry_size;
+	int bar_id = (bar - PCI_BASE_ADDRESS_0) >> 2;
+	u32 ea_entry;
+	phys_addr_t addr;
+
+	/* EA capability structure header */
+	dm_pci_read_config32(dev, ea_off, &ea_entry);
+	ea_cnt = (ea_entry >> 16) & PCI_EA_NUM_ENT_MASK;
+	ea_off += PCI_EA_FIRST_ENT;
+
+	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 & PCI_EA_ES) + 1) << 2;
+
+		if (((ea_entry & PCI_EA_BEI) >> 4) != bar_id)
+			continue;
+
+		/* Base address, 1st DW */
+		dm_pci_read_config32(dev, ea_off + 4, &ea_entry);
+		addr = ea_entry & PCI_EA_FIELD_MASK;
+		if (ea_entry & PCI_EA_IS_64) {
+			/* Base address, 2nd DW, skip over 4B MaxOffset */
+			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;
+	int ea_off;
+
+	/*
+	 * if the function supports Enhanced Allocation use that instead of
+	 * BARs
+	 */
+	ea_off = dm_pci_find_capability(dev, PCI_CAP_ID_EA);
+	if (ea_off)
+		return dm_pci_map_ea_bar(dev, bar, flags, ea_off);
 
 	/* read BAR address */
 	dm_pci_read_config32(dev, bar, &bar_response);