x86: pci: Allow configuration before relocation

Add simple PCI access routines for x86 which permit use before relocation.
The normal PCI stack is still used, but for pre-relocation use there can
only ever be a single hose. After relocation, fall back to the normal
access, although even then on x86 machines there is normally only a single
PCI bus.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/x86/cpu/pci.c

@@ -46,3 +46,53 @@ void pci_init_board(void)
 
 	hose->last_busno = pci_hose_scan(hose);
 }
+
+static struct pci_controller *get_hose(void)
+{
+	if (gd->arch.hose)
+		return gd->arch.hose;
+
+	return pci_bus_to_hose(0);
+}
+
+unsigned int pci_read_config8(pci_dev_t dev, unsigned where)
+{
+	uint8_t value;
+
+	pci_hose_read_config_byte(get_hose(), dev, where, &value);
+
+	return value;
+}
+
+unsigned int pci_read_config16(pci_dev_t dev, unsigned where)
+{
+	uint16_t value;
+
+	pci_hose_read_config_word(get_hose(), dev, where, &value);
+
+	return value;
+}
+
+unsigned int pci_read_config32(pci_dev_t dev, unsigned where)
+{
+	uint32_t value;
+
+	pci_hose_read_config_dword(get_hose(), dev, where, &value);
+
+	return value;
+}
+
+void pci_write_config8(pci_dev_t dev, unsigned where, unsigned value)
+{
+	pci_hose_write_config_byte(get_hose(), dev, where, value);
+}
+
+void pci_write_config16(pci_dev_t dev, unsigned where, unsigned value)
+{
+	pci_hose_write_config_word(get_hose(), dev, where, value);
+}
+
+void pci_write_config32(pci_dev_t dev, unsigned where, unsigned value)
+{
+	pci_hose_write_config_dword(get_hose(), dev, where, value);
+}

arch/x86/include/asm/pci.h

@@ -33,4 +33,17 @@ void board_pci_setup_hose(struct pci_controller *hose);
  * later use, but will become invalid one DRAM is available.
  */
 int pci_early_init_hose(struct pci_controller **hosep);
+
+/*
+ * Simple PCI access routines - these work from either the early PCI hose
+ * or the 'real' one, created after U-Boot has memory available
+ */
+unsigned int pci_read_config8(pci_dev_t dev, unsigned where);
+unsigned int pci_read_config16(pci_dev_t dev, unsigned where);
+unsigned int pci_read_config32(pci_dev_t dev, unsigned where);
+
+void pci_write_config8(pci_dev_t dev, unsigned where, unsigned value);
+void pci_write_config16(pci_dev_t dev, unsigned where, unsigned value);
+void pci_write_config32(pci_dev_t dev, unsigned where, unsigned value);
+
 #endif