Introduce CONFIG_PCI_ENUM_ONLY variable for platforms that just want a
quick enumberation of the PCI devices, but don't need any setup work done.
This is very beneficial on platforms that have u-boot loaded by another
boot loader which does a more sophisticated job of setup of PCI devices
than u-boot.  That way, u-boot can just read what's there and get on
with life.  This is what SeaBIOS does.

Signed-off-by: Andrew Sharp <[email protected]>
---
 README                 |    7 +++++++
 drivers/pci/pci_auto.c |   36 ++++++++++++++++++++++++++----------
 2 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/README b/README
index dac46f3..3155391 100644
--- a/README
+++ b/README
@@ -3370,6 +3370,13 @@ Low Level (hardware related) configuration options:
                Disable PCI-Express on systems where it is supported but not
                required.
 
+- CONFIG_PCI_ENUM_ONLY
+               Only scan through and get the devices on the busses.
+               Don't do any setup work, presumably because someone or
+               something has already done it, and we don't need to do it
+               a second time.  Useful for platforms that are pre-booted
+               by coreboot or similar.
+
 - CONFIG_SYS_SRIO:
                Chip has SRIO or not
 
diff --git a/drivers/pci/pci_auto.c b/drivers/pci/pci_auto.c
index dde252f..82c8855 100644
--- a/drivers/pci/pci_auto.c
+++ b/drivers/pci/pci_auto.c
@@ -90,32 +90,40 @@ void pciauto_setup_device(struct pci_controller *hose,
                          struct pci_region *io)
 {
        pci_addr_t bar_response;
-       pci_addr_t bar_value;
        pci_size_t bar_size;
        u16 cmdstat = 0;
-       struct pci_region *bar_res;
        int bar, bar_nr = 0;
+#ifndef CONFIG_PCI_ENUM_ONLY
+       pci_addr_t bar_value;
+       struct pci_region *bar_res;
        int found_mem64 = 0;
+#endif
 
        pci_hose_read_config_word(hose, dev, PCI_COMMAND, &cmdstat);
        cmdstat = (cmdstat & ~(PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) | 
PCI_COMMAND_MASTER;
 
        for (bar = PCI_BASE_ADDRESS_0; bar < PCI_BASE_ADDRESS_0 + (bars_num * 
4); bar += 4) {
                /* Tickle the BAR and get the response */
+#ifndef CONFIG_PCI_ENUM_ONLY
                pci_hose_write_config_dword(hose, dev, bar, 0xffffffff);
+#endif
                pci_hose_read_config_dword(hose, dev, bar, &bar_response);
 
                /* If BAR is not implemented go to the next BAR */
                if (!bar_response)
                        continue;
 
+#ifndef CONFIG_PCI_ENUM_ONLY
                found_mem64 = 0;
+#endif
 
                /* Check the BAR type and set our address mask */
                if (bar_response & PCI_BASE_ADDRESS_SPACE) {
                        bar_size = ((~(bar_response & PCI_BASE_ADDRESS_IO_MASK))
                                   & 0xffff) + 1;
+#ifndef CONFIG_PCI_ENUM_ONLY
                        bar_res = io;
+#endif
 
                        DEBUGF("PCI Autoconfig: BAR %d, I/O, size=0x%llx, ", 
bar_nr, (u64)bar_size);
                } else {
@@ -123,24 +131,32 @@ void pciauto_setup_device(struct pci_controller *hose,
                             PCI_BASE_ADDRESS_MEM_TYPE_64) {
                                u32 bar_response_upper;
                                u64 bar64;
+
+#ifndef CONFIG_PCI_ENUM_ONLY
                                pci_hose_write_config_dword(hose, dev, bar+4, 
0xffffffff);
+#endif
                                pci_hose_read_config_dword(hose, dev, bar+4, 
&bar_response_upper);
 
                                bar64 = ((u64)bar_response_upper << 32) | 
bar_response;
 
                                bar_size = ~(bar64 & PCI_BASE_ADDRESS_MEM_MASK) 
+ 1;
+#ifndef CONFIG_PCI_ENUM_ONLY
                                found_mem64 = 1;
+#endif
                        } else {
                                bar_size = (u32)(~(bar_response & 
PCI_BASE_ADDRESS_MEM_MASK) + 1);
                        }
+#ifndef CONFIG_PCI_ENUM_ONLY
                        if (prefetch && (bar_response & 
PCI_BASE_ADDRESS_MEM_PREFETCH))
                                bar_res = prefetch;
                        else
                                bar_res = mem;
+#endif
 
                        DEBUGF("PCI Autoconfig: BAR %d, Mem, size=0x%llx, ", 
bar_nr, (u64)bar_size);
                }
 
+#ifndef CONFIG_PCI_ENUM_ONLY
                if (pciauto_region_allocate(bar_res, bar_size, &bar_value) == 
0) {
                        /* Write it out and update our limit */
                        pci_hose_write_config_dword(hose, dev, bar, 
(u32)bar_value);
@@ -159,9 +175,11 @@ void pciauto_setup_device(struct pci_controller *hose,
 #endif
                        }
 
-                       cmdstat |= (bar_response & PCI_BASE_ADDRESS_SPACE) ?
-                               PCI_COMMAND_IO : PCI_COMMAND_MEMORY;
                }
+#endif
+
+               cmdstat |= (bar_response & PCI_BASE_ADDRESS_SPACE) ?
+                       PCI_COMMAND_IO : PCI_COMMAND_MEMORY;
 
                DEBUGF("\n");
 
@@ -352,12 +370,6 @@ int pciauto_config_device(struct pci_controller *hose, 
pci_dev_t dev)
        pci_hose_read_config_word(hose, dev, PCI_CLASS_DEVICE, &class);
 
        switch (class) {
-       case PCI_CLASS_PROCESSOR_POWERPC: /* an agent or end-point */
-               DEBUGF("PCI AutoConfig: Found PowerPC device\n");
-               pciauto_setup_device(hose, dev, 6, hose->pci_mem,
-                                    hose->pci_prefetch, hose->pci_io);
-               break;
-
        case PCI_CLASS_BRIDGE_PCI:
                hose->current_busno++;
                pciauto_setup_device(hose, dev, 2, hose->pci_mem, 
hose->pci_prefetch,
@@ -423,6 +435,10 @@ int pciauto_config_device(struct pci_controller *hose, 
pci_dev_t dev)
                                hose->pci_io);
                break;
 #endif
+
+       case PCI_CLASS_PROCESSOR_POWERPC: /* an agent or end-point */
+               DEBUGF("PCI AutoConfig: Found PowerPC device\n");
+
        default:
                pciauto_setup_device(hose, dev, 6, hose->pci_mem, 
hose->pci_prefetch,
                                hose->pci_io);
-- 
1.7.1

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