pci: add CONFIG_PCI_ENUM_ONLY for platforms that don't need PCI setup done

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 <andywyse6@gmail.com>

diff --git a/README b/README
index da4341f4d6b793923d6f05eaacb9dfe8362c8b33..d45eba77d3395dc213bbd2da441a676f8d49bf32 100644 (file)
--- a/README
+++ b/README
@@ -3377,6 +3377,13 @@ 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 9a42ede56b91d31e9a3987e2a4619815c5d1f843..ae61e24907a01bdb8ac8cc227f76a00b81fe985b 100644 (file)
--- a/drivers/pci/pci_auto.c
+++ b/drivers/pci/pci_auto.c
@@ -90,12 +90,14 @@ 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;
@@ -103,20 +105,26 @@ void pciauto_setup_device(struct pci_controller *hose,
        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 {
@@ -124,26 +132,34 @@ 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);
@@ -162,9 +178,10 @@ 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");
 
@@ -357,12 +374,6 @@ 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,
@@ -429,6 +440,10 @@ int pciauto_config_device(struct pci_controller *hose, pci_dev_t dev)
                        hose->pci_prefetch, 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);