diff options
Diffstat (limited to 'src/device/pci_early.c')
| -rw-r--r-- | src/device/pci_early.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/src/device/pci_early.c b/src/device/pci_early.c index c15a4d0f77..e31287e8bf 100644 --- a/src/device/pci_early.c +++ b/src/device/pci_early.c @@ -1,6 +1,8 @@ /* * This file is part of the coreboot project. * + * Copyright (C) 2011 Google Inc + * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2 of the License. @@ -15,9 +17,14 @@ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA, 02110-1301 USA */ +#define __SIMPLE_DEVICE__ + #include <arch/io.h> #include <device/pci.h> #include <device/pci_def.h> +#include <delay.h> + +#ifdef __PRE_RAM__ unsigned pci_find_next_capability(device_t dev, unsigned cap, unsigned last) { @@ -66,3 +73,100 @@ unsigned pci_find_capability(device_t dev, unsigned cap) { return pci_find_next_capability(dev, cap, 0); } +#endif + + +#if CONFIG_EARLY_PCI_BRIDGE + +static void pci_bridge_reset_secondary(device_t p2p_bridge) +{ + u16 reg16; + + /* First we reset the secondary bus. */ + reg16 = pci_read_config16(p2p_bridge, PCI_BRIDGE_CONTROL); + reg16 |= (1 << 6); /* SRESET */ + pci_write_config16(p2p_bridge, PCI_BRIDGE_CONTROL, reg16); + + /* Assume we don't have to wait here forever */ + + /* Read back and clear reset bit. */ + reg16 = pci_read_config16(p2p_bridge, PCI_BRIDGE_CONTROL); + reg16 &= ~(1 << 6); /* SRESET */ + pci_write_config16(p2p_bridge, PCI_BRIDGE_CONTROL, reg16); +} + +static void pci_bridge_set_secondary(device_t p2p_bridge, u8 secondary) +{ + /* Disable config transaction forwarding. */ + pci_write_config8(p2p_bridge, PCI_SECONDARY_BUS, 0x00); + pci_write_config8(p2p_bridge, PCI_SUBORDINATE_BUS, 0x00); + /* Enable config transaction forwarding. */ + pci_write_config8(p2p_bridge, PCI_SECONDARY_BUS, secondary); + pci_write_config8(p2p_bridge, PCI_SUBORDINATE_BUS, secondary); +} + +static void pci_bridge_set_mmio(device_t p2p_bridge, u32 base, u32 size) +{ + u16 reg16; + + /* Disable MMIO window behind the bridge. */ + reg16 = pci_read_config16(p2p_bridge, PCI_COMMAND); + reg16 &= ~PCI_COMMAND_MEMORY; + pci_write_config16(p2p_bridge, PCI_COMMAND, reg16); + pci_write_config32(p2p_bridge, PCI_MEMORY_BASE, 0x10); + + if (!size) + return; + + /* Enable MMIO window behind the bridge. */ + pci_write_config32(p2p_bridge, PCI_MEMORY_BASE, + ((base + size - 1) & 0xfff00000) | ((base >> 16) & 0xfff0)); + + reg16 = pci_read_config16(p2p_bridge, PCI_COMMAND); + reg16 |= PCI_COMMAND_MEMORY; + pci_write_config16(p2p_bridge, PCI_COMMAND, reg16); +} + +void pci_early_bridge_init(void) +{ + int timeout, ret = -1; + + /* No PCI-to-PCI bridges are enabled yet, so the one we try to + * configure must have its primary on bus 0. + */ + pci_devfn_t p2p_bridge = PCI_DEV(0, CONFIG_EARLY_PCI_BRIDGE_DEVICE, + CONFIG_EARLY_PCI_BRIDGE_FUNCTION); + + /* Secondary bus number is mostly irrelevant as we disable + * configuration transactions right after the probe. + */ + u8 secondary = 15; + u8 dev = 0; + u32 mmio_base = CONFIG_EARLY_PCI_MMIO_BASE; + + /* Enable configuration and MMIO over bridge. */ + pci_bridge_reset_secondary(p2p_bridge); + pci_bridge_set_secondary(p2p_bridge, secondary); + pci_bridge_set_mmio(p2p_bridge, mmio_base, 0x4000); + + for (timeout = 20000; timeout; timeout--) { + u32 id = pci_read_config32(PCI_DEV(secondary, dev, 0), PCI_VENDOR_ID); + if (id != 0 && id != 0xffffffff && id != 0xffff0001) + break; + udelay(10); + } + + if (timeout != 0) + ret = pci_early_device_probe(secondary, dev, mmio_base); + + /* Disable MMIO window if we found no suitable device. */ + if (ret) + pci_bridge_set_mmio(p2p_bridge, 0, 0); + + /* Resource allocator will reconfigure bridges and secondary bus + * number may change. Thus early device cannot reliably use config + * transactions from here on, so we may as well disable them. + */ + pci_bridge_set_secondary(p2p_bridge, 0); +} +#endif /* CONFIG_EARLY_PCI_BRIDGE */ |