/* SPDX-License-Identifier: GPL-2.0-only */ #include <device/pci.h> #include <device/pci_ops.h> #include <delay.h> void pci_s_assert_secondary_reset(pci_devfn_t p2p_bridge) { u16 reg16; reg16 = pci_s_read_config16(p2p_bridge, PCI_BRIDGE_CONTROL); reg16 |= PCI_BRIDGE_CTL_BUS_RESET; pci_s_write_config16(p2p_bridge, PCI_BRIDGE_CONTROL, reg16); } void pci_s_deassert_secondary_reset(pci_devfn_t p2p_bridge) { u16 reg16; reg16 = pci_s_read_config16(p2p_bridge, PCI_BRIDGE_CONTROL); reg16 &= ~PCI_BRIDGE_CTL_BUS_RESET; pci_s_write_config16(p2p_bridge, PCI_BRIDGE_CONTROL, reg16); } void pci_s_bridge_set_secondary(pci_devfn_t p2p_bridge, u8 secondary) { /* Disable config transaction forwarding. */ pci_s_write_config8(p2p_bridge, PCI_SECONDARY_BUS, 0x00); pci_s_write_config8(p2p_bridge, PCI_SUBORDINATE_BUS, 0x00); /* Enable config transaction forwarding. */ pci_s_write_config8(p2p_bridge, PCI_SECONDARY_BUS, secondary); pci_s_write_config8(p2p_bridge, PCI_SUBORDINATE_BUS, secondary); } static void pci_s_bridge_set_mmio(pci_devfn_t p2p_bridge, u32 base, u32 size) { u16 reg16; /* Disable MMIO window behind the bridge. */ reg16 = pci_s_read_config16(p2p_bridge, PCI_COMMAND); reg16 &= ~PCI_COMMAND_MEMORY; pci_s_write_config16(p2p_bridge, PCI_COMMAND, reg16); pci_s_write_config32(p2p_bridge, PCI_MEMORY_BASE, 0x10); if (!size) return; /* Enable MMIO window behind the bridge. */ pci_s_write_config32(p2p_bridge, PCI_MEMORY_BASE, ((base + size - 1) & 0xfff00000) | ((base >> 16) & 0xfff0)); reg16 = pci_s_read_config16(p2p_bridge, PCI_COMMAND); reg16 |= PCI_COMMAND_MEMORY; pci_s_write_config16(p2p_bridge, PCI_COMMAND, reg16); } static void pci_s_early_mmio_window(pci_devfn_t p2p_bridge, u32 mmio_base, u32 mmio_size) { int timeout, ret = -1; /* Secondary bus number is mostly irrelevant as we disable * configuration transactions right after the probe. */ u8 secondary = 15; u8 dev = 0; /* Enable configuration and MMIO over bridge. */ pci_s_assert_secondary_reset(p2p_bridge); pci_s_deassert_secondary_reset(p2p_bridge); pci_s_bridge_set_secondary(p2p_bridge, secondary); pci_s_bridge_set_mmio(p2p_bridge, mmio_base, mmio_size); for (timeout = 20000; timeout; timeout--) { pci_devfn_t dbg_dev = PCI_DEV(secondary, dev, 0); u32 id = pci_s_read_config32(dbg_dev, 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_s_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_s_bridge_set_secondary(p2p_bridge, 0); } void pci_early_bridge_init(void) { /* 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); pci_s_early_mmio_window(p2p_bridge, CONFIG_EARLY_PCI_MMIO_BASE, 0x4000); } /* FIXME: A lot of issues using the following, please avoid. * Assumes 256 PCI buses, scans them all even when PCI bridges are still * disabled. Probes all functions even if 0 is not present. */ pci_devfn_t pci_locate_device(unsigned int pci_id, pci_devfn_t dev) { for (; dev <= PCI_DEV(255, 31, 7); dev += PCI_DEV(0, 0, 1)) { unsigned int id; id = pci_s_read_config32(dev, 0); if (id == pci_id) return dev; } return PCI_DEV_INVALID; } pci_devfn_t pci_locate_device_on_bus(unsigned int pci_id, unsigned int bus) { pci_devfn_t dev, last; dev = PCI_DEV(bus, 0, 0); last = PCI_DEV(bus, 31, 7); for (; dev <= last; dev += PCI_DEV(0, 0, 1)) { unsigned int id; id = pci_s_read_config32(dev, 0); if (id == pci_id) return dev; } return PCI_DEV_INVALID; }