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/* SPDX-License-Identifier: GPL-2.0-only */
/* This file is part of the coreboot project. */
#include <device/pci.h>
#include <device/pci_def.h>
#include <device/pci_ops.h>
#include <device/pci_type.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 busses, 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;
}
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