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154 lines
3.2 KiB
154 lines
3.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* mmconfig.c - Low-level direct PCI config space access via MMCONFIG |
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* |
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* This is an 64bit optimized version that always keeps the full mmconfig |
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* space mapped. This allows lockless config space operation. |
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*/ |
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#include <linux/pci.h> |
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#include <linux/init.h> |
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#include <linux/acpi.h> |
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#include <linux/bitmap.h> |
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#include <linux/rcupdate.h> |
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#include <asm/e820/api.h> |
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#include <asm/pci_x86.h> |
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#define PREFIX "PCI: " |
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static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn) |
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{ |
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struct pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus); |
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if (cfg && cfg->virt) |
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return cfg->virt + (PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12)); |
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return NULL; |
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} |
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static int pci_mmcfg_read(unsigned int seg, unsigned int bus, |
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unsigned int devfn, int reg, int len, u32 *value) |
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{ |
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char __iomem *addr; |
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/* Why do we have this when nobody checks it. How about a BUG()!? -AK */ |
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if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) { |
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err: *value = -1; |
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return -EINVAL; |
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} |
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rcu_read_lock(); |
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addr = pci_dev_base(seg, bus, devfn); |
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if (!addr) { |
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rcu_read_unlock(); |
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goto err; |
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} |
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switch (len) { |
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case 1: |
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*value = mmio_config_readb(addr + reg); |
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break; |
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case 2: |
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*value = mmio_config_readw(addr + reg); |
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break; |
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case 4: |
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*value = mmio_config_readl(addr + reg); |
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break; |
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} |
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rcu_read_unlock(); |
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return 0; |
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} |
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static int pci_mmcfg_write(unsigned int seg, unsigned int bus, |
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unsigned int devfn, int reg, int len, u32 value) |
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{ |
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char __iomem *addr; |
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/* Why do we have this when nobody checks it. How about a BUG()!? -AK */ |
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if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) |
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return -EINVAL; |
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rcu_read_lock(); |
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addr = pci_dev_base(seg, bus, devfn); |
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if (!addr) { |
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rcu_read_unlock(); |
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return -EINVAL; |
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} |
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switch (len) { |
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case 1: |
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mmio_config_writeb(addr + reg, value); |
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break; |
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case 2: |
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mmio_config_writew(addr + reg, value); |
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break; |
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case 4: |
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mmio_config_writel(addr + reg, value); |
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break; |
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} |
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rcu_read_unlock(); |
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return 0; |
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} |
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const struct pci_raw_ops pci_mmcfg = { |
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.read = pci_mmcfg_read, |
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.write = pci_mmcfg_write, |
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}; |
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static void __iomem *mcfg_ioremap(struct pci_mmcfg_region *cfg) |
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{ |
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void __iomem *addr; |
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u64 start, size; |
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int num_buses; |
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start = cfg->address + PCI_MMCFG_BUS_OFFSET(cfg->start_bus); |
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num_buses = cfg->end_bus - cfg->start_bus + 1; |
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size = PCI_MMCFG_BUS_OFFSET(num_buses); |
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addr = ioremap(start, size); |
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if (addr) |
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addr -= PCI_MMCFG_BUS_OFFSET(cfg->start_bus); |
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return addr; |
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} |
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int __init pci_mmcfg_arch_init(void) |
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{ |
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struct pci_mmcfg_region *cfg; |
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list_for_each_entry(cfg, &pci_mmcfg_list, list) |
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if (pci_mmcfg_arch_map(cfg)) { |
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pci_mmcfg_arch_free(); |
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return 0; |
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} |
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raw_pci_ext_ops = &pci_mmcfg; |
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return 1; |
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} |
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void __init pci_mmcfg_arch_free(void) |
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{ |
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struct pci_mmcfg_region *cfg; |
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list_for_each_entry(cfg, &pci_mmcfg_list, list) |
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pci_mmcfg_arch_unmap(cfg); |
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} |
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int pci_mmcfg_arch_map(struct pci_mmcfg_region *cfg) |
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{ |
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cfg->virt = mcfg_ioremap(cfg); |
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if (!cfg->virt) { |
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pr_err(PREFIX "can't map MMCONFIG at %pR\n", &cfg->res); |
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return -ENOMEM; |
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} |
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return 0; |
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} |
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void pci_mmcfg_arch_unmap(struct pci_mmcfg_region *cfg) |
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{ |
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if (cfg && cfg->virt) { |
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iounmap(cfg->virt + PCI_MMCFG_BUS_OFFSET(cfg->start_bus)); |
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cfg->virt = NULL; |
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} |
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}
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