diff options
Diffstat (limited to 'arch/x86/pci/mmconfig_64.c')
| -rw-r--r-- | arch/x86/pci/mmconfig_64.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/arch/x86/pci/mmconfig_64.c b/arch/x86/pci/mmconfig_64.c new file mode 100644 index 000000000..887d181b7 --- /dev/null +++ b/arch/x86/pci/mmconfig_64.c @@ -0,0 +1,154 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * mmconfig.c - Low-level direct PCI config space access via MMCONFIG + * + * This is an 64bit optimized version that always keeps the full mmconfig + * space mapped. This allows lockless config space operation. + */ + +#include <linux/pci.h> +#include <linux/init.h> +#include <linux/acpi.h> +#include <linux/bitmap.h> +#include <linux/rcupdate.h> +#include <asm/e820/api.h> +#include <asm/pci_x86.h> + +#define PREFIX "PCI: " + +static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn) +{ + struct pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus); + + if (cfg && cfg->virt) + return cfg->virt + (PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12)); + return NULL; +} + +static int pci_mmcfg_read(unsigned int seg, unsigned int bus, + unsigned int devfn, int reg, int len, u32 *value) +{ + char __iomem *addr; + + /* Why do we have this when nobody checks it. How about a BUG()!? -AK */ + if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) { +err: *value = -1; + return -EINVAL; + } + + rcu_read_lock(); + addr = pci_dev_base(seg, bus, devfn); + if (!addr) { + rcu_read_unlock(); + goto err; + } + + switch (len) { + case 1: + *value = mmio_config_readb(addr + reg); + break; + case 2: + *value = mmio_config_readw(addr + reg); + break; + case 4: + *value = mmio_config_readl(addr + reg); + break; + } + rcu_read_unlock(); + + return 0; +} + +static int pci_mmcfg_write(unsigned int seg, unsigned int bus, + unsigned int devfn, int reg, int len, u32 value) +{ + char __iomem *addr; + + /* Why do we have this when nobody checks it. How about a BUG()!? -AK */ + if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) + return -EINVAL; + + rcu_read_lock(); + addr = pci_dev_base(seg, bus, devfn); + if (!addr) { + rcu_read_unlock(); + return -EINVAL; + } + + switch (len) { + case 1: + mmio_config_writeb(addr + reg, value); + break; + case 2: + mmio_config_writew(addr + reg, value); + break; + case 4: + mmio_config_writel(addr + reg, value); + break; + } + rcu_read_unlock(); + + return 0; +} + +const struct pci_raw_ops pci_mmcfg = { + .read = pci_mmcfg_read, + .write = pci_mmcfg_write, +}; + +static void __iomem *mcfg_ioremap(struct pci_mmcfg_region *cfg) +{ + void __iomem *addr; + u64 start, size; + int num_buses; + + start = cfg->address + PCI_MMCFG_BUS_OFFSET(cfg->start_bus); + num_buses = cfg->end_bus - cfg->start_bus + 1; + size = PCI_MMCFG_BUS_OFFSET(num_buses); + addr = ioremap_nocache(start, size); + if (addr) + addr -= PCI_MMCFG_BUS_OFFSET(cfg->start_bus); + return addr; +} + +int __init pci_mmcfg_arch_init(void) +{ + struct pci_mmcfg_region *cfg; + + list_for_each_entry(cfg, &pci_mmcfg_list, list) + if (pci_mmcfg_arch_map(cfg)) { + pci_mmcfg_arch_free(); + return 0; + } + + raw_pci_ext_ops = &pci_mmcfg; + + return 1; +} + +void __init pci_mmcfg_arch_free(void) +{ + struct pci_mmcfg_region *cfg; + + list_for_each_entry(cfg, &pci_mmcfg_list, list) + pci_mmcfg_arch_unmap(cfg); +} + +int pci_mmcfg_arch_map(struct pci_mmcfg_region *cfg) +{ + cfg->virt = mcfg_ioremap(cfg); + if (!cfg->virt) { + pr_err(PREFIX "can't map MMCONFIG at %pR\n", &cfg->res); + return -ENOMEM; + } + + return 0; +} + +void pci_mmcfg_arch_unmap(struct pci_mmcfg_region *cfg) +{ + if (cfg && cfg->virt) { + iounmap(cfg->virt + PCI_MMCFG_BUS_OFFSET(cfg->start_bus)); + cfg->virt = NULL; + } +} |