Re: [PATCH 2/6] x86, acpi, pci: Move arch-agnostic MMCFG code out of arch/x86/ directory

Bjorn Helgaas
2014-12-10T23:55:07Z

On Wed, Nov 19, 2014 at 05:04:47PM +0100, Tomasz Nowicki wrote:
> MMCFG table seems to be architecture independent and it makes sense
> to share common code across all architectures. The ones that may need
> architectural specific actions have default prototype (__weak).
>
> Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org>
> Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
> ---
> arch/x86/include/asm/pci_x86.h | 29 -----
> arch/x86/pci/acpi.c | 1 +
> arch/x86/pci/init.c | 1 +
> arch/x86/pci/mmconfig-shared.c | 200 +---------------------------------
> arch/x86/pci/mmconfig_32.c | 1 +
> arch/x86/pci/mmconfig_64.c | 1 +
> drivers/acpi/Makefile | 1 +
> drivers/acpi/bus.c | 1 +
> drivers/acpi/mmconfig.c | 242 +++++++++++++++++++++++++++++++++++++++++
> include/linux/mmconfig.h | 58 ++++++++++
> include/linux/pci.h | 8 --
> 11 files changed, 308 insertions(+), 235 deletions(-)
> create mode 100644 drivers/acpi/mmconfig.c
> create mode 100644 include/linux/mmconfig.h
> ...

Much of the code you're moving to drivers/acpi/mmconfig.c is not actually
ACPI-specific and would have to be duplicated for a non-ACPI architecture
that supports ECAM. Could that code be moved somewhere like
drivers/pci/ecam.c, where it could be shared?

Bjorn

> diff --git a/drivers/acpi/mmconfig.c b/drivers/acpi/mmconfig.c
> new file mode 100644
> index 0000000..d62dccda
> --- /dev/null
> +++ b/drivers/acpi/mmconfig.c
> @@ -0,0 +1,242 @@
> +/*
> + * Arch agnostic low-level direct PCI config space access via MMCONFIG
> + *
> + * Per-architecture code takes care of the mappings, region validation and
> + * accesses themselves.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + */
> +
> +#include <linux/mutex.h>
> +#include <linux/rculist.h>
> +#include <linux/mmconfig.h>
> +
> +#define PREFIX "PCI: "
> +
> +static DEFINE_MUTEX(pci_mmcfg_lock);
> +
> +LIST_HEAD(pci_mmcfg_list);
> +
> +static void __init pci_mmconfig_remove(struct pci_mmcfg_region *cfg)
> +{
> + if (cfg->res.parent)
> + release_resource(&cfg->res);
> + list_del(&cfg->list);
> + kfree(cfg);
> +}
> +
> +void __init free_all_mmcfg(void)
> +{
> + struct pci_mmcfg_region *cfg, *tmp;
> +
> + pci_mmcfg_arch_free();
> + list_for_each_entry_safe(cfg, tmp, &pci_mmcfg_list, list)
> + pci_mmconfig_remove(cfg);
> +}
> +
> +void list_add_sorted(struct pci_mmcfg_region *new)
> +{
> + struct pci_mmcfg_region *cfg;
> +
> + /* keep list sorted by segment and starting bus number */
> + list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list) {
> + if (cfg->segment > new->segment ||
> + (cfg->segment == new->segment &&
> + cfg->start_bus >= new->start_bus)) {
> + list_add_tail_rcu(&new->list, &cfg->list);
> + return;
> + }
> + }
> + list_add_tail_rcu(&new->list, &pci_mmcfg_list);
> +}
> +
> +struct pci_mmcfg_region *pci_mmconfig_alloc(int segment, int start,
> + int end, u64 addr)
> +{
> + struct pci_mmcfg_region *new;
> + struct resource *res;
> +
> + if (addr == 0)
> + return NULL;
> +
> + new = kzalloc(sizeof(*new), GFP_KERNEL);
> + if (!new)
> + return NULL;
> +
> + new->address = addr;
> + new->segment = segment;
> + new->start_bus = start;
> + new->end_bus = end;
> +
> + res = &new->res;
> + res->start = addr + PCI_MMCFG_BUS_OFFSET(start);
> + res->end = addr + PCI_MMCFG_BUS_OFFSET(end + 1) - 1;
> + res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> + snprintf(new->name, PCI_MMCFG_RESOURCE_NAME_LEN,
> + "PCI MMCONFIG %04x [bus %02x-%02x]", segment, start, end);
> + res->name = new->name;
> +
> + return new;
> +}
> +
> +struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
> + int end, u64 addr)
> +{
> + struct pci_mmcfg_region *new;
> +
> + new = pci_mmconfig_alloc(segment, start, end, addr);
> + if (new) {
> + mutex_lock(&pci_mmcfg_lock);
> + list_add_sorted(new);
> + mutex_unlock(&pci_mmcfg_lock);
> +
> + pr_info(PREFIX
> + "MMCONFIG for domain %04x [bus %02x-%02x] at %pR "
> + "(base %#lx)\n",
> + segment, start, end, &new->res, (unsigned long)addr);
> + }
> +
> + return new;
> +}
> +
> +int __init pci_mmconfig_inject(struct pci_mmcfg_region *cfg)
> +{
> + struct pci_mmcfg_region *cfg_conflict;
> + int err = 0;
> +
> + mutex_lock(&pci_mmcfg_lock);
> + cfg_conflict = pci_mmconfig_lookup(cfg->segment, cfg->start_bus);
> + if (cfg_conflict) {
> + if (cfg_conflict->end_bus < cfg->end_bus)
> + pr_info(FW_INFO "MMCONFIG for "
> + "domain %04x [bus %02x-%02x] "
> + "only partially covers this bridge\n",
> + cfg_conflict->segment, cfg_conflict->start_bus,
> + cfg_conflict->end_bus);
> + err = -EEXIST;
> + goto out;
> + }
> +
> + if (pci_mmcfg_arch_map(cfg)) {
> + pr_warn("fail to map MMCONFIG %pR.\n", &cfg->res);
> + err = -ENOMEM;
> + goto out;
> + } else {
> + list_add_sorted(cfg);
> + pr_info("MMCONFIG at %pR (base %#lx)\n",
> + &cfg->res, (unsigned long)cfg->address);
> +
> + }
> +out:
> + mutex_unlock(&pci_mmcfg_lock);
> + return err;
> +}
> +
> +struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus)
> +{
> + struct pci_mmcfg_region *cfg;
> +
> + list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
> + if (cfg->segment == segment &&
> + cfg->start_bus <= bus && bus <= cfg->end_bus)
> + return cfg;
> +
> + return NULL;
> +}
> +
> +int __init __weak acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
> + struct acpi_mcfg_allocation *cfg)
> +{
> + return 0;
> +}
> +
> +int __init pci_parse_mcfg(struct acpi_table_header *header)
> +{
> + struct acpi_table_mcfg *mcfg;
> + struct acpi_mcfg_allocation *cfg_table, *cfg;
> + unsigned long i;
> + int entries;
> +
> + if (!header)
> + return -EINVAL;
> +
> + mcfg = (struct acpi_table_mcfg *)header;
> +
> + /* how many config structures do we have */
> + free_all_mmcfg();
> + entries = 0;
> + i = header->length - sizeof(struct acpi_table_mcfg);
> + while (i >= sizeof(struct acpi_mcfg_allocation)) {
> + entries++;
> + i -= sizeof(struct acpi_mcfg_allocation);
> + }
> + if (entries == 0) {
> + pr_err(PREFIX "MMCONFIG has no entries\n");
> + return -ENODEV;
> + }
> +
> + cfg_table = (struct acpi_mcfg_allocation *) &mcfg[1];
> + for (i = 0; i < entries; i++) {
> + cfg = &cfg_table[i];
> + if (acpi_mcfg_check_entry(mcfg, cfg)) {
> + free_all_mmcfg();
> + return -ENODEV;
> + }
> +
> + if (pci_mmconfig_add(cfg->pci_segment, cfg->start_bus_number,
> + cfg->end_bus_number, cfg->address) == NULL) {
> + pr_warn(PREFIX "no memory for MCFG entries\n");
> + free_all_mmcfg();
> + return -ENOMEM;
> + }
> + }
> +
> + return 0;
> +}
> +
> +/* Delete MMCFG information for host bridges */
> +int pci_mmconfig_delete(u16 seg, u8 start, u8 end)
> +{
> + struct pci_mmcfg_region *cfg;
> +
> + mutex_lock(&pci_mmcfg_lock);
> + list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
> + if (cfg->segment == seg && cfg->start_bus == start &&
> + cfg->end_bus == end) {
> + list_del_rcu(&cfg->list);
> + synchronize_rcu();
> + pci_mmcfg_arch_unmap(cfg);
> + if (cfg->res.parent)
> + release_resource(&cfg->res);
> + mutex_unlock(&pci_mmcfg_lock);
> + kfree(cfg);
> + return 0;
> + }
> + mutex_unlock(&pci_mmcfg_lock);
> +
> + return -ENOENT;
> +}
> +
> +void __init __weak pci_mmcfg_early_init(void)
> +{
> +
> +}
> +
> +void __init __weak pci_mmcfg_late_init(void)
> +{
> + struct pci_mmcfg_region *cfg;
> +
> + acpi_table_parse(ACPI_SIG_MCFG, pci_parse_mcfg);
> +
> + if (list_empty(&pci_mmcfg_list))
> + return;
> +
> + if (!pci_mmcfg_arch_init())
> + free_all_mmcfg();
> +
> + list_for_each_entry(cfg, &pci_mmcfg_list, list)
> + insert_resource(&iomem_resource, &cfg->res);
> +}
> diff --git a/include/linux/mmconfig.h b/include/linux/mmconfig.h
> new file mode 100644
> index 0000000..6ccd1ee
> --- /dev/null
> +++ b/include/linux/mmconfig.h
> @@ -0,0 +1,58 @@
> +#ifndef __MMCONFIG_H
> +#define __MMCONFIG_H
> +#ifdef __KERNEL__
> +
> +#include <linux/types.h>
> +#include <linux/acpi.h>
> +
> +#ifdef CONFIG_PCI_MMCONFIG
> +/* "PCI MMCONFIG %04x [bus %02x-%02x]" */
> +#define PCI_MMCFG_RESOURCE_NAME_LEN (22 + 4 + 2 + 2)
> +
> +struct pci_mmcfg_region {
> + struct list_head list;
> + struct resource res;
> + u64 address;
> + char __iomem *virt;
> + u16 segment;
> + u8 start_bus;
> + u8 end_bus;
> + char name[PCI_MMCFG_RESOURCE_NAME_LEN];
> +};
> +
> +void pci_mmcfg_early_init(void);
> +void pci_mmcfg_late_init(void);
> +struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus);
> +
> +int pci_parse_mcfg(struct acpi_table_header *header);
> +struct pci_mmcfg_region *pci_mmconfig_alloc(int segment, int start,
> + int end, u64 addr);
> +int pci_mmconfig_inject(struct pci_mmcfg_region *cfg);
> +struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
> + int end, u64 addr);
> +void list_add_sorted(struct pci_mmcfg_region *new);
> +int acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
> + struct acpi_mcfg_allocation *cfg);
> +void free_all_mmcfg(void);
> +int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
> + phys_addr_t addr);
> +int pci_mmconfig_delete(u16 seg, u8 start, u8 end);
> +
> +/* Arch specific calls */
> +int pci_mmcfg_arch_init(void);
> +void pci_mmcfg_arch_free(void);
> +int pci_mmcfg_arch_map(struct pci_mmcfg_region *cfg);
> +void pci_mmcfg_arch_unmap(struct pci_mmcfg_region *cfg);
> +
> +extern struct list_head pci_mmcfg_list;
> +
> +#define PCI_MMCFG_BUS_OFFSET(bus) ((bus) << 20)
> +#else /* CONFIG_PCI_MMCONFIG */
> +static inline void pci_mmcfg_late_init(void) { }
> +static inline void pci_mmcfg_early_init(void) { }
> +static inline void *pci_mmconfig_lookup(int segment, int bus)
> +{ return NULL; }
> +#endif /* CONFIG_PCI_MMCONFIG */
> +
> +#endif /* __KERNEL__ */
> +#endif /* __MMCONFIG_H */
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 6afba72..0a8b82e 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1658,14 +1658,6 @@ void pcibios_release_device(struct pci_dev *dev);
> extern struct dev_pm_ops pcibios_pm_ops;
> #endif
>
> -#ifdef CONFIG_PCI_MMCONFIG
> -void __init pci_mmcfg_early_init(void);
> -void __init pci_mmcfg_late_init(void);
> -#else
> -static inline void pci_mmcfg_early_init(void) { }
> -static inline void pci_mmcfg_late_init(void) { }
> -#endif
> -
> int pci_ext_cfg_avail(void);
>
> void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar);
> --
> 1.9.1
>