diff options
| -rw-r--r-- | drivers/acpi/Makefile | 1 | ||||
| -rw-r--r-- | drivers/acpi/atomicio.c | 360 | ||||
| -rw-r--r-- | include/acpi/atomicio.h | 10 |
3 files changed, 371 insertions, 0 deletions
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile index a8d8998dd5c5..93251fb599fa 100644 --- a/drivers/acpi/Makefile +++ b/drivers/acpi/Makefile @@ -19,6 +19,7 @@ obj-y += acpi.o \ # All the builtin files are in the "acpi." module_param namespace. acpi-y += osl.o utils.o reboot.o +acpi-y += atomicio.o acpi-y += hest.o # sleep related files diff --git a/drivers/acpi/atomicio.c b/drivers/acpi/atomicio.c new file mode 100644 index 000000000000..814b19249616 --- /dev/null +++ b/drivers/acpi/atomicio.c @@ -0,0 +1,360 @@ +/* + * atomicio.c - ACPI IO memory pre-mapping/post-unmapping, then + * accessing in atomic context. + * + * This is used for NMI handler to access IO memory area, because + * ioremap/iounmap can not be used in NMI handler. The IO memory area + * is pre-mapped in process context and accessed in NMI handler. + * + * Copyright (C) 2009-2010, Intel Corp. + * Author: Huang Ying <ying.huang@intel.com> + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/acpi.h> +#include <linux/io.h> +#include <linux/kref.h> +#include <linux/rculist.h> +#include <linux/interrupt.h> +#include <acpi/atomicio.h> + +#define ACPI_PFX "ACPI: " + +static LIST_HEAD(acpi_iomaps); +/* + * Used for mutual exclusion between writers of acpi_iomaps list, for + * synchronization between readers and writer, RCU is used. + */ +static DEFINE_SPINLOCK(acpi_iomaps_lock); + +struct acpi_iomap { + struct list_head list; + void __iomem *vaddr; + unsigned long size; + phys_addr_t paddr; + struct kref ref; +}; + +/* acpi_iomaps_lock or RCU read lock must be held before calling */ +static struct acpi_iomap *__acpi_find_iomap(phys_addr_t paddr, + unsigned long size) +{ + struct acpi_iomap *map; + + list_for_each_entry_rcu(map, &acpi_iomaps, list) { + if (map->paddr + map->size >= paddr + size && + map->paddr <= paddr) + return map; + } + return NULL; +} + +/* + * Atomic "ioremap" used by NMI handler, if the specified IO memory + * area is not pre-mapped, NULL will be returned. + * + * acpi_iomaps_lock or RCU read lock must be held before calling + */ +static void __iomem *__acpi_ioremap_fast(phys_addr_t paddr, + unsigned long size) +{ + struct acpi_iomap *map; + + map = __acpi_find_iomap(paddr, size); + if (map) + return map->vaddr + (paddr - map->paddr); + else + return NULL; +} + +/* acpi_iomaps_lock must be held before calling */ +static void __iomem *__acpi_try_ioremap(phys_addr_t paddr, + unsigned long size) +{ + struct acpi_iomap *map; + + map = __acpi_find_iomap(paddr, size); + if (map) { + kref_get(&map->ref); + return map->vaddr + (paddr - map->paddr); + } else + return NULL; +} + +/* + * Used to pre-map the specified IO memory area. First try to find + * whether the area is already pre-mapped, if it is, increase the + * reference count (in __acpi_try_ioremap) and return; otherwise, do + * the real ioremap, and add the mapping into acpi_iomaps list. + */ +static void __iomem *acpi_pre_map(phys_addr_t paddr, + unsigned long size) +{ + void __iomem *vaddr; + struct acpi_iomap *map; + unsigned long pg_sz, flags; + phys_addr_t pg_off; + + spin_lock_irqsave(&acpi_iomaps_lock, flags); + vaddr = __acpi_try_ioremap(paddr, size); + spin_unlock_irqrestore(&acpi_iomaps_lock, flags); + if (vaddr) + return vaddr; + + pg_off = paddr & PAGE_MASK; + pg_sz = ((paddr + size + PAGE_SIZE - 1) & PAGE_MASK) - pg_off; + vaddr = ioremap(pg_off, pg_sz); + if (!vaddr) + return NULL; + map = kmalloc(sizeof(*map), GFP_KERNEL); + if (!map) + goto err_unmap; + INIT_LIST_HEAD(&map->list); + map->paddr = pg_off; + map->size = pg_sz; + map->vaddr = vaddr; + kref_init(&map->ref); + + spin_lock_irqsave(&acpi_iomaps_lock, flags); + vaddr = __acpi_try_ioremap(paddr, size); + if (vaddr) { + spin_unlock_irqrestore(&acpi_iomaps_lock, flags); + iounmap(map->vaddr); + kfree(map); + return vaddr; + } + list_add_tail_rcu(&map->list, &acpi_iomaps); + spin_unlock_irqrestore(&acpi_iomaps_lock, flags); + + return vaddr + (paddr - pg_off); +err_unmap: + iounmap(vaddr); + return NULL; +} + +/* acpi_iomaps_lock must be held before calling */ +static void __acpi_kref_del_iomap(struct kref *ref) +{ + struct acpi_iomap *map; + + map = container_of(ref, struct acpi_iomap, ref); + list_del_rcu(&map->list); +} + +/* + * Used to post-unmap the specified IO memory area. The iounmap is + * done only if the reference count goes zero. + */ +static void acpi_post_unmap(phys_addr_t paddr, unsigned long size) +{ + struct acpi_iomap *map; + unsigned long flags; + int del; + + spin_lock_irqsave(&acpi_iomaps_lock, flags); + map = __acpi_find_iomap(paddr, size); + BUG_ON(!map); + del = kref_put(&map->ref, __acpi_kref_del_iomap); + spin_unlock_irqrestore(&acpi_iomaps_lock, flags); + + if (!del) + return; + + synchronize_rcu(); + iounmap(map->vaddr); + kfree(map); +} + +/* In NMI handler, should set silent = 1 */ +static int acpi_check_gar(struct acpi_generic_address *reg, + u64 *paddr, int silent) +{ + u32 width, space_id; + + width = reg->bit_width; + space_id = reg->space_id; + /* Handle possible alignment issues */ + memcpy(paddr, ®->address, sizeof(*paddr)); + if (!*paddr) { + if (!silent) + pr_warning(FW_BUG ACPI_PFX + "Invalid physical address in GAR [0x%llx/%u/%u]\n", + *paddr, width, space_id); + return -EINVAL; + } + + if ((width != 8) && (width != 16) && (width != 32) && (width != 64)) { + if (!silent) + pr_warning(FW_BUG ACPI_PFX + "Invalid bit width in GAR [0x%llx/%u/%u]\n", + *paddr, width, space_id); + return -EINVAL; + } + + if (space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY && + space_id != ACPI_ADR_SPACE_SYSTEM_IO) { + if (!silent) + pr_warning(FW_BUG ACPI_PFX + "Invalid address space type in GAR [0x%llx/%u/%u]\n", + *paddr, width, space_id); + return -EINVAL; + } + + return 0; +} + +/* Pre-map, working on GAR */ +int acpi_pre_map_gar(struct acpi_generic_address *reg) +{ + u64 paddr; + void __iomem *vaddr; + int rc; + + if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) + return 0; + + rc = acpi_check_gar(reg, &paddr, 0); + if (rc) + return rc; + + vaddr = acpi_pre_map(paddr, reg->bit_width / 8); + if (!vaddr) + return -EIO; + + return 0; +} +EXPORT_SYMBOL_GPL(acpi_pre_map_gar); + +/* Post-unmap, working on GAR */ +int acpi_post_unmap_gar(struct acpi_generic_address *reg) +{ + u64 paddr; + int rc; + + if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) + return 0; + + rc = acpi_check_gar(reg, &paddr, 0); + if (rc) + return rc; + + acpi_post_unmap(paddr, reg->bit_width / 8); + + return 0; +} +EXPORT_SYMBOL_GPL(acpi_post_unmap_gar); + +/* + * Can be used in atomic (including NMI) or process context. RCU read + * lock can only be released after the IO memory area accessing. + */ +static int acpi_atomic_read_mem(u64 paddr, u64 *val, u32 width) +{ + void __iomem *addr; + + rcu_read_lock(); + addr = __acpi_ioremap_fast(paddr, width); + switch (width) { + case 8: + *val = readb(addr); + break; + case 16: + *val = readw(addr); + break; + case 32: + *val = readl(addr); + break; + case 64: + *val = readq(addr); + break; + default: + return -EINVAL; + } + rcu_read_unlock(); + + return 0; +} + +static int acpi_atomic_write_mem(u64 paddr, u64 val, u32 width) +{ + void __iomem *addr; + + rcu_read_lock(); + addr = __acpi_ioremap_fast(paddr, width); + switch (width) { + case 8: + writeb(val, addr); + break; + case 16: + writew(val, addr); + break; + case 32: + writel(val, addr); + break; + case 64: + writeq(val, addr); + break; + default: + return -EINVAL; + } + rcu_read_unlock(); + + return 0; +} + +/* GAR accessing in atomic (including NMI) or process context */ +int acpi_atomic_read(u64 *val, struct acpi_generic_address *reg) +{ + u64 paddr; + int rc; + + rc = acpi_check_gar(reg, &paddr, 1); + if (rc) + return rc; + + *val = 0; + switch (reg->space_id) { + case ACPI_ADR_SPACE_SYSTEM_MEMORY: + return acpi_atomic_read_mem(paddr, val, reg->bit_width); + case ACPI_ADR_SPACE_SYSTEM_IO: + return acpi_os_read_port(paddr, (u32 *)val, reg->bit_width); + default: + return -EINVAL; + } +} +EXPORT_SYMBOL_GPL(acpi_atomic_read); + +int acpi_atomic_write(u64 val, struct acpi_generic_address *reg) +{ + u64 paddr; + int rc; + + rc = acpi_check_gar(reg, &paddr, 1); + if (rc) + return rc; + + switch (reg->space_id) { + case ACPI_ADR_SPACE_SYSTEM_MEMORY: + return acpi_atomic_write_mem(paddr, val, reg->bit_width); + case ACPI_ADR_SPACE_SYSTEM_IO: + return acpi_os_write_port(paddr, val, reg->bit_width); + default: + return -EINVAL; + } +} +EXPORT_SYMBOL_GPL(acpi_atomic_write); diff --git a/include/acpi/atomicio.h b/include/acpi/atomicio.h new file mode 100644 index 000000000000..8b9fb4b0b9ce --- /dev/null +++ b/include/acpi/atomicio.h @@ -0,0 +1,10 @@ +#ifndef ACPI_ATOMIC_IO_H +#define ACPI_ATOMIC_IO_H + +int acpi_pre_map_gar(struct acpi_generic_address *reg); +int acpi_post_unmap_gar(struct acpi_generic_address *reg); + +int acpi_atomic_read(u64 *val, struct acpi_generic_address *reg); +int acpi_atomic_write(u64 val, struct acpi_generic_address *reg); + +#endif |
