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-rw-r--r--drivers/acpi/atomicio.c360
1 files changed, 360 insertions, 0 deletions
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, &reg->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);
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