[PATCH 1/3] ACPI, APEI: Add 64-bit read/write support for APEI on i386

Myron Stowe
2012-01-21T02:14:06Z

From: Myron Stowe <mstowe@redhat.com>

Base ACPI (CA) currently does not support atomic 64-bit reads and writes
(acpi_read() and acpi_write() split 64-bit loads/stores into two
32-bit transfers) yet APEI expects 64-bit transfer capability, even
when running on 32-bit systems.

This patch implements 64-bit read and write routines for APEI usage.

This patch re-factors similar functionality introduced in commit
04c25997c97, bringing it into the ACPI subsystem in preparation for
removing ./drivers/acpi/atomicio.[ch]. In the implementation I have
replicated acpi_os_read_memory() and acpi_os_write_memory(), creating
64-bit versions for APEI to utilize, as opposed to something more
elegant. My thinking is that we should attempt to see if we can get
ACPI's CA/OSL changed so that the existing acpi_read() and acpi_write()
interfaces are natively 64-bit capable and then subsequently remove the
replication.

Signed-off-by: Myron Stowe <myron.stowe@redhat.com>
---

drivers/acpi/apei/apei-base.c | 35 +-----------
drivers/acpi/osl.c | 116 +++++++++++++++++++++++++++++++++++++++++
include/acpi/acpiosxf.h | 4 +
3 files changed, 124 insertions(+), 31 deletions(-)

diff --git a/drivers/acpi/apei/apei-base.c b/drivers/acpi/apei/apei-base.c
index e45350c..e5d53b7 100644
--- a/drivers/acpi/apei/apei-base.c
+++ b/drivers/acpi/apei/apei-base.c
@@ -596,33 +596,19 @@ int apei_read(u64 *val, struct acpi_generic_address *reg)
{
int rc;
u64 address;
- u32 tmp, width = reg->bit_width;
acpi_status status;

rc = apei_check_gar(reg, &address);
if (rc)
return rc;

- if (width == 64)
- width = 32; /* Break into two 32-bit transfers */
-
*val = 0;
switch(reg->space_id) {
case ACPI_ADR_SPACE_SYSTEM_MEMORY:
- status = acpi_os_read_memory((acpi_physical_address)
- address, &tmp, width);
+ status = acpi_os_read_memory64((acpi_physical_address)
+ address, val, reg->bit_width);
if (ACPI_FAILURE(status))
return -EIO;
- *val = tmp;
-
- if (reg->bit_width == 64) {
- /* Read the top 32 bits */
- status = acpi_os_read_memory((acpi_physical_address)
- (address + 4), &tmp, 32);
- if (ACPI_FAILURE(status))
- return -EIO;
- *val |= ((u64)tmp << 32);
- }
break;
case ACPI_ADR_SPACE_SYSTEM_IO:
status = acpi_os_read_port(address, (u32 *)val, reg->bit_width);
@@ -642,31 +628,18 @@ int apei_write(u64 val, struct acpi_generic_address *reg)
{
int rc;
u64 address;
- u32 width = reg->bit_width;
acpi_status status;

rc = apei_check_gar(reg, &address);
if (rc)
return rc;

- if (width == 64)
- width = 32; /* Break into two 32-bit transfers */
-
switch (reg->space_id) {
case ACPI_ADR_SPACE_SYSTEM_MEMORY:
- status = acpi_os_write_memory((acpi_physical_address)
- address, ACPI_LODWORD(val),
- width);
+ status = acpi_os_write_memory64((acpi_physical_address)
+ address, val, reg->bit_width);
if (ACPI_FAILURE(status))
return -EIO;
-
- if (reg->bit_width == 64) {
- status = acpi_os_write_memory((acpi_physical_address)
- (address + 4),
- ACPI_HIDWORD(val), 32);
- if (ACPI_FAILURE(status))
- return -EIO;
- }
break;
case ACPI_ADR_SPACE_SYSTEM_IO:
status = acpi_os_write_port(address, val, reg->bit_width);
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index fcc12d8..5498a6d 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -710,6 +710,67 @@ acpi_os_read_memory(acpi_physical_address phys_addr, u32 * value, u32 width)
return AE_OK;
}

+#ifdef readq
+static inline u64 read64(const volatile void __iomem *addr)
+{
+ return readq(addr);
+}
+#else
+static inline u64 read64(const volatile void __iomem *addr)
+{
+ u64 l, h;
+ l = readl(addr);
+ h = readl(addr+4);
+ return l | (h << 32);
+}
+#endif
+
+acpi_status
+acpi_os_read_memory64(acpi_physical_address phys_addr, u64 *value, u32 width)
+{
+ void __iomem *virt_addr;
+ unsigned int size = width / 8;
+ bool unmap = false;
+ u64 dummy;
+
+ rcu_read_lock();
+ virt_addr = acpi_map_vaddr_lookup(phys_addr, size);
+ if (!virt_addr) {
+ rcu_read_unlock();
+ virt_addr = acpi_os_ioremap(phys_addr, size);
+ if (!virt_addr)
+ return AE_BAD_ADDRESS;
+ unmap = true;
+ }
+
+ if (!value)
+ value = &dummy;
+
+ switch (width) {
+ case 8:
+ *(u8 *) value = readb(virt_addr);
+ break;
+ case 16:
+ *(u16 *) value = readw(virt_addr);
+ break;
+ case 32:
+ *(u32 *) value = readl(virt_addr);
+ break;
+ case 64:
+ *(u64 *) value = read64(virt_addr);
+ break;
+ default:
+ BUG();
+ }
+
+ if (unmap)
+ iounmap(virt_addr);
+ else
+ rcu_read_unlock();
+
+ return AE_OK;
+}
+
acpi_status
acpi_os_write_memory(acpi_physical_address phys_addr, u32 value, u32 width)
{
@@ -749,6 +810,61 @@ acpi_os_write_memory(acpi_physical_address phys_addr, u32 value, u32 width)
return AE_OK;
}

+#ifdef writeq
+static inline void write64(u64 val, volatile void __iomem *addr)
+{
+ writeq(val, addr);
+}
+#else
+static inline void write64(u64 val, volatile void __iomem *addr)
+{
+ writel(val, addr);
+ writel(val>>32, addr+4);
+}
+#endif
+
+acpi_status
+acpi_os_write_memory64(acpi_physical_address phys_addr, u64 value, u32 width)
+{
+ void __iomem *virt_addr;
+ unsigned int size = width / 8;
+ bool unmap = false;
+
+ rcu_read_lock();
+ virt_addr = acpi_map_vaddr_lookup(phys_addr, size);
+ if (!virt_addr) {
+ rcu_read_unlock();
+ virt_addr = acpi_os_ioremap(phys_addr, size);
+ if (!virt_addr)
+ return AE_BAD_ADDRESS;
+ unmap = true;
+ }
+
+ switch (width) {
+ case 8:
+ writeb(value, virt_addr);
+ break;
+ case 16:
+ writew(value, virt_addr);
+ break;
+ case 32:
+ writel(value, virt_addr);
+ break;
+ case 64:
+ write64(value, virt_addr);
+ break;
+ default:
+ BUG();
+ }
+
+ if (unmap)
+ iounmap(virt_addr);
+ else
+ rcu_read_unlock();
+
+ return AE_OK;
+}
+
acpi_status
acpi_os_read_pci_configuration(struct acpi_pci_id * pci_id, u32 reg,
u64 *value, u32 width)
diff --git a/include/acpi/acpiosxf.h b/include/acpi/acpiosxf.h
index 2fe8639..7c9aebe 100644
--- a/include/acpi/acpiosxf.h
+++ b/include/acpi/acpiosxf.h
@@ -218,9 +218,13 @@ acpi_status acpi_os_write_port(acpi_io_address address, u32 value, u32 width);
*/
acpi_status
acpi_os_read_memory(acpi_physical_address address, u32 * value, u32 width);
+acpi_status
+acpi_os_read_memory64(acpi_physical_address address, u64 *value, u32 width);

acpi_status
acpi_os_write_memory(acpi_physical_address address, u32 value, u32 width);
+acpi_status
+acpi_os_write_memory64(acpi_physical_address address, u64 value, u32 width);

/*
* Platform and hardware-independent PCI configuration space access