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ACPICA: acpi_read: On error, do not modify the return value target location.

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If an error happens in the middle of a split 32/32 64-bit I/O
operation, do not modify the target of the return value pointer.
Makes the code consistent with the rest of ACPICA. Bjorn Helgaas.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Reviewed-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Bjorn Helgaas 2013-09-23 09:51:22 +08:00 • committed by Rafael J. Wysocki
commit c3faedcdb4
1 changed files with 14 additions and 12 deletions
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26
drivers/acpi/acpica/hwxface.c
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@ -119,7 +119,8 @@ ACPI_EXPORT_SYMBOL(acpi_reset)
******************************************************************************/
acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg)
{
u32 value;
u32 value_lo;
u32 value_hi;
u32 width;
u64 address;
acpi_status status;
@ -137,13 +138,8 @@ acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg)
return (status);
}
/* Initialize entire 64-bit return value to zero */
*return_value = 0;
value = 0;
/*
* Two address spaces supported: Memory or IO. PCI_Config is
* Two address spaces supported: Memory or I/O. PCI_Config is
* not supported here because the GAS structure is insufficient
*/
if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
@ -155,29 +151,35 @@ acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg)
}
} else { /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
value_lo = 0;
value_hi = 0;
width = reg->bit_width;
if (width == 64) {
width = 32; /* Break into two 32-bit transfers */
}
status = acpi_hw_read_port((acpi_io_address)
address, &value, width);
address, &value_lo, width);
if (ACPI_FAILURE(status)) {
return (status);
}
*return_value = value;
if (reg->bit_width == 64) {
/* Read the top 32 bits */
status = acpi_hw_read_port((acpi_io_address)
(address + 4), &value, 32);
(address + 4), &value_hi,
32);
if (ACPI_FAILURE(status)) {
return (status);
}
*return_value |= ((u64)value << 32);
}
/* Set the return value only if status is AE_OK */
*return_value = (value_lo | ((u64)value_hi << 32));
}
ACPI_DEBUG_PRINT((ACPI_DB_IO,
@ -186,7 +188,7 @@ acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg)
ACPI_FORMAT_UINT64(address),
acpi_ut_get_region_name(reg->space_id)));
return (status);
return (AE_OK);
}
ACPI_EXPORT_SYMBOL(acpi_read)