From: Vanshidhar Konda vanshikonda@os.amperecomputing.com
commit f489c948028b69cea235d9c0de1cc10eeb26a172 upstream
commit 2f4a4d63a193 ("ACPI: CPPC: Use access_width over bit_width for system memory accesses") modified cpc_read()/cpc_write() to use access_width to read CPC registers.
However, for PCC registers the access width field in the ACPI register macro specifies the PCC subspace ID. For non-zero PCC subspace ID it is incorrectly treated as access width. This causes errors when reading from PCC registers in the CPPC driver.
For PCC registers, base the size of read/write on the bit width field. The debug message in cpc_read()/cpc_write() is updated to print relevant information for the address space type used to read the register.
Fixes: 2f4a4d63a193 ("ACPI: CPPC: Use access_width over bit_width for system memory accesses") Signed-off-by: Vanshidhar Konda vanshikonda@os.amperecomputing.com Tested-by: Jarred White jarredwhite@linux.microsoft.com Reviewed-by: Jarred White jarredwhite@linux.microsoft.com Reviewed-by: Easwar Hariharan eahariha@linux.microsoft.com Cc: 5.15+ stable@vger.kernel.org # 5.15+ Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com [ eahariha: Backport to v5.15 by dropping SystemIO bits as commit a2c8f92bea5f is not present ] Signed-off-by: Easwar Hariharan eahariha@linux.microsoft.com --- drivers/acpi/cppc_acpi.c | 48 ++++++++++++++++++++++++++++++---------- 1 file changed, 36 insertions(+), 12 deletions(-)
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index 6aa456cda0ed9..6dcce036adb9c 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -955,17 +955,24 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val) }
*val = 0; - if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0) + size = GET_BIT_WIDTH(reg); + + if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0) { + /* + * For registers in PCC space, the register size is determined + * by the bit width field; the access size is used to indicate + * the PCC subspace id. + */ + size = reg->bit_width; vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id); + } else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) vaddr = reg_res->sys_mem_vaddr; else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) return cpc_read_ffh(cpu, reg, val); else return acpi_os_read_memory((acpi_physical_address)reg->address, - val, reg->bit_width); - - size = GET_BIT_WIDTH(reg); + val, size);
switch (size) { case 8: @@ -981,8 +988,13 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val) *val = readq_relaxed(vaddr); break; default: - pr_debug("Error: Cannot read %u bit width from PCC for ss: %d\n", - reg->bit_width, pcc_ss_id); + if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { + pr_debug("Error: Cannot read %u bit width from system memory: 0x%llx\n", + size, reg->address); + } else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) { + pr_debug("Error: Cannot read %u bit width from PCC for ss: %d\n", + size, pcc_ss_id); + } ret_val = -EFAULT; }
@@ -1000,17 +1012,24 @@ static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val) int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu); struct cpc_reg *reg = ®_res->cpc_entry.reg;
- if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0) + size = GET_BIT_WIDTH(reg); + + if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0) { + /* + * For registers in PCC space, the register size is determined + * by the bit width field; the access size is used to indicate + * the PCC subspace id. + */ + size = reg->bit_width; vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id); + } else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) vaddr = reg_res->sys_mem_vaddr; else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) return cpc_write_ffh(cpu, reg, val); else return acpi_os_write_memory((acpi_physical_address)reg->address, - val, reg->bit_width); - - size = GET_BIT_WIDTH(reg); + val, size);
if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) val = MASK_VAL(reg, val); @@ -1029,8 +1048,13 @@ static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val) writeq_relaxed(val, vaddr); break; default: - pr_debug("Error: Cannot write %u bit width to PCC for ss: %d\n", - reg->bit_width, pcc_ss_id); + if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { + pr_debug("Error: Cannot write %u bit width to system memory: 0x%llx\n", + size, reg->address); + } else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) { + pr_debug("Error: Cannot write %u bit width to PCC for ss: %d\n", + size, pcc_ss_id); + } ret_val = -EFAULT; break; }