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Subject[PATCH v5 03/22] ACPI: CPPC: implement support for SystemIO registers
Date
From: Steven Noonan <steven@valvesoftware.com>

According to the ACPI v6.2 (and later) specification, SystemIO can be
used for _CPC registers. This teaches cppc_acpi how to handle such
registers.

This patch was tested using the amd_pstate driver on my Zephyrus G15
(model GA503QS) using the current version 410 BIOS, which uses
a SystemIO register for the HighestPerformance element in _CPC.

Signed-off-by: Steven Noonan <steven@valvesoftware.com>
Signed-off-by: Huang Rui <ray.huang@amd.com>
---
drivers/acpi/cppc_acpi.c | 46 +++++++++++++++++++++++++++++++++++++---
1 file changed, 43 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index a85c351589be..ca62c3dc9899 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -746,9 +746,24 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
goto out_free;
cpc_ptr->cpc_regs[i-2].sys_mem_vaddr = addr;
}
+ } else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
+ if (gas_t->access_width < 1 || gas_t->access_width > 3) {
+ /* 1 = 8-bit, 2 = 16-bit, and 3 = 32-bit. SystemIO doesn't
+ * implement 64-bit registers.
+ */
+ pr_debug("Invalid access width %d for SystemIO register\n",
+ gas_t->access_width);
+ goto out_free;
+ }
+ if (gas_t->address & ~0xFFFFULL) {
+ /* SystemIO registers use 16-bit integer addresses */
+ pr_debug("Invalid IO port %llu for SystemIO register\n",
+ gas_t->address);
+ goto out_free;
+ }
} else {
if (gas_t->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE || !cpc_ffh_supported()) {
- /* Support only PCC ,SYS MEM and FFH type regs */
+ /* Support only PCC, SystemMemory, SystemIO, and FFH type regs. */
pr_debug("Unsupported register type: %d\n", gas_t->space_id);
goto out_free;
}
@@ -923,7 +938,20 @@ 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)
+
+ if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
+ u32 width = 8 << (reg->access_width - 1);
+ acpi_status status;
+
+ status = acpi_os_read_port((acpi_io_address)reg->address, (u32 *)val, width);
+
+ if (status != AE_OK) {
+ pr_debug("Error: Failed to read SystemIO port %llx\n", reg->address);
+ return -EFAULT;
+ }
+
+ return 0;
+ } else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
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;
@@ -962,7 +990,19 @@ 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 = &reg_res->cpc_entry.reg;

- if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
+ if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
+ u32 width = 8 << (reg->access_width - 1);
+ acpi_status status;
+
+ status = acpi_os_write_port((acpi_io_address)reg->address, (u32)val, width);
+
+ if (status != AE_OK) {
+ pr_debug("Error: Failed to write SystemIO port %llx\n", reg->address);
+ return -EFAULT;
+ }
+
+ return 0;
+ } else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
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;
--
2.25.1
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