Revert "Revert "ACPI: CPPC: Use access_width over bit_width for system memory accesses""

This reverts commit b54c4632946ae42f2b39ed38abd909bbf78cbcc2 which was a
revert of a backport of commit 2f4a4d63a193be6fd530d180bb13c3592052904c
upstream to 5.15.y.

Cc: Jarred White <jarredwhite@linux.microsoft.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Vanshidhar Konda <vanshikonda@os.amperecomputing.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Easwar Hariharan <eahariha@linux.microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 7cc9183c8dc8eb0bd28cb09be61707f347ab6223..408b1fda5702d578042f9b3f1430a0d38c9c4b5c 100644 (file)
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -161,6 +161,13 @@ show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_freq);
 show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, reference_perf);
 show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, wraparound_time);
 
+/* Check for valid access_width, otherwise, fallback to using bit_width */
+#define GET_BIT_WIDTH(reg) ((reg)->access_width ? (8 << ((reg)->access_width - 1)) : (reg)->bit_width)
+
+/* Shift and apply the mask for CPC reads/writes */
+#define MASK_VAL(reg, val) ((val) >> ((reg)->bit_offset &                      \
+                                       GENMASK(((reg)->bit_width), 0)))
+
 static ssize_t show_feedback_ctrs(struct kobject *kobj,
                struct kobj_attribute *attr, char *buf)
 {
@@ -762,8 +769,10 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
                        } else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
                                if (gas_t->address) {
                                        void __iomem *addr;
+                                       size_t access_width;
 
-                                       addr = ioremap(gas_t->address, gas_t->bit_width/8);
+                                       access_width = GET_BIT_WIDTH(gas_t) / 8;
+                                       addr = ioremap(gas_t->address, access_width);
                                        if (!addr)
                                                goto out_free;
                                        cpc_ptr->cpc_regs[i-2].sys_mem_vaddr = addr;
@@ -936,6 +945,7 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
 {
        int ret_val = 0;
        void __iomem *vaddr = NULL;
+       int size;
        int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
        struct cpc_reg *reg = &reg_res->cpc_entry.reg;
 
@@ -955,7 +965,9 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
                return acpi_os_read_memory((acpi_physical_address)reg->address,
                                val, reg->bit_width);
 
-       switch (reg->bit_width) {
+       size = GET_BIT_WIDTH(reg);
+
+       switch (size) {
        case 8:
                *val = readb_relaxed(vaddr);
                break;
@@ -974,12 +986,16 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
                ret_val = -EFAULT;
        }
 
+       if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+               *val = MASK_VAL(reg, *val);
+
        return ret_val;
 }
 
 static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
 {
        int ret_val = 0;
+       int size;
        void __iomem *vaddr = NULL;
        int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
        struct cpc_reg *reg = &reg_res->cpc_entry.reg;
@@ -994,7 +1010,12 @@ static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
                return acpi_os_write_memory((acpi_physical_address)reg->address,
                                val, reg->bit_width);
 
-       switch (reg->bit_width) {
+       size = GET_BIT_WIDTH(reg);
+
+       if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+               val = MASK_VAL(reg, val);
+
+       switch (size) {
        case 8:
                writeb_relaxed(val, vaddr);
                break;