ACPI / CPPC: Add support for functional fixed hardware address

The CPPC registers can also be accessed via functional fixed hardware
addresse(FFH) in X86. Add support by modifying cpc_read and cpc_write to
be able to read/write MSRs on x86 platform on per cpu basis.
Also with this change, acpi_cppc_processor_probe doesn't bail out if
address space id is not equal to PCC or memory address space and FFH
is supported on the system.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 62 insertions, 13 deletions

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index ed58883d35ee..715fe8001d59 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -579,6 +579,19 @@ static int register_pcc_channel(int pcc_subspace_idx)
         return 0;
 }
 
+/**
+ * cpc_ffh_supported() - check if FFH reading supported
+ *
+ * Check if the architecture has support for functional fixed hardware
+ * read/write capability.
+ *
+ * Return: true for supported, false for not supported
+ */
+bool __weak cpc_ffh_supported(void)
+{
+        return false;
+}
+
 /*
  * An example CPC table looks like the following.
  *
@@ -728,9 +741,11 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
                                         cpc_ptr->cpc_regs[i-2].sys_mem_vaddr = addr;
                                 }
                         } else {
-                                /* Support only PCC and SYS MEM type regs */
-                                pr_debug("Unsupported register type: %d\n", gas_t->space_id);
-                                goto out_free;
+                                if (gas_t->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE || !cpc_ffh_supported()) {
+                                        /* Support only PCC ,SYS MEM and FFH type regs */
+                                        pr_debug("Unsupported register type: %d\n", gas_t->space_id);
+                                        goto out_free;
+                                }
                         }
 
                         cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_BUFFER;
@@ -819,13 +834,43 @@ void acpi_cppc_processor_exit(struct acpi_processor *pr)
 }
 EXPORT_SYMBOL_GPL(acpi_cppc_processor_exit);
 
+/**
+ * cpc_read_ffh() - Read FFH register
+ * @cpunum:     cpu number to read
+ * @reg:        cppc register information
+ * @val:        place holder for return value
+ *
+ * Read bit_width bits from a specified address and bit_offset
+ *
+ * Return: 0 for success and error code
+ */
+int __weak cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val)
+{
+        return -ENOTSUPP;
+}
+
+/**
+ * cpc_write_ffh() - Write FFH register
+ * @cpunum:     cpu number to write
+ * @reg:        cppc register information
+ * @val:        value to write
+ *
+ * Write value of bit_width bits to a specified address and bit_offset
+ *
+ * Return: 0 for success and error code
+ */
+int __weak cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
+{
+        return -ENOTSUPP;
+}
+
 /*
  * Since cpc_read and cpc_write are called while holding pcc_lock, it should be
  * as fast as possible. We have already mapped the PCC subspace during init, so
  * we can directly write to it.
  */
 
-static int cpc_read(struct cpc_register_resource *reg_res, u64 *val)
+static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
 {
         int ret_val = 0;
         void __iomem *vaddr = 0;
@@ -841,6 +886,8 @@ static int cpc_read(struct cpc_register_resource *reg_res, u64 *val)
                 vaddr = GET_PCC_VADDR(reg->address);
         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);
@@ -867,7 +914,7 @@ static int cpc_read(struct cpc_register_resource *reg_res, u64 *val)
         return ret_val;
 }
 
-static int cpc_write(struct cpc_register_resource *reg_res, u64 val)
+static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
 {
         int ret_val = 0;
         void __iomem *vaddr = 0;
@@ -877,6 +924,8 @@ static int cpc_write(struct cpc_register_resource *reg_res, u64 val)
                 vaddr = GET_PCC_VADDR(reg->address);
         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);
@@ -941,13 +990,13 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
                 }
         }
 
-        cpc_read(highest_reg, &high);
+        cpc_read(cpunum, highest_reg, &high);
         perf_caps->highest_perf = high;
 
-        cpc_read(lowest_reg, &low);
+        cpc_read(cpunum, lowest_reg, &low);
         perf_caps->lowest_perf = low;
 
-        cpc_read(nom_perf, &nom);
+        cpc_read(cpunum, nom_perf, &nom);
         perf_caps->nominal_perf = nom;
 
         if (!high || !low || !nom)
@@ -1004,9 +1053,9 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
                 }
         }
 
-        cpc_read(delivered_reg, &delivered);
-        cpc_read(reference_reg, &reference);
-        cpc_read(ref_perf_reg, &ref_perf);
+        cpc_read(cpunum, delivered_reg, &delivered);
+        cpc_read(cpunum, reference_reg, &reference);
+        cpc_read(cpunum, ref_perf_reg, &ref_perf);
 
         /*
          * Per spec, if ctr_wrap_time optional register is unsupported, then the
@@ -1015,7 +1064,7 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
          */
         ctr_wrap_time = (u64)(~((u64)0));
         if (CPC_SUPPORTED(ctr_wrap_reg))
-                cpc_read(ctr_wrap_reg, &ctr_wrap_time);
+                cpc_read(cpunum, ctr_wrap_reg, &ctr_wrap_time);
 
         if (!delivered || !reference || !ref_perf) {
                 ret = -EFAULT;
@@ -1082,7 +1131,7 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
          * Skip writing MIN/MAX until Linux knows how to come up with
          * useful values.
          */
-        cpc_write(desired_reg, perf_ctrls->desired_perf);
+        cpc_write(cpu, desired_reg, perf_ctrls->desired_perf);
 
         if (CPC_IN_PCC(desired_reg))
                 up_read(&pcc_data.pcc_lock);    /* END Phase-I */