[PATCH V2 1/5] ACPI/CPPC: restructure read/writes for efficient sys mapped reg ops

Prashanth Prakash
2016-07-26T19:46:01Z

From: Ashwin Chaugule <ashwin.chaugule@linaro.org>

For cases where sys mapped CPC registers need to be accessed
frequently, it helps immensly to pre-map them rather than map
and unmap for each operation. e.g. case where feedback counters
are sys mem map registers.

Restructure cpc_read/write and the cpc_regs structure to allow
pre-mapping the system addresses and unmap them when the CPU exits.

Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
---
drivers/acpi/cppc_acpi.c | 108 +++++++++++++++++++++++++++++++----------------
include/acpi/cppc_acpi.h | 1 +
2 files changed, 72 insertions(+), 37 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 2e98173..fea58e2 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -62,7 +62,6 @@ static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr);
/* This layer handles all the PCC specifics for CPPC. */
static struct mbox_chan *pcc_channel;
static void __iomem *pcc_comm_addr;
-static u64 comm_base_addr;
static int pcc_subspace_idx = -1;
static bool pcc_channel_acquired;
static ktime_t deadline;
@@ -394,7 +393,6 @@ EXPORT_SYMBOL_GPL(acpi_get_psd_map);
static int register_pcc_channel(int pcc_subspace_idx)
{
struct acpi_pcct_hw_reduced *cppc_ss;
- unsigned int len;
u64 usecs_lat;

if (pcc_subspace_idx >= 0) {
@@ -419,12 +417,6 @@ static int register_pcc_channel(int pcc_subspace_idx)
return -ENODEV;
}

- /*
- * This is the shared communication region
- * for the OS and Platform to communicate over.
- */
- comm_base_addr = cppc_ss->base_address;
- len = cppc_ss->length;

/*
* cppc_ss->latency is just a Nominal value. In reality
@@ -436,7 +428,7 @@ static int register_pcc_channel(int pcc_subspace_idx)
pcc_mrtt = cppc_ss->min_turnaround_time;
pcc_mpar = cppc_ss->max_access_rate;

- pcc_comm_addr = acpi_os_ioremap(comm_base_addr, len);
+ pcc_comm_addr = acpi_os_ioremap(cppc_ss->base_address, cppc_ss->length);
if (!pcc_comm_addr) {
pr_err("Failed to ioremap PCC comm region mem\n");
return -ENOMEM;
@@ -545,6 +537,8 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
goto out_free;
}

+ cpc_ptr->num_entries = num_ent;
+
/* Second entry should be revision. */
cpc_obj = &out_obj->package.elements[1];
if (cpc_obj->type == ACPI_TYPE_INTEGER) {
@@ -585,7 +579,16 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
pr_debug("Mismatched PCC ids.\n");
goto out_free;
}
- } else if (gas_t->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+ } else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+ if (gas_t->address) {
+ void __iomem *addr;
+
+ addr = ioremap(gas_t->address, gas_t->bit_width/8);
+ if (!addr)
+ goto out_free;
+ 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;
@@ -623,6 +626,13 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
return 0;

out_free:
+ /* Free all the mapped sys mem areas for this CPU */
+ for (i = 2; i < cpc_ptr->num_entries; i++) {
+ void __iomem *addr = cpc_ptr->cpc_regs[i-2].sys_mem_vaddr;
+
+ if (addr)
+ iounmap(addr);
+ }
kfree(cpc_ptr);

out_buf_free:
@@ -640,7 +650,17 @@ EXPORT_SYMBOL_GPL(acpi_cppc_processor_probe);
void acpi_cppc_processor_exit(struct acpi_processor *pr)
{
struct cpc_desc *cpc_ptr;
+ unsigned int i;
+ void __iomem *addr;
cpc_ptr = per_cpu(cpc_desc_ptr, pr->id);
+
+ /* Free all the mapped sys mem areas for this CPU */
+ for (i = 2; i < cpc_ptr->num_entries; i++) {
+ addr = cpc_ptr->cpc_regs[i-2].sys_mem_vaddr;
+ if (addr)
+ iounmap(addr);
+ }
+
kfree(cpc_ptr);
}
EXPORT_SYMBOL_GPL(acpi_cppc_processor_exit);
@@ -651,15 +671,27 @@ EXPORT_SYMBOL_GPL(acpi_cppc_processor_exit);
* we can directly write to it.
*/

-static int cpc_read(struct cpc_reg *reg, u64 *val)
+static int cpc_read(struct cpc_register_resource *reg_res, u64 *val)
{
int ret_val = 0;
+ void __iomem *vaddr = 0;
+ struct cpc_reg *reg = &reg_res->cpc_entry.reg;
+
+ if (reg_res->type == ACPI_TYPE_INTEGER) {
+ *val = reg_res->cpc_entry.int_value;
+ return ret_val;
+ }

*val = 0;
- if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
- void __iomem *vaddr = GET_PCC_VADDR(reg->address);
+ if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM)
+ vaddr = GET_PCC_VADDR(reg->address);
+ else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+ vaddr = reg_res->sys_mem_vaddr;
+ else
+ return acpi_os_read_memory((acpi_physical_address)reg->address,
+ val, reg->bit_width);

- switch (reg->bit_width) {
+ switch (reg->bit_width) {
case 8:
*val = readb_relaxed(vaddr);
break;
@@ -674,23 +706,28 @@ static int cpc_read(struct cpc_reg *reg, u64 *val)
break;
default:
pr_debug("Error: Cannot read %u bit width from PCC\n",
- reg->bit_width);
+ reg->bit_width);
ret_val = -EFAULT;
- }
- } else
- ret_val = acpi_os_read_memory((acpi_physical_address)reg->address,
- val, reg->bit_width);
+ }
+
return ret_val;
}

-static int cpc_write(struct cpc_reg *reg, u64 val)
+static int cpc_write(struct cpc_register_resource *reg_res, u64 val)
{
int ret_val = 0;
+ void __iomem *vaddr = 0;
+ struct cpc_reg *reg = &reg_res->cpc_entry.reg;

- if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
- void __iomem *vaddr = GET_PCC_VADDR(reg->address);
+ if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM)
+ vaddr = GET_PCC_VADDR(reg->address);
+ else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+ vaddr = reg_res->sys_mem_vaddr;
+ else
+ return acpi_os_write_memory((acpi_physical_address)reg->address,
+ val, reg->bit_width);

- switch (reg->bit_width) {
+ switch (reg->bit_width) {
case 8:
writeb_relaxed(val, vaddr);
break;
@@ -705,13 +742,11 @@ static int cpc_write(struct cpc_reg *reg, u64 val)
break;
default:
pr_debug("Error: Cannot write %u bit width to PCC\n",
- reg->bit_width);
+ reg->bit_width);
ret_val = -EFAULT;
break;
- }
- } else
- ret_val = acpi_os_write_memory((acpi_physical_address)reg->address,
- val, reg->bit_width);
+ }
+
return ret_val;
}

@@ -754,16 +789,16 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
}
}

- cpc_read(&highest_reg->cpc_entry.reg, &high);
+ cpc_read(highest_reg, &high);
perf_caps->highest_perf = high;

- cpc_read(&lowest_reg->cpc_entry.reg, &low);
+ cpc_read(lowest_reg, &low);
perf_caps->lowest_perf = low;

- cpc_read(&ref_perf->cpc_entry.reg, &ref);
+ cpc_read(ref_perf, &ref);
perf_caps->reference_perf = ref;

- cpc_read(&nom_perf->cpc_entry.reg, &nom);
+ cpc_read(nom_perf, &nom);
perf_caps->nominal_perf = nom;

if (!ref)
@@ -804,7 +839,7 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)

/* Are any of the regs PCC ?*/
if ((delivered_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) ||
- (reference_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM)) {
+ (reference_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM)) {
/* Ring doorbell once to update PCC subspace */
if (send_pcc_cmd(CMD_READ) < 0) {
ret = -EIO;
@@ -812,8 +847,8 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
}
}

- cpc_read(&delivered_reg->cpc_entry.reg, &delivered);
- cpc_read(&reference_reg->cpc_entry.reg, &reference);
+ cpc_read(delivered_reg, &delivered);
+ cpc_read(reference_reg, &reference);

if (!delivered || !reference) {
ret = -EFAULT;
@@ -868,7 +903,7 @@ 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->cpc_entry.reg, perf_ctrls->desired_perf);
+ cpc_write(desired_reg, perf_ctrls->desired_perf);

/* Is this a PCC reg ?*/
if (desired_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
@@ -878,7 +913,6 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
}
busy_channel:
spin_unlock(&pcc_lock);
-
return ret;
}
EXPORT_SYMBOL_GPL(cppc_set_perf);
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index 284965c..36ff5c6 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -49,6 +49,7 @@ struct cpc_reg {
*/
struct cpc_register_resource {
acpi_object_type type;
+ u64 __iomem *sys_mem_vaddr;
union {
struct cpc_reg reg;
u64 int_value;
--
Qualcomm Datacenter Technologies on behalf of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.