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Commit 5bbb86aa authored by Ashwin Chaugule's avatar Ashwin Chaugule Committed by Rafael J. Wysocki
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ACPI / CPPC: restructure read/writes for efficient sys mapped reg ops 



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.

Signed-off-by: default avatarAshwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: default avatarPrashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent aca314ef

drivers/acpi/cppc_acpi.c

+71 −37
Original line number Diff line number Diff line
@@ -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);
@@ -651,13 +671,25 @@ 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) {

		case 8:
@@ -677,18 +709,23 @@ static int cpc_read(struct cpc_reg *reg, u64 *val) 
					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) {

		case 8:
@@ -709,9 +746,7 @@ static int cpc_write(struct cpc_reg *reg, u64 val) 
			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)
@@ -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);

include/acpi/cppc_acpi.h

+1 −0
Original line number Diff line number Diff line
@@ -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;