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// SPDX-License-Identifier: GPL-2.0-only/* * CPPC (Collaborative Processor Performance Control) methods used by CPUfreq drivers. * * (C) Copyright 2014, 2015 Linaro Ltd. * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org> * * CPPC describes a few methods for controlling CPU performance using * information from a per CPU table called CPC. This table is described in * the ACPI v5.0+ specification. The table consists of a list of * registers which may be memory mapped or hardware registers and also may * include some static integer values. * * CPU performance is on an abstract continuous scale as against a discretized * P-state scale which is tied to CPU frequency only. In brief, the basic * operation involves: * * - OS makes a CPU performance request. (Can provide min and max bounds) * * - Platform (such as BMC) is free to optimize request within requested bounds *   depending on power/thermal budgets etc. * * - Platform conveys its decision back to OS * * The communication between OS and platform occurs through another medium * called (PCC) Platform Communication Channel. This is a generic mailbox like * mechanism which includes doorbell semantics to indicate register updates. * See drivers/mailbox/pcc.c for details on PCC. * * Finer details about the PCC and CPPC spec are available in the ACPI v5.1 and * above specifications. */ #define pr_fmt(fmt)	"ACPI CPPC: " fmt #include <linux/delay.h>#include <linux/iopoll.h>#include <linux/ktime.h>#include <linux/rwsem.h>#include <linux/wait.h>#include <linux/topology.h>#include <linux/dmi.h>#include <linux/units.h>#include <linux/unaligned.h> #include <acpi/cppc_acpi.h> struct cppc_pcc_data {	struct pcc_mbox_chan *pcc_channel;	bool pcc_channel_acquired;	unsigned int deadline_us;	unsigned int pcc_mpar, pcc_mrtt, pcc_nominal; 	bool pending_pcc_write_cmd;	/* Any pending/batched PCC write cmds? */	bool platform_owns_pcc;		/* Ownership of PCC subspace */	unsigned int pcc_write_cnt;	/* Running count of PCC write commands */ 	/*	 * Lock to provide controlled access to the PCC channel.	 *	 * For performance critical usecases(currently cppc_set_perf)	 *	We need to take read_lock and check if channel belongs to OSPM	 * before reading or writing to PCC subspace	 *	We need to take write_lock before transferring the channel	 * ownership to the platform via a Doorbell	 *	This allows us to batch a number of CPPC requests if they happen	 * to originate in about the same time	 *	 * For non-performance critical usecases(init)	 *	Take write_lock for all purposes which gives exclusive access	 */	struct rw_semaphore pcc_lock; 	/* Wait queue for CPUs whose requests were batched */	wait_queue_head_t pcc_write_wait_q;	ktime_t last_cmd_cmpl_time;	ktime_t last_mpar_reset;	int mpar_count;	int refcount;}; /* Array to represent the PCC channel per subspace ID */static struct cppc_pcc_data *pcc_data[MAX_PCC_SUBSPACES];/* The cpu_pcc_subspace_idx contains per CPU subspace ID */static DEFINE_PER_CPU(int, cpu_pcc_subspace_idx); /* * The cpc_desc structure contains the ACPI register details * as described in the per CPU _CPC tables. The details * include the type of register (e.g. PCC, System IO, FFH etc.) * and destination addresses which lets us READ/WRITE CPU performance * information using the appropriate I/O methods. */static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr); /* pcc mapped address + header size + offset within PCC subspace */#define GET_PCC_VADDR(offs, pcc_ss_id) (pcc_data[pcc_ss_id]->pcc_channel->shmem + \						0x8 + (offs)) /* Check if a CPC register is in PCC */#define CPC_IN_PCC(cpc) ((cpc)->type == ACPI_TYPE_BUFFER &&		\				(cpc)->cpc_entry.reg.space_id ==	\				ACPI_ADR_SPACE_PLATFORM_COMM) /* Check if a CPC register is in FFH */#define CPC_IN_FFH(cpc) ((cpc)->type == ACPI_TYPE_BUFFER &&		\				(cpc)->cpc_entry.reg.space_id ==	\				ACPI_ADR_SPACE_FIXED_HARDWARE) /* Check if a CPC register is in SystemMemory */#define CPC_IN_SYSTEM_MEMORY(cpc) ((cpc)->type == ACPI_TYPE_BUFFER &&	\				(cpc)->cpc_entry.reg.space_id ==	\				ACPI_ADR_SPACE_SYSTEM_MEMORY) /* Check if a CPC register is in SystemIo */#define CPC_IN_SYSTEM_IO(cpc) ((cpc)->type == ACPI_TYPE_BUFFER &&	\				(cpc)->cpc_entry.reg.space_id ==	\				ACPI_ADR_SPACE_SYSTEM_IO) /* Evaluates to True if reg is a NULL register descriptor */#define IS_NULL_REG(reg) ((reg)->space_id ==  ACPI_ADR_SPACE_SYSTEM_MEMORY && \				(reg)->address == 0 &&			\				(reg)->bit_width == 0 &&		\				(reg)->bit_offset == 0 &&		\				(reg)->access_width == 0) /* Evaluates to True if an optional cpc field is supported */#define CPC_SUPPORTED(cpc) ((cpc)->type == ACPI_TYPE_INTEGER ?		\				!!(cpc)->cpc_entry.int_value :		\				!IS_NULL_REG(&(cpc)->cpc_entry.reg)) /* * Each bit indicates the optionality of the register in per-cpu * cpc_regs[] with the corresponding index. 0 means mandatory and 1 * means optional. */#define REG_OPTIONAL (0x7FC7D0) /* * Use the index of the register in per-cpu cpc_regs[] to check if * it's an optional one. */#define IS_OPTIONAL_CPC_REG(reg_idx) (REG_OPTIONAL & (1U << (reg_idx))) /* * Arbitrary Retries in case the remote processor is slow to respond * to PCC commands. Keeping it high enough to cover emulators where * the processors run painfully slow. */#define NUM_RETRIES 500ULL #define OVER_16BTS_MASK ~0xFFFFULL #define define_one_cppc_ro(_name)		\static struct kobj_attribute _name =		\__ATTR(_name, 0444, show_##_name, NULL) #define to_cpc_desc(a) container_of(a, struct cpc_desc, kobj) #define show_cppc_data(access_fn, struct_name, member_name)		\	static ssize_t show_##member_name(struct kobject *kobj,		\				struct kobj_attribute *attr, char *buf)	\	{								\		struct cpc_desc *cpc_ptr = to_cpc_desc(kobj);		\		struct struct_name st_name = {0};			\		int ret;						\									\		ret = access_fn(cpc_ptr->cpu_id, &st_name);		\		if (ret)						\			return ret;					\									\		return sysfs_emit(buf, "%llu\n",		\				(u64)st_name.member_name);		\	}								\	define_one_cppc_ro(member_name) show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, highest_perf);show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_perf);show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_perf);show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, reference_perf);show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_nonlinear_perf);show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, guaranteed_perf);show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_freq);show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_freq); show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, wraparound_time); /* * PCC reuses the access_width field as the subspace id, so only decode access * size for non-PCC registers. Otherwise, use the bit_width. */#define GET_BIT_WIDTH(reg) (((reg)->access_width &&				\			     (reg)->space_id != ACPI_ADR_SPACE_PLATFORM_COMM) ? \			    (8 << ((reg)->access_width - 1)) : (reg)->bit_width) /* Shift and apply the mask for CPC reads/writes */#define MASK_VAL_READ(reg, val) (((val) >> (reg)->bit_offset) &				\					GENMASK(((reg)->bit_width) - 1, 0))#define MASK_VAL_WRITE(reg, prev_val, val)						\	((((val) & GENMASK(((reg)->bit_width) - 1, 0)) << (reg)->bit_offset) |		\	((prev_val) & ~(GENMASK(((reg)->bit_width) - 1, 0) << (reg)->bit_offset)))	\ static u64 cpc_sysmem_access_size(const struct cpc_register_resource *reg){	const struct cpc_reg *gas = &reg->cpc_entry.reg;	unsigned int width; 	if (gas->access_width > 4)		return 0; 	width = GET_BIT_WIDTH(gas); 	if (width != 8 && width != 16 && width != 32 && width != 64)		return 0; 	return width / 8;} static bool cpc_sysmem_access_units_overlap(const struct cpc_register_resource *a,					    const struct cpc_register_resource *b){	const struct cpc_reg *a_gas = &a->cpc_entry.reg;	const struct cpc_reg *b_gas = &b->cpc_entry.reg;	u64 a_size = cpc_sysmem_access_size(a);	u64 b_size = cpc_sysmem_access_size(b); 	/* Keep the conservative locking path for malformed access widths. */	if (!a_size || !b_size)		return true; 	if (a_gas->address < b_gas->address)		return b_gas->address - a_gas->address < a_size; 	return a_gas->address - b_gas->address < b_size;} static void cpc_mark_rmw_lock_users(struct cpc_desc *cpc_desc){	int i, j; 	for (i = 0; i < cpc_desc->num_entries - 2; i++) {		struct cpc_register_resource *a = &cpc_desc->cpc_regs[i];		struct cpc_reg *gas;		u64 access_size; 		if (!CPC_SUPPORTED(a) || !CPC_IN_SYSTEM_MEMORY(a))			continue; 		gas = &a->cpc_entry.reg;		access_size = cpc_sysmem_access_size(a);		if (gas->bit_offset || !access_size ||		    gas->bit_width != access_size * 8)			a->cpc_entry.use_rmw_lock = true; 		for (j = i + 1; j < cpc_desc->num_entries - 2; j++) {			struct cpc_register_resource *b = &cpc_desc->cpc_regs[j]; 			if (!CPC_SUPPORTED(b) || !CPC_IN_SYSTEM_MEMORY(b))				continue;			if (!cpc_sysmem_access_units_overlap(a, b))				continue; 			a->cpc_entry.use_rmw_lock = true;			b->cpc_entry.use_rmw_lock = true;		}	}} static ssize_t show_feedback_ctrs(struct kobject *kobj,		struct kobj_attribute *attr, char *buf){	struct cpc_desc *cpc_ptr = to_cpc_desc(kobj);	struct cppc_perf_fb_ctrs fb_ctrs = {0};	int ret; 	ret = cppc_get_perf_ctrs(cpc_ptr->cpu_id, &fb_ctrs);	if (ret)		return ret; 	return sysfs_emit(buf, "ref:%llu del:%llu\n",			fb_ctrs.reference, fb_ctrs.delivered);}define_one_cppc_ro(feedback_ctrs); static struct attribute *cppc_attrs[] = {	&feedback_ctrs.attr,	&reference_perf.attr,	&wraparound_time.attr,	&highest_perf.attr,	&lowest_perf.attr,	&lowest_nonlinear_perf.attr,	&guaranteed_perf.attr,	&nominal_perf.attr,	&nominal_freq.attr,	&lowest_freq.attr,	NULL};ATTRIBUTE_GROUPS(cppc); static const struct kobj_type cppc_ktype = {	.sysfs_ops = &kobj_sysfs_ops,	.default_groups = cppc_groups,}; static int check_pcc_chan(int pcc_ss_id, bool chk_err_bit){	int ret, status;	struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];	struct acpi_pcct_shared_memory __iomem *generic_comm_base =					pcc_ss_data->pcc_channel->shmem; 	if (!pcc_ss_data->platform_owns_pcc)		return 0; 	/*	 * Poll PCC status register every 3us(delay_us) for maximum of	 * deadline_us(timeout_us) until PCC command complete bit is set(cond)	 */	ret = readw_relaxed_poll_timeout(&generic_comm_base->status, status,					status & PCC_CMD_COMPLETE_MASK, 3,					pcc_ss_data->deadline_us); 	if (likely(!ret)) {		pcc_ss_data->platform_owns_pcc = false;		if (chk_err_bit && (status & PCC_ERROR_MASK))			ret = -EIO;	} 	if (unlikely(ret))		pr_err("PCC check channel failed for ss: %d. ret=%d\n",		       pcc_ss_id, ret); 	return ret;} /* * This function transfers the ownership of the PCC to the platform * So it must be called while holding write_lock(pcc_lock) */static int send_pcc_cmd(int pcc_ss_id, u16 cmd){	int ret = -EIO, i;	struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];	struct acpi_pcct_shared_memory __iomem *generic_comm_base =					pcc_ss_data->pcc_channel->shmem;	unsigned int time_delta; 	/*	 * For CMD_WRITE we know for a fact the caller should have checked	 * the channel before writing to PCC space	 */	if (cmd == CMD_READ) {		/*		 * If there are pending cpc_writes, then we stole the channel		 * before write completion, so first send a WRITE command to		 * platform		 */		if (pcc_ss_data->pending_pcc_write_cmd)			send_pcc_cmd(pcc_ss_id, CMD_WRITE); 		ret = check_pcc_chan(pcc_ss_id, false);		if (ret)			goto end;	} else /* CMD_WRITE */		pcc_ss_data->pending_pcc_write_cmd = FALSE; 	/*	 * Handle the Minimum Request Turnaround Time(MRTT)	 * "The minimum amount of time that OSPM must wait after the completion	 * of a command before issuing the next command, in microseconds"	 */	if (pcc_ss_data->pcc_mrtt) {		time_delta = ktime_us_delta(ktime_get(),					    pcc_ss_data->last_cmd_cmpl_time);		if (pcc_ss_data->pcc_mrtt > time_delta)			udelay(pcc_ss_data->pcc_mrtt - time_delta);	} 	/*	 * Handle the non-zero Maximum Periodic Access Rate(MPAR)	 * "The maximum number of periodic requests that the subspace channel can	 * support, reported in commands per minute. 0 indicates no limitation."	 *	 * This parameter should be ideally zero or large enough so that it can	 * handle maximum number of requests that all the cores in the system can	 * collectively generate. If it is not, we will follow the spec and just	 * not send the request to the platform after hitting the MPAR limit in	 * any 60s window	 */	if (pcc_ss_data->pcc_mpar) {		if (pcc_ss_data->mpar_count == 0) {			time_delta = ktime_ms_delta(ktime_get(),						    pcc_ss_data->last_mpar_reset);			if ((time_delta < 60 * MSEC_PER_SEC) && pcc_ss_data->last_mpar_reset) {				pr_debug("PCC cmd for subspace %d not sent due to MPAR limit",					 pcc_ss_id);				ret = -EIO;				goto end;			}			pcc_ss_data->last_mpar_reset = ktime_get();			pcc_ss_data->mpar_count = pcc_ss_data->pcc_mpar;		}		pcc_ss_data->mpar_count--;	} 	/* Write to the shared comm region. */	writew_relaxed(cmd, &generic_comm_base->command); 	/* Flip CMD COMPLETE bit */	writew_relaxed(0, &generic_comm_base->status); 	pcc_ss_data->platform_owns_pcc = true; 	/* Ring doorbell */	ret = mbox_send_message(pcc_ss_data->pcc_channel->mchan, &cmd);	if (ret < 0) {		pr_err("Err sending PCC mbox message. ss: %d cmd:%d, ret:%d\n",		       pcc_ss_id, cmd, ret);		goto end;	} 	/* wait for completion and check for PCC error bit */	ret = check_pcc_chan(pcc_ss_id, true); 	if (pcc_ss_data->pcc_mrtt)		pcc_ss_data->last_cmd_cmpl_time = ktime_get(); 	if (pcc_ss_data->pcc_channel->mchan->mbox->txdone_irq)		mbox_chan_txdone(pcc_ss_data->pcc_channel->mchan, ret);	else		mbox_client_txdone(pcc_ss_data->pcc_channel->mchan, ret); end:	if (cmd == CMD_WRITE) {		if (unlikely(ret)) {			for_each_possible_cpu(i) {				struct cpc_desc *desc = per_cpu(cpc_desc_ptr, i); 				if (!desc)					continue; 				if (desc->write_cmd_id == pcc_ss_data->pcc_write_cnt)					desc->write_cmd_status = ret;			}		}		pcc_ss_data->pcc_write_cnt++;		wake_up_all(&pcc_ss_data->pcc_write_wait_q);	} 	return ret;} static void cppc_chan_tx_done(struct mbox_client *cl, void *msg, int ret){	if (ret < 0)		pr_debug("TX did not complete: CMD sent:%x, ret:%d\n",				*(u16 *)msg, ret);	else		pr_debug("TX completed. CMD sent:%x, ret:%d\n",				*(u16 *)msg, ret);} static struct mbox_client cppc_mbox_cl = {	.tx_done = cppc_chan_tx_done,	.knows_txdone = true,}; static int acpi_get_psd(struct cpc_desc *cpc_ptr, acpi_handle handle){	int result = -EFAULT;	acpi_status status = AE_OK;	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};	struct acpi_buffer format = {sizeof("NNNNN"), "NNNNN"};	struct acpi_buffer state = {0, NULL};	union acpi_object  *psd = NULL;	struct acpi_psd_package *pdomain; 	status = acpi_evaluate_object_typed(handle, "_PSD", NULL,					    &buffer, ACPI_TYPE_PACKAGE);	if (status == AE_NOT_FOUND)	/* _PSD is optional */		return 0;	if (ACPI_FAILURE(status))		return -ENODEV; 	psd = buffer.pointer;	if (!psd || psd->package.count != 1) {		pr_debug("Invalid _PSD data\n");		goto end;	} 	pdomain = &(cpc_ptr->domain_info); 	state.length = sizeof(struct acpi_psd_package);	state.pointer = pdomain; 	status = acpi_extract_package(&(psd->package.elements[0]),		&format, &state);	if (ACPI_FAILURE(status)) {		pr_debug("Invalid _PSD data for CPU:%d\n", cpc_ptr->cpu_id);		goto end;

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