mpam.c

  1// SPDX-License-Identifier: GPL-2.0
  2// Copyright (C) 2025 Arm Ltd.
  3
  4/* Parse the MPAM ACPI table feeding the discovered nodes into the driver */
  5
  6#define pr_fmt(fmt) "ACPI MPAM: " fmt
  7
  8#include <linux/acpi.h>
  9#include <linux/arm_mpam.h>
 10#include <linux/bits.h>
 11#include <linux/cpu.h>
 12#include <linux/cpumask.h>
 13#include <linux/platform_device.h>
 14
 15#include <acpi/processor.h>
 16
 17/*
 18 * Flags for acpi_table_mpam_msc.*_interrupt_flags.
 19 * See 2.1.1 Interrupt Flags, Table 5, of DEN0065B_MPAM_ACPI_3.0-bet.
 20 */
 21#define ACPI_MPAM_MSC_IRQ_MODE                              BIT(0)
 22#define ACPI_MPAM_MSC_IRQ_TYPE_MASK                         GENMASK(2, 1)
 23#define ACPI_MPAM_MSC_IRQ_TYPE_WIRED                        0
 24#define ACPI_MPAM_MSC_IRQ_AFFINITY_TYPE_MASK                BIT(3)
 25#define ACPI_MPAM_MSC_IRQ_AFFINITY_TYPE_PROCESSOR           0
 26#define ACPI_MPAM_MSC_IRQ_AFFINITY_TYPE_PROCESSOR_CONTAINER 1
 27#define ACPI_MPAM_MSC_IRQ_AFFINITY_VALID                    BIT(4)
 28
 29/*
 30 * Encodings for the MSC node body interface type field.
 31 * See 2.1 MPAM MSC node, Table 4 of DEN0065B_MPAM_ACPI_3.0-bet.
 32 */
 33#define ACPI_MPAM_MSC_IFACE_MMIO   0x00
 34#define ACPI_MPAM_MSC_IFACE_PCC    0x0a
 35
 36static bool _is_ppi_partition(u32 flags)
 37{
 38	u32 aff_type, is_ppi;
 39	bool ret;
 40
 41	is_ppi = FIELD_GET(ACPI_MPAM_MSC_IRQ_AFFINITY_VALID, flags);
 42	if (!is_ppi)
 43		return false;
 44
 45	aff_type = FIELD_GET(ACPI_MPAM_MSC_IRQ_AFFINITY_TYPE_MASK, flags);
 46	ret = (aff_type == ACPI_MPAM_MSC_IRQ_AFFINITY_TYPE_PROCESSOR_CONTAINER);
 47	if (ret)
 48		pr_err_once("Partitioned interrupts not supported\n");
 49
 50	return ret;
 51}
 52
 53static int acpi_mpam_register_irq(struct platform_device *pdev,
 54				  u32 intid, u32 flags)
 55{
 56	int irq;
 57	u32 int_type;
 58	int trigger;
 59
 60	if (!intid)
 61		return -EINVAL;
 62
 63	if (_is_ppi_partition(flags))
 64		return -EINVAL;
 65
 66	trigger = FIELD_GET(ACPI_MPAM_MSC_IRQ_MODE, flags);
 67	int_type = FIELD_GET(ACPI_MPAM_MSC_IRQ_TYPE_MASK, flags);
 68	if (int_type != ACPI_MPAM_MSC_IRQ_TYPE_WIRED)
 69		return -EINVAL;
 70
 71	irq = acpi_register_gsi(&pdev->dev, intid, trigger, ACPI_ACTIVE_HIGH);
 72	if (irq < 0)
 73		pr_err_once("Failed to register interrupt 0x%x with ACPI\n", intid);
 74
 75	return irq;
 76}
 77
 78static void acpi_mpam_parse_irqs(struct platform_device *pdev,
 79				 struct acpi_mpam_msc_node *tbl_msc,
 80				 struct resource *res, int *res_idx)
 81{
 82	u32 flags, intid;
 83	int irq;
 84
 85	intid = tbl_msc->overflow_interrupt;
 86	flags = tbl_msc->overflow_interrupt_flags;
 87	irq = acpi_mpam_register_irq(pdev, intid, flags);
 88	if (irq > 0)
 89		res[(*res_idx)++] = DEFINE_RES_IRQ_NAMED(irq, "overflow");
 90
 91	intid = tbl_msc->error_interrupt;
 92	flags = tbl_msc->error_interrupt_flags;
 93	irq = acpi_mpam_register_irq(pdev, intid, flags);
 94	if (irq > 0)
 95		res[(*res_idx)++] = DEFINE_RES_IRQ_NAMED(irq, "error");
 96}
 97
 98static int acpi_mpam_parse_resource(struct mpam_msc *msc,
 99				    struct acpi_mpam_resource_node *res)
100{
101	int level, nid;
102	u32 cache_id;
103
104	switch (res->locator_type) {
105	case ACPI_MPAM_LOCATION_TYPE_PROCESSOR_CACHE:
106		cache_id = res->locator.cache_locator.cache_reference;
107		level = find_acpi_cache_level_from_id(cache_id);
108		if (level <= 0) {
109			pr_err_once("Bad level (%d) for cache with id %u\n", level, cache_id);
110			return -EINVAL;
111		}
112		return mpam_ris_create(msc, res->ris_index, MPAM_CLASS_CACHE,
113				       level, cache_id);
114	case ACPI_MPAM_LOCATION_TYPE_MEMORY:
115		nid = pxm_to_node(res->locator.memory_locator.proximity_domain);
116		if (nid == NUMA_NO_NODE) {
117			pr_debug("Bad proximity domain %lld, using node 0 instead\n",
118				 res->locator.memory_locator.proximity_domain);
119			nid = 0;
120		}
121		return mpam_ris_create(msc, res->ris_index, MPAM_CLASS_MEMORY,
122				       MPAM_CLASS_ID_DEFAULT, nid);
123	default:
124		/* These get discovered later and are treated as unknown */
125		return 0;
126	}
127}
128
129int acpi_mpam_parse_resources(struct mpam_msc *msc,
130			      struct acpi_mpam_msc_node *tbl_msc)
131{
132	int i, err;
133	char *ptr, *table_end;
134	struct acpi_mpam_resource_node *resource;
135
136	table_end = (char *)tbl_msc + tbl_msc->length;
137	ptr = (char *)(tbl_msc + 1);
138	for (i = 0; i < tbl_msc->num_resource_nodes; i++) {
139		u64 max_deps, remaining_table;
140
141		if (ptr + sizeof(*resource) > table_end)
142			return -EINVAL;
143
144		resource = (struct acpi_mpam_resource_node *)ptr;
145
146		remaining_table = table_end - ptr;
147		max_deps = remaining_table / sizeof(struct acpi_mpam_func_deps);
148		if (resource->num_functional_deps > max_deps) {
149			pr_debug("MSC has impossible number of functional dependencies\n");
150			return -EINVAL;
151		}
152
153		err = acpi_mpam_parse_resource(msc, resource);
154		if (err)
155			return err;
156
157		ptr += sizeof(*resource);
158		ptr += resource->num_functional_deps * sizeof(struct acpi_mpam_func_deps);
159	}
160
161	return 0;
162}
163
164/*
165 * Creates the device power management link and returns true if the
166 * acpi id is valid and usable for cpu affinity.  This is the case
167 * when the linked device is a processor or a processor container.
168 */
169static bool __init parse_msc_pm_link(struct acpi_mpam_msc_node *tbl_msc,
170				     struct platform_device *pdev,
171				     u32 *acpi_id)
172{
173	char hid[sizeof(tbl_msc->hardware_id_linked_device) + 1] = { 0 };
174	bool acpi_id_valid = false;
175	struct acpi_device *buddy;
176	char uid[11];
177	int len;
178
179	memcpy(hid, &tbl_msc->hardware_id_linked_device,
180	       sizeof(tbl_msc->hardware_id_linked_device));
181
182	if (!strcmp(hid, ACPI_PROCESSOR_CONTAINER_HID)) {
183		*acpi_id = tbl_msc->instance_id_linked_device;
184		acpi_id_valid = true;
185	}
186
187	len = snprintf(uid, sizeof(uid), "%u",
188		       tbl_msc->instance_id_linked_device);
189	if (len >= sizeof(uid)) {
190		pr_debug("Failed to convert uid of device for power management.");
191		return acpi_id_valid;
192	}
193
194	buddy = acpi_dev_get_first_match_dev(hid, uid, -1);
195	if (buddy) {
196		device_link_add(&pdev->dev, &buddy->dev, DL_FLAG_STATELESS);
197		acpi_dev_put(buddy);
198	}
199
200	return acpi_id_valid;
201}
202
203static int decode_interface_type(struct acpi_mpam_msc_node *tbl_msc,
204				 enum mpam_msc_iface *iface)
205{
206	switch (tbl_msc->interface_type) {
207	case ACPI_MPAM_MSC_IFACE_MMIO:
208		*iface = MPAM_IFACE_MMIO;
209		return 0;
210	case ACPI_MPAM_MSC_IFACE_PCC:
211		*iface = MPAM_IFACE_PCC;
212		return 0;
213	default:
214		return -EINVAL;
215	}
216}
217
218static struct platform_device * __init acpi_mpam_parse_msc(struct acpi_mpam_msc_node *tbl_msc)
219{
220	struct platform_device *pdev __free(platform_device_put) =
221		platform_device_alloc("mpam_msc", tbl_msc->identifier);
222	int next_res = 0, next_prop = 0, err;
223	/* pcc, nrdy, affinity and a sentinel */
224	struct property_entry props[4] = { 0 };
225	/* mmio, 2xirq, no sentinel. */
226	struct resource res[3] = { 0 };
227	struct acpi_device *companion;
228	enum mpam_msc_iface iface;
229	char uid[16];
230	u32 acpi_id;
231
232	if (!pdev)
233		return ERR_PTR(-ENOMEM);
234
235	/* Some power management is described in the namespace: */
236	err = snprintf(uid, sizeof(uid), "%u", tbl_msc->identifier);
237	if (err > 0 && err < sizeof(uid)) {
238		companion = acpi_dev_get_first_match_dev("ARMHAA5C", uid, -1);
239		if (companion) {
240			ACPI_COMPANION_SET(&pdev->dev, companion);
241			acpi_dev_put(companion);
242		} else {
243			pr_debug("MSC.%u: missing namespace entry\n", tbl_msc->identifier);
244		}
245	}
246
247	if (decode_interface_type(tbl_msc, &iface)) {
248		pr_debug("MSC.%u: unknown interface type\n", tbl_msc->identifier);
249		return ERR_PTR(-EINVAL);
250	}
251
252	if (iface == MPAM_IFACE_MMIO) {
253		res[next_res++] = DEFINE_RES_MEM_NAMED(tbl_msc->base_address,
254						       tbl_msc->mmio_size,
255						       "MPAM:MSC");
256	} else if (iface == MPAM_IFACE_PCC) {
257		props[next_prop++] = PROPERTY_ENTRY_U32("pcc-channel",
258							tbl_msc->base_address);
259	}
260
261	acpi_mpam_parse_irqs(pdev, tbl_msc, res, &next_res);
262
263	WARN_ON_ONCE(next_res > ARRAY_SIZE(res));
264	err = platform_device_add_resources(pdev, res, next_res);
265	if (err)
266		return ERR_PTR(err);
267
268	props[next_prop++] = PROPERTY_ENTRY_U32("arm,not-ready-us",
269						tbl_msc->max_nrdy_usec);
270
271	/*
272	 * The MSC's CPU affinity is described via its linked power
273	 * management device, but only if it points at a Processor or
274	 * Processor Container.
275	 */
276	if (parse_msc_pm_link(tbl_msc, pdev, &acpi_id))
277		props[next_prop++] = PROPERTY_ENTRY_U32("cpu_affinity", acpi_id);
278
279	WARN_ON_ONCE(next_prop > ARRAY_SIZE(props) - 1);
280	err = device_create_managed_software_node(&pdev->dev, props, NULL);
281	if (err)
282		return ERR_PTR(err);
283
284	/*
285	 * Stash the table entry for acpi_mpam_parse_resources() to discover
286	 * what this MSC controls.
287	 */
288	err = platform_device_add_data(pdev, tbl_msc, tbl_msc->length);
289	if (err)
290		return ERR_PTR(err);
291
292	err = platform_device_add(pdev);
293	if (err)
294		return ERR_PTR(err);
295
296	return_ptr(pdev);
297}
298
299static int __init acpi_mpam_parse(void)
300{
301	char *table_end, *table_offset;
302	struct acpi_mpam_msc_node *tbl_msc;
303	struct platform_device *pdev;
304
305	if (acpi_disabled || !system_supports_mpam())
306		return 0;
307
308	struct acpi_table_header *table __free(acpi_put_table) =
309		acpi_get_table_pointer(ACPI_SIG_MPAM, 0);
310
311	if (IS_ERR(table))
312		return 0;
313
314	if (table->revision < 1) {
315		pr_debug("MPAM ACPI table revision %d not supported\n", table->revision);
316		return 0;
317	}
318
319	table_offset = (char *)(table + 1);
320	table_end = (char *)table + table->length;
321
322	while (table_offset < table_end) {
323		tbl_msc = (struct acpi_mpam_msc_node *)table_offset;
324		if (table_offset + sizeof(*tbl_msc) > table_end ||
325		    table_offset + tbl_msc->length > table_end) {
326			pr_err("MSC entry overlaps end of ACPI table\n");
327			return -EINVAL;
328		}
329		table_offset += tbl_msc->length;
330
331		/*
332		 * If any of the reserved fields are set, make no attempt to
333		 * parse the MSC structure. This MSC will still be counted by
334		 * acpi_mpam_count_msc(), meaning the MPAM driver can't probe
335		 * against all MSC, and will never be enabled. There is no way
336		 * to enable it safely, because we cannot determine safe
337		 * system-wide partid and pmg ranges in this situation.
338		 */
339		if (tbl_msc->reserved || tbl_msc->reserved1 || tbl_msc->reserved2) {
340			pr_err_once("Unrecognised MSC, MPAM not usable\n");
341			pr_debug("MSC.%u: reserved field set\n", tbl_msc->identifier);
342			continue;
343		}
344
345		if (!tbl_msc->mmio_size) {
346			pr_debug("MSC.%u: marked as disabled\n", tbl_msc->identifier);
347			continue;
348		}
349
350		pdev = acpi_mpam_parse_msc(tbl_msc);
351		if (IS_ERR(pdev))
352			return PTR_ERR(pdev);
353	}
354
355	return 0;
356}
357
358/**
359 * acpi_mpam_count_msc() - Count the number of MSC described by firmware.
360 *
361 * Returns the number of MSCs, or zero for an error.
362 *
363 * This can be called before or in parallel with acpi_mpam_parse().
364 */
365int acpi_mpam_count_msc(void)
366{
367	char *table_end, *table_offset;
368	struct acpi_mpam_msc_node *tbl_msc;
369	int count = 0;
370
371	if (acpi_disabled || !system_supports_mpam())
372		return 0;
373
374	struct acpi_table_header *table __free(acpi_put_table) =
375		acpi_get_table_pointer(ACPI_SIG_MPAM, 0);
376
377	if (IS_ERR(table))
378		return 0;
379
380	if (table->revision < 1)
381		return 0;
382
383	table_offset = (char *)(table + 1);
384	table_end = (char *)table + table->length;
385
386	while (table_offset < table_end) {
387		tbl_msc = (struct acpi_mpam_msc_node *)table_offset;
388
389		if (table_offset + sizeof(*tbl_msc) > table_end)
390			return -EINVAL;
391		if (tbl_msc->length < sizeof(*tbl_msc))
392			return -EINVAL;
393		if (tbl_msc->length > table_end - table_offset)
394			return -EINVAL;
395		table_offset += tbl_msc->length;
396
397		if (!tbl_msc->mmio_size)
398			continue;
399
400		count++;
401	}
402
403	return count;
404}
405
406/*
407 * Call after ACPI devices have been created, which happens behind acpi_scan_init()
408 * called from subsys_initcall(). PCC requires the mailbox driver, which is
409 * initialised from postcore_initcall().
410 */
411subsys_initcall_sync(acpi_mpam_parse);