11dc65580SPeng Fan // SPDX-License-Identifier: GPL-2.0
21dc65580SPeng Fan /*
31dc65580SPeng Fan * System Control and Management Interface (SCMI) Message SMC/HVC
41dc65580SPeng Fan * Transport driver
51dc65580SPeng Fan *
61dc65580SPeng Fan * Copyright 2020 NXP
71dc65580SPeng Fan */
81dc65580SPeng Fan
91dc65580SPeng Fan #include <linux/arm-smccc.h>
100bfdca8aSCristian Marussi #include <linux/atomic.h>
111dc65580SPeng Fan #include <linux/device.h>
121dc65580SPeng Fan #include <linux/err.h>
13dd820ee2SJim Quinlan #include <linux/interrupt.h>
141dc65580SPeng Fan #include <linux/mutex.h>
151dc65580SPeng Fan #include <linux/of.h>
161dc65580SPeng Fan #include <linux/of_address.h>
17dd820ee2SJim Quinlan #include <linux/of_irq.h>
18da405477SNikunj Kela #include <linux/limits.h>
190bfdca8aSCristian Marussi #include <linux/processor.h>
201dc65580SPeng Fan #include <linux/slab.h>
211dc65580SPeng Fan
221dc65580SPeng Fan #include "common.h"
231dc65580SPeng Fan
245f2ea10aSNikunj Kela /*
255f2ea10aSNikunj Kela * The shmem address is split into 4K page and offset.
265f2ea10aSNikunj Kela * This is to make sure the parameters fit in 32bit arguments of the
275f2ea10aSNikunj Kela * smc/hvc call to keep it uniform across smc32/smc64 conventions.
285f2ea10aSNikunj Kela * This however limits the shmem address to 44 bit.
295f2ea10aSNikunj Kela *
305f2ea10aSNikunj Kela * These optional parameters can be used to distinguish among multiple
315f2ea10aSNikunj Kela * scmi instances that are using the same smc-id.
325f2ea10aSNikunj Kela * The page parameter is passed in r1/x1/w1 register and the offset parameter
335f2ea10aSNikunj Kela * is passed in r2/x2/w2 register.
345f2ea10aSNikunj Kela */
355f2ea10aSNikunj Kela
365f2ea10aSNikunj Kela #define SHMEM_SIZE (SZ_4K)
375f2ea10aSNikunj Kela #define SHMEM_SHIFT 12
385f2ea10aSNikunj Kela #define SHMEM_PAGE(x) (_UL((x) >> SHMEM_SHIFT))
395f2ea10aSNikunj Kela #define SHMEM_OFFSET(x) ((x) & (SHMEM_SIZE - 1))
405f2ea10aSNikunj Kela
411dc65580SPeng Fan /**
421dc65580SPeng Fan * struct scmi_smc - Structure representing a SCMI smc transport
431dc65580SPeng Fan *
44d1ff11d7SCristian Marussi * @irq: An optional IRQ for completion
451dc65580SPeng Fan * @cinfo: SCMI channel info
461dc65580SPeng Fan * @shmem: Transmit/Receive shared memory area
470bfdca8aSCristian Marussi * @shmem_lock: Lock to protect access to Tx/Rx shared memory area.
480bfdca8aSCristian Marussi * Used when NOT operating in atomic mode.
490bfdca8aSCristian Marussi * @inflight: Atomic flag to protect access to Tx/Rx shared memory area.
500bfdca8aSCristian Marussi * Used when operating in atomic mode.
511dc65580SPeng Fan * @func_id: smc/hvc call function id
525f2ea10aSNikunj Kela * @param_page: 4K page number of the shmem channel
535f2ea10aSNikunj Kela * @param_offset: Offset within the 4K page of the shmem channel
54da405477SNikunj Kela * @cap_id: smc/hvc doorbell's capability id to be used on Qualcomm virtual
55da405477SNikunj Kela * platforms
561dc65580SPeng Fan */
571dc65580SPeng Fan
581dc65580SPeng Fan struct scmi_smc {
59d1ff11d7SCristian Marussi int irq;
601dc65580SPeng Fan struct scmi_chan_info *cinfo;
611dc65580SPeng Fan struct scmi_shared_mem __iomem *shmem;
620bfdca8aSCristian Marussi /* Protect access to shmem area */
6318988265SSudeep Holla struct mutex shmem_lock;
640bfdca8aSCristian Marussi #define INFLIGHT_NONE MSG_TOKEN_MAX
650bfdca8aSCristian Marussi atomic_t inflight;
661f173951SSudeep Holla unsigned long func_id;
671f173951SSudeep Holla unsigned long param_page;
681f173951SSudeep Holla unsigned long param_offset;
69da405477SNikunj Kela unsigned long cap_id;
701dc65580SPeng Fan };
711dc65580SPeng Fan
smc_msg_done_isr(int irq,void * data)72dd820ee2SJim Quinlan static irqreturn_t smc_msg_done_isr(int irq, void *data)
73dd820ee2SJim Quinlan {
74dd820ee2SJim Quinlan struct scmi_smc *scmi_info = data;
75dd820ee2SJim Quinlan
76f716cbd3SCristian Marussi scmi_rx_callback(scmi_info->cinfo,
77f716cbd3SCristian Marussi shmem_read_header(scmi_info->shmem), NULL);
78dd820ee2SJim Quinlan
79dd820ee2SJim Quinlan return IRQ_HANDLED;
80dd820ee2SJim Quinlan }
81dd820ee2SJim Quinlan
smc_chan_available(struct device_node * of_node,int idx)827a75b7afSCristian Marussi static bool smc_chan_available(struct device_node *of_node, int idx)
831dc65580SPeng Fan {
847a75b7afSCristian Marussi struct device_node *np = of_parse_phandle(of_node, "shmem", 0);
858aa6e12bSSudeep Holla if (!np)
868aa6e12bSSudeep Holla return false;
878aa6e12bSSudeep Holla
888aa6e12bSSudeep Holla of_node_put(np);
891dc65580SPeng Fan return true;
901dc65580SPeng Fan }
911dc65580SPeng Fan
smc_channel_lock_init(struct scmi_smc * scmi_info)920bfdca8aSCristian Marussi static inline void smc_channel_lock_init(struct scmi_smc *scmi_info)
930bfdca8aSCristian Marussi {
940bfdca8aSCristian Marussi if (IS_ENABLED(CONFIG_ARM_SCMI_TRANSPORT_SMC_ATOMIC_ENABLE))
950bfdca8aSCristian Marussi atomic_set(&scmi_info->inflight, INFLIGHT_NONE);
960bfdca8aSCristian Marussi else
970bfdca8aSCristian Marussi mutex_init(&scmi_info->shmem_lock);
980bfdca8aSCristian Marussi }
990bfdca8aSCristian Marussi
smc_xfer_inflight(struct scmi_xfer * xfer,atomic_t * inflight)1000bfdca8aSCristian Marussi static bool smc_xfer_inflight(struct scmi_xfer *xfer, atomic_t *inflight)
1010bfdca8aSCristian Marussi {
1020bfdca8aSCristian Marussi int ret;
1030bfdca8aSCristian Marussi
1040bfdca8aSCristian Marussi ret = atomic_cmpxchg(inflight, INFLIGHT_NONE, xfer->hdr.seq);
1050bfdca8aSCristian Marussi
1060bfdca8aSCristian Marussi return ret == INFLIGHT_NONE;
1070bfdca8aSCristian Marussi }
1080bfdca8aSCristian Marussi
1090bfdca8aSCristian Marussi static inline void
smc_channel_lock_acquire(struct scmi_smc * scmi_info,struct scmi_xfer * xfer __maybe_unused)1100bfdca8aSCristian Marussi smc_channel_lock_acquire(struct scmi_smc *scmi_info,
1110bfdca8aSCristian Marussi struct scmi_xfer *xfer __maybe_unused)
1120bfdca8aSCristian Marussi {
1130bfdca8aSCristian Marussi if (IS_ENABLED(CONFIG_ARM_SCMI_TRANSPORT_SMC_ATOMIC_ENABLE))
1140bfdca8aSCristian Marussi spin_until_cond(smc_xfer_inflight(xfer, &scmi_info->inflight));
1150bfdca8aSCristian Marussi else
1160bfdca8aSCristian Marussi mutex_lock(&scmi_info->shmem_lock);
1170bfdca8aSCristian Marussi }
1180bfdca8aSCristian Marussi
smc_channel_lock_release(struct scmi_smc * scmi_info)1190bfdca8aSCristian Marussi static inline void smc_channel_lock_release(struct scmi_smc *scmi_info)
1200bfdca8aSCristian Marussi {
1210bfdca8aSCristian Marussi if (IS_ENABLED(CONFIG_ARM_SCMI_TRANSPORT_SMC_ATOMIC_ENABLE))
1220bfdca8aSCristian Marussi atomic_set(&scmi_info->inflight, INFLIGHT_NONE);
1230bfdca8aSCristian Marussi else
1240bfdca8aSCristian Marussi mutex_unlock(&scmi_info->shmem_lock);
1250bfdca8aSCristian Marussi }
1260bfdca8aSCristian Marussi
smc_chan_setup(struct scmi_chan_info * cinfo,struct device * dev,bool tx)1271dc65580SPeng Fan static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
1281dc65580SPeng Fan bool tx)
1291dc65580SPeng Fan {
1301dc65580SPeng Fan struct device *cdev = cinfo->dev;
131da405477SNikunj Kela unsigned long cap_id = ULONG_MAX;
1321dc65580SPeng Fan struct scmi_smc *scmi_info;
1331dc65580SPeng Fan resource_size_t size;
1341dc65580SPeng Fan struct resource res;
1351dc65580SPeng Fan struct device_node *np;
1361dc65580SPeng Fan u32 func_id;
137d1ff11d7SCristian Marussi int ret;
1381dc65580SPeng Fan
1391dc65580SPeng Fan if (!tx)
1401dc65580SPeng Fan return -ENODEV;
1411dc65580SPeng Fan
1421dc65580SPeng Fan scmi_info = devm_kzalloc(dev, sizeof(*scmi_info), GFP_KERNEL);
1431dc65580SPeng Fan if (!scmi_info)
1441dc65580SPeng Fan return -ENOMEM;
1451dc65580SPeng Fan
1461dc65580SPeng Fan np = of_parse_phandle(cdev->of_node, "shmem", 0);
147da042eb4SKrzysztof Kozlowski if (!of_device_is_compatible(np, "arm,scmi-shmem")) {
148da042eb4SKrzysztof Kozlowski of_node_put(np);
149507cd4d2SSudeep Holla return -ENXIO;
150da042eb4SKrzysztof Kozlowski }
151507cd4d2SSudeep Holla
1521dc65580SPeng Fan ret = of_address_to_resource(np, 0, &res);
1531dc65580SPeng Fan of_node_put(np);
1541dc65580SPeng Fan if (ret) {
1551dc65580SPeng Fan dev_err(cdev, "failed to get SCMI Tx shared memory\n");
1561dc65580SPeng Fan return ret;
1571dc65580SPeng Fan }
1581dc65580SPeng Fan
1591dc65580SPeng Fan size = resource_size(&res);
1601dc65580SPeng Fan scmi_info->shmem = devm_ioremap(dev, res.start, size);
1611dc65580SPeng Fan if (!scmi_info->shmem) {
1621dc65580SPeng Fan dev_err(dev, "failed to ioremap SCMI Tx shared memory\n");
1631dc65580SPeng Fan return -EADDRNOTAVAIL;
1641dc65580SPeng Fan }
1651dc65580SPeng Fan
1661dc65580SPeng Fan ret = of_property_read_u32(dev->of_node, "arm,smc-id", &func_id);
1671dc65580SPeng Fan if (ret < 0)
1681dc65580SPeng Fan return ret;
1691dc65580SPeng Fan
170da405477SNikunj Kela if (of_device_is_compatible(dev->of_node, "qcom,scmi-smc")) {
171da405477SNikunj Kela void __iomem *ptr = (void __iomem *)scmi_info->shmem + size - 8;
172da405477SNikunj Kela /* The capability-id is kept in last 8 bytes of shmem.
173da405477SNikunj Kela * +-------+ <-- 0
174da405477SNikunj Kela * | shmem |
175da405477SNikunj Kela * +-------+ <-- size - 8
176da405477SNikunj Kela * | capId |
177da405477SNikunj Kela * +-------+ <-- size
178da405477SNikunj Kela */
179da405477SNikunj Kela memcpy_fromio(&cap_id, ptr, sizeof(cap_id));
180da405477SNikunj Kela }
181da405477SNikunj Kela
1825f2ea10aSNikunj Kela if (of_device_is_compatible(dev->of_node, "arm,scmi-smc-param")) {
1835f2ea10aSNikunj Kela scmi_info->param_page = SHMEM_PAGE(res.start);
1845f2ea10aSNikunj Kela scmi_info->param_offset = SHMEM_OFFSET(res.start);
1855f2ea10aSNikunj Kela }
186dd820ee2SJim Quinlan /*
187dd820ee2SJim Quinlan * If there is an interrupt named "a2p", then the service and
188dd820ee2SJim Quinlan * completion of a message is signaled by an interrupt rather than by
189dd820ee2SJim Quinlan * the return of the SMC call.
190dd820ee2SJim Quinlan */
191d1ff11d7SCristian Marussi scmi_info->irq = of_irq_get_byname(cdev->of_node, "a2p");
192d1ff11d7SCristian Marussi if (scmi_info->irq > 0) {
193d1ff11d7SCristian Marussi ret = request_irq(scmi_info->irq, smc_msg_done_isr,
194d1ff11d7SCristian Marussi IRQF_NO_SUSPEND, dev_name(dev), scmi_info);
195dd820ee2SJim Quinlan if (ret) {
196dd820ee2SJim Quinlan dev_err(dev, "failed to setup SCMI smc irq\n");
197dd820ee2SJim Quinlan return ret;
198dd820ee2SJim Quinlan }
199f716cbd3SCristian Marussi } else {
200f716cbd3SCristian Marussi cinfo->no_completion_irq = true;
201dd820ee2SJim Quinlan }
202dd820ee2SJim Quinlan
2031dc65580SPeng Fan scmi_info->func_id = func_id;
204da405477SNikunj Kela scmi_info->cap_id = cap_id;
2051dc65580SPeng Fan scmi_info->cinfo = cinfo;
2060bfdca8aSCristian Marussi smc_channel_lock_init(scmi_info);
2071dc65580SPeng Fan cinfo->transport_info = scmi_info;
2081dc65580SPeng Fan
2091dc65580SPeng Fan return 0;
2101dc65580SPeng Fan }
2111dc65580SPeng Fan
smc_chan_free(int id,void * p,void * data)2121dc65580SPeng Fan static int smc_chan_free(int id, void *p, void *data)
2131dc65580SPeng Fan {
2141dc65580SPeng Fan struct scmi_chan_info *cinfo = p;
2151dc65580SPeng Fan struct scmi_smc *scmi_info = cinfo->transport_info;
2161dc65580SPeng Fan
217*f1d71576SAndre Przywara /*
218*f1d71576SAndre Przywara * Different protocols might share the same chan info, so a previous
219*f1d71576SAndre Przywara * smc_chan_free call might have already freed the structure.
220*f1d71576SAndre Przywara */
221*f1d71576SAndre Przywara if (!scmi_info)
222*f1d71576SAndre Przywara return 0;
223*f1d71576SAndre Przywara
224d1ff11d7SCristian Marussi /* Ignore any possible further reception on the IRQ path */
225d1ff11d7SCristian Marussi if (scmi_info->irq > 0)
226d1ff11d7SCristian Marussi free_irq(scmi_info->irq, scmi_info);
227d1ff11d7SCristian Marussi
2281dc65580SPeng Fan cinfo->transport_info = NULL;
2291dc65580SPeng Fan scmi_info->cinfo = NULL;
2301dc65580SPeng Fan
2311dc65580SPeng Fan return 0;
2321dc65580SPeng Fan }
2331dc65580SPeng Fan
smc_send_message(struct scmi_chan_info * cinfo,struct scmi_xfer * xfer)2341dc65580SPeng Fan static int smc_send_message(struct scmi_chan_info *cinfo,
2351dc65580SPeng Fan struct scmi_xfer *xfer)
2361dc65580SPeng Fan {
2371dc65580SPeng Fan struct scmi_smc *scmi_info = cinfo->transport_info;
2381dc65580SPeng Fan struct arm_smccc_res res;
2391dc65580SPeng Fan
240f716cbd3SCristian Marussi /*
2410bfdca8aSCristian Marussi * Channel will be released only once response has been
242f716cbd3SCristian Marussi * surely fully retrieved, so after .mark_txdone()
243f716cbd3SCristian Marussi */
2440bfdca8aSCristian Marussi smc_channel_lock_acquire(scmi_info, xfer);
2451dc65580SPeng Fan
24659172b21SCristian Marussi shmem_tx_prepare(scmi_info->shmem, xfer, cinfo);
2471dc65580SPeng Fan
248da405477SNikunj Kela if (scmi_info->cap_id != ULONG_MAX)
249da405477SNikunj Kela arm_smccc_1_1_invoke(scmi_info->func_id, scmi_info->cap_id, 0,
250da405477SNikunj Kela 0, 0, 0, 0, 0, &res);
251da405477SNikunj Kela else
2521f173951SSudeep Holla arm_smccc_1_1_invoke(scmi_info->func_id, scmi_info->param_page,
253da405477SNikunj Kela scmi_info->param_offset, 0, 0, 0, 0, 0,
254da405477SNikunj Kela &res);
255dd820ee2SJim Quinlan
256f7199cf4SSudeep Holla /* Only SMCCC_RET_NOT_SUPPORTED is valid error code */
257f716cbd3SCristian Marussi if (res.a0) {
2580bfdca8aSCristian Marussi smc_channel_lock_release(scmi_info);
259f7199cf4SSudeep Holla return -EOPNOTSUPP;
260f716cbd3SCristian Marussi }
261f716cbd3SCristian Marussi
262f7199cf4SSudeep Holla return 0;
2631dc65580SPeng Fan }
2641dc65580SPeng Fan
smc_fetch_response(struct scmi_chan_info * cinfo,struct scmi_xfer * xfer)2651dc65580SPeng Fan static void smc_fetch_response(struct scmi_chan_info *cinfo,
2661dc65580SPeng Fan struct scmi_xfer *xfer)
2671dc65580SPeng Fan {
2681dc65580SPeng Fan struct scmi_smc *scmi_info = cinfo->transport_info;
2691dc65580SPeng Fan
2701dc65580SPeng Fan shmem_fetch_response(scmi_info->shmem, xfer);
2711dc65580SPeng Fan }
2721dc65580SPeng Fan
smc_mark_txdone(struct scmi_chan_info * cinfo,int ret,struct scmi_xfer * __unused)27394d0cd1dSCristian Marussi static void smc_mark_txdone(struct scmi_chan_info *cinfo, int ret,
27494d0cd1dSCristian Marussi struct scmi_xfer *__unused)
275f716cbd3SCristian Marussi {
276f716cbd3SCristian Marussi struct scmi_smc *scmi_info = cinfo->transport_info;
277f716cbd3SCristian Marussi
2780bfdca8aSCristian Marussi smc_channel_lock_release(scmi_info);
279f716cbd3SCristian Marussi }
280f716cbd3SCristian Marussi
2813de7b830SRikard Falkeborn static const struct scmi_transport_ops scmi_smc_ops = {
2821dc65580SPeng Fan .chan_available = smc_chan_available,
2831dc65580SPeng Fan .chan_setup = smc_chan_setup,
2841dc65580SPeng Fan .chan_free = smc_chan_free,
2851dc65580SPeng Fan .send_message = smc_send_message,
286f716cbd3SCristian Marussi .mark_txdone = smc_mark_txdone,
2871dc65580SPeng Fan .fetch_response = smc_fetch_response,
2881dc65580SPeng Fan };
2891dc65580SPeng Fan
2901dc65580SPeng Fan const struct scmi_desc scmi_smc_desc = {
2911dc65580SPeng Fan .ops = &scmi_smc_ops,
2921dc65580SPeng Fan .max_rx_timeout_ms = 30,
2937adb2c8aSEtienne Carriere .max_msg = 20,
2941dc65580SPeng Fan .max_msg_size = 128,
295117542b8SCristian Marussi /*
296117542b8SCristian Marussi * Setting .sync_cmds_atomic_replies to true for SMC assumes that,
297117542b8SCristian Marussi * once the SMC instruction has completed successfully, the issued
298117542b8SCristian Marussi * SCMI command would have been already fully processed by the SCMI
299117542b8SCristian Marussi * platform firmware and so any possible response value expected
300117542b8SCristian Marussi * for the issued command will be immmediately ready to be fetched
301117542b8SCristian Marussi * from the shared memory area.
302117542b8SCristian Marussi */
303117542b8SCristian Marussi .sync_cmds_completed_on_ret = true,
3040bfdca8aSCristian Marussi .atomic_enabled = IS_ENABLED(CONFIG_ARM_SCMI_TRANSPORT_SMC_ATOMIC_ENABLE),
3051dc65580SPeng Fan };
306