text: // SPDX-License-Identifier: GPL-2.0
  /*
   * Copyright (C) STMicroelectronics 2018 - All Rights Reserved
   * Authors: Ludovic Barre <ludovic.barre@st.com> for STMicroelectronics.
   *          Fabien Dessenne <fabien.dessenne@st.com> for STMicroelectronics.
   */
  
  #include <linux/arm-smccc.h>
  #include <linux/dma-mapping.h>
  #include <linux/interrupt.h>
  #include <linux/io.h>
  #include <linux/mailbox_client.h>
  #include <linux/mfd/syscon.h>
  #include <linux/module.h>
  #include <linux/of_address.h>
  #include <linux/of_device.h>
  #include <linux/of_reserved_mem.h>
  #include <linux/pm_wakeirq.h>
  #include <linux/regmap.h>
  #include <linux/remoteproc.h>
  #include <linux/reset.h>
  #include <linux/slab.h>
  #include <linux/workqueue.h>
  
  #include "remoteproc_internal.h"
  
  #define HOLD_BOOT		0
  #define RELEASE_BOOT		1
  
  #define MBOX_NB_VQ		2
  #define MBOX_NB_MBX		3
  
  #define STM32_SMC_RCC		0x82001000
  #define STM32_SMC_REG_WRITE	0x1
  
  #define STM32_MBX_VQ0		"vq0"
  #define STM32_MBX_VQ0_ID	0
  #define STM32_MBX_VQ1		"vq1"
  #define STM32_MBX_VQ1_ID	1
  #define STM32_MBX_SHUTDOWN	"shutdown"
  
  struct stm32_syscon {
  	struct regmap *map;
  	u32 reg;
  	u32 mask;
  };
  
  struct stm32_rproc_mem {
  	char name[20];
  	void __iomem *cpu_addr;
  	phys_addr_t bus_addr;
  	u32 dev_addr;
  	size_t size;
  };
  
  struct stm32_rproc_mem_ranges {
  	u32 dev_addr;
  	u32 bus_addr;
  	u32 size;
  };
  
  struct stm32_mbox {
  	const unsigned char name[10];
  	struct mbox_chan *chan;
  	struct mbox_client client;
  	struct work_struct vq_work;
  	int vq_id;
  };
  
  struct stm32_rproc {
  	struct reset_control *rst;
  	struct stm32_syscon hold_boot;
  	struct stm32_syscon pdds;
  	int wdg_irq;
  	u32 nb_rmems;
  	struct stm32_rproc_mem *rmems;
  	struct stm32_mbox mb[MBOX_NB_MBX];
  	struct workqueue_struct *workqueue;
  	bool secured_soc;
  };
  
  static int stm32_rproc_pa_to_da(struct rproc *rproc, phys_addr_t pa, u64 *da)
  {
  	unsigned int i;
  	struct stm32_rproc *ddata = rproc->priv;
  	struct stm32_rproc_mem *p_mem;
  
  	for (i = 0; i < ddata->nb_rmems; i++) {
  		p_mem = &ddata->rmems[i];
  
  		if (pa < p_mem->bus_addr ||
  		    pa >= p_mem->bus_addr + p_mem->size)
  			continue;
  		*da = pa - p_mem->bus_addr + p_mem->dev_addr;
  		dev_dbg(rproc->dev.parent, "pa %pa to da %llx\n", &pa, *da);
  		return 0;
  	}
  
  	return -EINVAL;
  }
  
  static int stm32_rproc_mem_alloc(struct rproc *rproc,
  				 struct rproc_mem_entry *mem)
  {
  	struct device *dev = rproc->dev.parent;
  	void *va;
  
  	dev_dbg(dev, "map memory: %pa+%x\n", &mem->dma, mem->len);
  	va = ioremap_wc(mem->dma, mem->len);
  	if (IS_ERR_OR_NULL(va)) {
  		dev_err(dev, "Unable to map memory region: %pa+%x\n",
  			&mem->dma, mem->len);
  		return -ENOMEM;
  	}
  
  	/* Update memory entry va */
  	mem->va = va;
  
  	return 0;
  }
  
  static int stm32_rproc_mem_release(struct rproc *rproc,
  				   struct rproc_mem_entry *mem)
  {
  	dev_dbg(rproc->dev.parent, "unmap memory: %pa\n", &mem->dma);
  	iounmap(mem->va);
  
  	return 0;
  }
  
  static int stm32_rproc_of_memory_translations(struct rproc *rproc)
  {
  	struct device *parent, *dev = rproc->dev.parent;
  	struct stm32_rproc *ddata = rproc->priv;
  	struct device_node *np;
  	struct stm32_rproc_mem *p_mems;
  	struct stm32_rproc_mem_ranges *mem_range;
  	int cnt, array_size, i, ret = 0;
  
  	parent = dev->parent;
  	np = parent->of_node;
  
  	cnt = of_property_count_elems_of_size(np, "dma-ranges",
  					      sizeof(*mem_range));
  	if (cnt <= 0) {
  		dev_err(dev, "%s: dma-ranges property not defined\n", __func__);
  		return -EINVAL;
  	}
  
  	p_mems = devm_kcalloc(dev, cnt, sizeof(*p_mems), GFP_KERNEL);
  	if (!p_mems)
  		return -ENOMEM;
  	mem_range = kcalloc(cnt, sizeof(*mem_range), GFP_KERNEL);
  	if (!mem_range)
  		return -ENOMEM;
  
  	array_size = cnt * sizeof(struct stm32_rproc_mem_ranges) / sizeof(u32);
  
  	ret = of_property_read_u32_array(np, "dma-ranges",
  					 (u32 *)mem_range, array_size);
  	if (ret) {
  		dev_err(dev, "error while get dma-ranges property: %x\n", ret);
  		goto free_mem;
  	}
  
  	for (i = 0; i < cnt; i++) {
  		p_mems[i].bus_addr = mem_range[i].bus_addr;
  		p_mems[i].dev_addr = mem_range[i].dev_addr;
  		p_mems[i].size     = mem_range[i].size;
  
  		dev_dbg(dev, "memory range[%i]: da %#x, pa %pa, size %#zx:\n",
  			i, p_mems[i].dev_addr, &p_mems[i].bus_addr,
  			p_mems[i].size);
  	}
  
  	ddata->rmems = p_mems;
  	ddata->nb_rmems = cnt;
  
  free_mem:
  	kfree(mem_range);
  	return ret;
  }
  
  static int stm32_rproc_mbox_idx(struct rproc *rproc, const unsigned char *name)
  {
  	struct stm32_rproc *ddata = rproc->priv;
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(ddata->mb); i++) {
  		if (!strncmp(ddata->mb[i].name, name, strlen(name)))
  			return i;
  	}
  	dev_err(&rproc->dev, "mailbox %s not found\n", name);
  
  	return -EINVAL;
  }
  
  static int stm32_rproc_elf_load_rsc_table(struct rproc *rproc,
  					  const struct firmware *fw)
  {
  	if (rproc_elf_load_rsc_table(rproc, fw))
  		dev_warn(&rproc->dev, "no resource table found for this firmware\n");
  
  	return 0;
  }
  
  static int stm32_rproc_parse_fw(struct rproc *rproc, const struct firmware *fw)
  {
  	struct device *dev = rproc->dev.parent;
  	struct device_node *np = dev->of_node;
  	struct of_phandle_iterator it;
  	struct rproc_mem_entry *mem;
  	struct reserved_mem *rmem;
  	u64 da;
  	int index = 0;
  
  	/* Register associated reserved memory regions */
  	of_phandle_iterator_init(&it, np, "memory-region", NULL, 0);
  	while (of_phandle_iterator_next(&it) == 0) {
  		rmem = of_reserved_mem_lookup(it.node);
  		if (!rmem) {
  			dev_err(dev, "unable to acquire memory-region\n");
  			return -EINVAL;
  		}
  
  		if (stm32_rproc_pa_to_da(rproc, rmem->base, &da) < 0) {
  			dev_err(dev, "memory region not valid %pa\n",
  				&rmem->base);
  			return -EINVAL;
  		}
  
  		/*  No need to map vdev buffer */
  		if (strcmp(it.node->name, "vdev0buffer")) {
  			/* Register memory region */
  			mem = rproc_mem_entry_init(dev, NULL,
  						   (dma_addr_t)rmem->base,
  						   rmem->size, da,
  						   stm32_rproc_mem_alloc,
  						   stm32_rproc_mem_release,
  						   it.node->name);
  
  			if (mem)
  				rproc_coredump_add_segment(rproc, da,
  							   rmem->size);
  		} else {
  			/* Register reserved memory for vdev buffer alloc */
  			mem = rproc_of_resm_mem_entry_init(dev, index,
  							   rmem->size,
  							   rmem->base,
  							   it.node->name);
  		}
  
  		if (!mem)
  			return -ENOMEM;
  
  		rproc_add_carveout(rproc, mem);
  		index++;
  	}
  
  	return stm32_rproc_elf_load_rsc_table(rproc, fw);
  }
  
  static irqreturn_t stm32_rproc_wdg(int irq, void *data)
  {
  	struct rproc *rproc = data;
  
  	rproc_report_crash(rproc, RPROC_WATCHDOG);
  
  	return IRQ_HANDLED;
  }
  
  static void stm32_rproc_mb_vq_work(struct work_struct *work)
  {
  	struct stm32_mbox *mb = container_of(work, struct stm32_mbox, vq_work);
  	struct rproc *rproc = dev_get_drvdata(mb->client.dev);
  
  	if (rproc_vq_interrupt(rproc, mb->vq_id) == IRQ_NONE)
  		dev_dbg(&rproc->dev, "no message found in vq%d\n", mb->vq_id);
  }
  
  static void stm32_rproc_mb_callback(struct mbox_client *cl, void *data)
  {
  	struct rproc *rproc = dev_get_drvdata(cl->dev);
  	struct stm32_mbox *mb = container_of(cl, struct stm32_mbox, client);
  	struct stm32_rproc *ddata = rproc->priv;
  
  	queue_work(ddata->workqueue, &mb->vq_work);
  }
  
  static void stm32_rproc_free_mbox(struct rproc *rproc)
  {
  	struct stm32_rproc *ddata = rproc->priv;
  	unsigned int i;
  
  	for (i = 0; i < ARRAY_SIZE(ddata->mb); i++) {
  		if (ddata->mb[i].chan)
  			mbox_free_channel(ddata->mb[i].chan);
  		ddata->mb[i].chan = NULL;
  	}
  }
  
  static const struct stm32_mbox stm32_rproc_mbox[MBOX_NB_MBX] = {
  	{
  		.name = STM32_MBX_VQ0,
  		.vq_id = STM32_MBX_VQ0_ID,
  		.client = {
  			.rx_callback = stm32_rproc_mb_callback,
  			.tx_block = false,
  		},
  	},
  	{
  		.name = STM32_MBX_VQ1,
  		.vq_id = STM32_MBX_VQ1_ID,
  		.client = {
  			.rx_callback = stm32_rproc_mb_callback,
  			.tx_block = false,
  		},
  	},
  	{
  		.name = STM32_MBX_SHUTDOWN,
  		.vq_id = -1,
  		.client = {
  			.tx_block = true,
  			.tx_done = NULL,
  			.tx_tout = 500, /* 500 ms time out */
  		},
  	}
  };
  
  static int stm32_rproc_request_mbox(struct rproc *rproc)
  {
  	struct stm32_rproc *ddata = rproc->priv;
  	struct device *dev = &rproc->dev;
  	unsigned int i;
  	int j;
  	const unsigned char *name;
  	struct mbox_client *cl;
  
  	/* Initialise mailbox structure table */
  	memcpy(ddata->mb, stm32_rproc_mbox, sizeof(stm32_rproc_mbox));
  
  	for (i = 0; i < MBOX_NB_MBX; i++) {
  		name = ddata->mb[i].name;
  
  		cl = &ddata->mb[i].client;
  		cl->dev = dev->parent;
  
  		ddata->mb[i].chan = mbox_request_channel_byname(cl, name);
  		if (IS_ERR(ddata->mb[i].chan)) {
  			if (PTR_ERR(ddata->mb[i].chan) == -EPROBE_DEFER)
  				goto err_probe;
  			dev_warn(dev, "cannot get %s mbox\n", name);
  			ddata->mb[i].chan = NULL;
  		}
  		if (ddata->mb[i].vq_id >= 0) {
  			INIT_WORK(&ddata->mb[i].vq_work,
  				  stm32_rproc_mb_vq_work);
  		}
  	}
  
  	return 0;
  
  err_probe:
  	for (j = i - 1; j >= 0; j--)
  		if (ddata->mb[j].chan)
  			mbox_free_channel(ddata->mb[j].chan);
  	return -EPROBE_DEFER;
  }
  
  static int stm32_rproc_set_hold_boot(struct rproc *rproc, bool hold)
  {
  	struct stm32_rproc *ddata = rproc->priv;
  	struct stm32_syscon hold_boot = ddata->hold_boot;
  	struct arm_smccc_res smc_res;
  	int val, err;
  
  	val = hold ? HOLD_BOOT : RELEASE_BOOT;
  
  	if (IS_ENABLED(CONFIG_HAVE_ARM_SMCCC) && ddata->secured_soc) {
  		arm_smccc_smc(STM32_SMC_RCC, STM32_SMC_REG_WRITE,
  			      hold_boot.reg, val, 0, 0, 0, 0, &smc_res);
  		err = smc_res.a0;
  	} else {
  		err = regmap_update_bits(hold_boot.map, hold_boot.reg,
  					 hold_boot.mask, val);
  	}
  
  	if (err)
  		dev_err(&rproc->dev, "failed to set hold boot\n");
  
  	return err;
  }
  
  static void stm32_rproc_add_coredump_trace(struct rproc *rproc)
  {
  	struct rproc_debug_trace *trace;
  	struct rproc_dump_segment *segment;
  	bool already_added;
  
  	list_for_each_entry(trace, &rproc->traces, node) {
  		already_added = false;
  
  		list_for_each_entry(segment, &rproc->dump_segments, node) {
  			if (segment->da == trace->trace_mem.da) {
  				already_added = true;
  				break;
  			}
  		}
  
  		if (!already_added)
  			rproc_coredump_add_segment(rproc, trace->trace_mem.da,
  						   trace->trace_mem.len);
  	}
  }
  
  static int stm32_rproc_start(struct rproc *rproc)
  {
  	struct stm32_rproc *ddata = rproc->priv;
  	int err;
  
  	stm32_rproc_add_coredump_trace(rproc);
  
  	/* clear remote proc Deep Sleep */
  	if (ddata->pdds.map) {
  		err = regmap_update_bits(ddata->pdds.map, ddata->pdds.reg,
  					 ddata->pdds.mask, 0);
  		if (err) {
  			dev_err(&rproc->dev, "failed to clear pdds\n");
  			return err;
  		}
  	}
  
  	err = stm32_rproc_set_hold_boot(rproc, false);
  	if (err)
  		return err;
  
  	return stm32_rproc_set_hold_boot(rproc, true);
  }
  
  static int stm32_rproc_stop(struct rproc *rproc)
  {
  	struct stm32_rproc *ddata = rproc->priv;
  	int err, dummy_data, idx;
  
  	/* request shutdown of the remote processor */
  	if (rproc->state != RPROC_OFFLINE) {
  		idx = stm32_rproc_mbox_idx(rproc, STM32_MBX_SHUTDOWN);
  		if (idx >= 0 && ddata->mb[idx].chan) {
  			/* a dummy data is sent to allow to block on transmit */
  			err = mbox_send_message(ddata->mb[idx].chan,
  						&dummy_data);
  			if (err < 0)
  				dev_warn(&rproc->dev, "warning: remote FW shutdown without ack\n");
  		}
  	}
  
  	err = stm32_rproc_set_hold_boot(rproc, true);
  	if (err)
  		return err;
  
  	err = reset_control_assert(ddata->rst);
  	if (err) {
  		dev_err(&rproc->dev, "failed to assert the reset\n");
  		return err;
  	}
  
  	/* to allow platform Standby power mode, set remote proc Deep Sleep */
  	if (ddata->pdds.map) {
  		err = regmap_update_bits(ddata->pdds.map, ddata->pdds.reg,
  					 ddata->pdds.mask, 1);
  		if (err) {
  			dev_err(&rproc->dev, "failed to set pdds\n");
  			return err;
  		}
  	}
  
  	return 0;
  }
  
  static void stm32_rproc_kick(struct rproc *rproc, int vqid)
  {
  	struct stm32_rproc *ddata = rproc->priv;
  	unsigned int i;
  	int err;
  
  	if (WARN_ON(vqid >= MBOX_NB_VQ))
  		return;
  
  	for (i = 0; i < MBOX_NB_MBX; i++) {
  		if (vqid != ddata->mb[i].vq_id)
  			continue;
  		if (!ddata->mb[i].chan)
  			return;
  		err = mbox_send_message(ddata->mb[i].chan, (void *)(long)vqid);
  		if (err < 0)
  			dev_err(&rproc->dev, "%s: failed (%s, err:%d)\n",
  				__func__, ddata->mb[i].name, err);
  		return;
  	}
  }
  
  static struct rproc_ops st_rproc_ops = {
  	.start		= stm32_rproc_start,
  	.stop		= stm32_rproc_stop,
  	.kick		= stm32_rproc_kick,
  	.load		= rproc_elf_load_segments,
  	.parse_fw	= stm32_rproc_parse_fw,
  	.find_loaded_rsc_table = rproc_elf_find_loaded_rsc_table,
  	.sanity_check	= rproc_elf_sanity_check,
  	.get_boot_addr	= rproc_elf_get_boot_addr,
  };
  
  static const struct of_device_id stm32_rproc_match[] = {
  	{ .compatible = "st,stm32mp1-m4" },
  	{},
  };
  MODULE_DEVICE_TABLE(of, stm32_rproc_match);
  
  static int stm32_rproc_get_syscon(struct device_node *np, const char *prop,
  				  struct stm32_syscon *syscon)
  {
  	int err = 0;
  
  	syscon->map = syscon_regmap_lookup_by_phandle(np, prop);
  	if (IS_ERR(syscon->map)) {
  		err = PTR_ERR(syscon->map);
  		syscon->map = NULL;
  		goto out;
  	}
  
  	err = of_property_read_u32_index(np, prop, 1, &syscon->reg);
  	if (err)
  		goto out;
  
  	err = of_property_read_u32_index(np, prop, 2, &syscon->mask);
  
  out:
  	return err;
  }
  
  static int stm32_rproc_parse_dt(struct platform_device *pdev)
  {
  	struct device *dev = &pdev->dev;
  	struct device_node *np = dev->of_node;
  	struct rproc *rproc = platform_get_drvdata(pdev);
  	struct stm32_rproc *ddata = rproc->priv;
  	struct stm32_syscon tz;
  	unsigned int tzen;
  	int err, irq;
  
  	irq = platform_get_irq(pdev, 0);
  	if (irq == -EPROBE_DEFER)
  		return -EPROBE_DEFER;
  
  	if (irq > 0) {
  		err = devm_request_irq(dev, irq, stm32_rproc_wdg, 0,
  				       dev_name(dev), rproc);
  		if (err) {
  			dev_err(dev, "failed to request wdg irq\n");
  			return err;
  		}
  
  		ddata->wdg_irq = irq;
  
  		if (of_property_read_bool(np, "wakeup-source")) {
  			device_init_wakeup(dev, true);
  			dev_pm_set_wake_irq(dev, irq);
  		}
  
  		dev_info(dev, "wdg irq registered\n");
  	}
  
  	ddata->rst = devm_reset_control_get_by_index(dev, 0);
  	if (IS_ERR(ddata->rst)) {
  		dev_err(dev, "failed to get mcu reset\n");
  		return PTR_ERR(ddata->rst);
  	}
  
  	/*
  	 * if platform is secured the hold boot bit must be written by
  	 * smc call and read normally.
  	 * if not secure the hold boot bit could be read/write normally
  	 */
  	err = stm32_rproc_get_syscon(np, "st,syscfg-tz", &tz);
  	if (err) {
  		dev_err(dev, "failed to get tz syscfg\n");
  		return err;
  	}
  
  	err = regmap_read(tz.map, tz.reg, &tzen);
  	if (err) {
  		dev_err(&rproc->dev, "failed to read tzen\n");
  		return err;
  	}
  	ddata->secured_soc = tzen & tz.mask;
  
  	err = stm32_rproc_get_syscon(np, "st,syscfg-holdboot",
  				     &ddata->hold_boot);
  	if (err) {
  		dev_err(dev, "failed to get hold boot\n");
  		return err;
  	}
  
  	err = stm32_rproc_get_syscon(np, "st,syscfg-pdds", &ddata->pdds);
  	if (err)
  		dev_info(dev, "failed to get pdds\n");
  
  	rproc->auto_boot = of_property_read_bool(np, "st,auto-boot");
  
  	return stm32_rproc_of_memory_translations(rproc);
  }
  
  static int stm32_rproc_probe(struct platform_device *pdev)
  {
  	struct device *dev = &pdev->dev;
  	struct stm32_rproc *ddata;
  	struct device_node *np = dev->of_node;
  	struct rproc *rproc;
  	int ret;
  
  	ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
  	if (ret)
  		return ret;
  
  	rproc = rproc_alloc(dev, np->name, &st_rproc_ops, NULL, sizeof(*ddata));
  	if (!rproc)
  		return -ENOMEM;
  
  	rproc_coredump_set_elf_info(rproc, ELFCLASS32, EM_NONE);
  	rproc->has_iommu = false;
  	ddata = rproc->priv;
  	ddata->workqueue = create_workqueue(dev_name(dev));
  	if (!ddata->workqueue) {
  		dev_err(dev, "cannot create workqueue\n");
  		ret = -ENOMEM;
  		goto free_rproc;
  	}
  
  	platform_set_drvdata(pdev, rproc);
  
  	ret = stm32_rproc_parse_dt(pdev);
  	if (ret)
  		goto free_wkq;
  
  	ret = stm32_rproc_request_mbox(rproc);
  	if (ret)
  		goto free_rproc;
  
  	ret = rproc_add(rproc);
  	if (ret)
  		goto free_mb;
  
  	return 0;
  
  free_mb:
  	stm32_rproc_free_mbox(rproc);
  free_wkq:
  	destroy_workqueue(ddata->workqueue);
  free_rproc:
  	if (device_may_wakeup(dev)) {
  		dev_pm_clear_wake_irq(dev);
  		device_init_wakeup(dev, false);
  	}
  	rproc_free(rproc);
  	return ret;
  }
  
  static int stm32_rproc_remove(struct platform_device *pdev)
  {
  	struct rproc *rproc = platform_get_drvdata(pdev);
  	struct stm32_rproc *ddata = rproc->priv;
  	struct device *dev = &pdev->dev;
  
  	if (atomic_read(&rproc->power) > 0)
  		rproc_shutdown(rproc);
  
  	rproc_del(rproc);
  	stm32_rproc_free_mbox(rproc);
  	destroy_workqueue(ddata->workqueue);
  
  	if (device_may_wakeup(dev)) {
  		dev_pm_clear_wake_irq(dev);
  		device_init_wakeup(dev, false);
  	}
  	rproc_free(rproc);
  
  	return 0;
  }
  
  static int __maybe_unused stm32_rproc_suspend(struct device *dev)
  {
  	struct rproc *rproc = dev_get_drvdata(dev);
  	struct stm32_rproc *ddata = rproc->priv;
  
  	if (device_may_wakeup(dev))
  		return enable_irq_wake(ddata->wdg_irq);
  
  	return 0;
  }
  
  static int __maybe_unused stm32_rproc_resume(struct device *dev)
  {
  	struct rproc *rproc = dev_get_drvdata(dev);
  	struct stm32_rproc *ddata = rproc->priv;
  
  	if (device_may_wakeup(dev))
  		return disable_irq_wake(ddata->wdg_irq);
  
  	return 0;
  }
  
  static SIMPLE_DEV_PM_OPS(stm32_rproc_pm_ops,
  			 stm32_rproc_suspend, stm32_rproc_resume);
  
  static struct platform_driver stm32_rproc_driver = {
  	.probe = stm32_rproc_probe,
  	.remove = stm32_rproc_remove,
  	.driver = {
  		.name = "stm32-rproc",
  		.pm = &stm32_rproc_pm_ops,
  		.of_match_table = of_match_ptr(stm32_rproc_match),
  	},
  };
  module_platform_driver(stm32_rproc_driver);
  
  MODULE_DESCRIPTION("STM32 Remote Processor Control Driver");
  MODULE_AUTHOR("Ludovic Barre <ludovic.barre@st.com>");
  MODULE_AUTHOR("Fabien Dessenne <fabien.dessenne@st.com>");
  MODULE_LICENSE("GPL v2");
  
  