remoteproc/wkup_m3: add a remoteproc driver for TI Wakeup M3

Add a remoteproc driver to load the firmware and boot a small
Wakeup M3 processor present on TI AM33xx and AM43xx SoCs. This
Wakeup M3 remote processor is an integrated Cortex M3 that allows
the SoC to enter the lowest possible power state by taking control
from the MPU after it has gone into its own low power state and
shutting off any additional peripherals.

The Wakeup M3 processor has two internal memory regions - 16 kB of
unified instruction memory called UMEM used to store executable
code, and 8 kB of data memory called DMEM used for all data sections.
The Wakeup M3 processor executes its code entirely from within the
UMEM and uses the DMEM for any data. It does not use any external
memory or any other external resources. The device address view has
the UMEM at address 0x0 and DMEM at address 0x80000, and these are
computed automatically within the driver based on relative address
calculation from the corresponding device tree IOMEM resources.
These device addresses are used to aid the core remoteproc ELF
loader code to properly translate and load the firmware segments
through the .rproc_da_to_va ops.

Signed-off-by: Dave Gerlach <[e-mail]>
Signed-off-by: Suman Anna <[e-mail]>
Signed-off-by: Ohad Ben-Cohen <[e-mail]>

drivers/remoteproc/Kconfig

···
 	  This can be either built-in or a loadable module.
 	  If unsure say N.
 
+config WKUP_M3_RPROC
+	tristate "AMx3xx Wakeup M3 remoteproc support"
+	depends on SOC_AM33XX || SOC_AM43XX
+	select REMOTEPROC
+	help
+	  Say y here to support Wakeup M3 remote processor on TI AM33xx
+	  and AM43xx family of SoCs.
+
+	  Required for Suspend-to-RAM on AM33xx and AM43xx SoCs. Also needed
+	  for deep CPUIdle states on AM33xx SoCs. Allows for loading of the
+	  firmware onto these remote processors.
+	  If unsure say N.
+
 config DA8XX_REMOTEPROC
 	tristate "DA8xx/OMAP-L13x remoteproc support"
 	depends on ARCH_DAVINCI_DA8XX

drivers/remoteproc/Makefile

···
 remoteproc-y				+= remoteproc_elf_loader.o
 obj-$(CONFIG_OMAP_REMOTEPROC)		+= omap_remoteproc.o
 obj-$(CONFIG_STE_MODEM_RPROC)	 	+= ste_modem_rproc.o
+obj-$(CONFIG_WKUP_M3_RPROC)		+= wkup_m3_rproc.o
 obj-$(CONFIG_DA8XX_REMOTEPROC)		+= da8xx_remoteproc.o

drivers/remoteproc/wkup_m3_rproc.c

···
+/*
+ * TI AMx3 Wakeup M3 Remote Processor driver
+ *
+ * Copyright (C) 2014-2015 Texas Instruments, Inc.
+ *
+ * Dave Gerlach <[e-mail]>
+ * Suman Anna <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/remoteproc.h>
+
+#include <linux/platform_data/wkup_m3.h>
+
+#include "remoteproc_internal.h"
+
+#define WKUPM3_MEM_MAX	2
+
+/**
+ * struct wkup_m3_mem - WkupM3 internal memory structure
+ * @cpu_addr: MPU virtual address of the memory region
+ * @bus_addr: Bus address used to access the memory region
+ * @dev_addr: Device address from Wakeup M3 view
+ * @size: Size of the memory region
+ */
+struct wkup_m3_mem {
+	void __iomem *cpu_addr;
+	phys_addr_t bus_addr;
+	u32 dev_addr;
+	size_t size;
+};
+
+/**
+ * struct wkup_m3_rproc - WkupM3 remote processor state
+ * @rproc: rproc handle
+ * @pdev: pointer to platform device
+ * @mem: WkupM3 memory information
+ */
+struct wkup_m3_rproc {
+	struct rproc *rproc;
+	struct platform_device *pdev;
+	struct wkup_m3_mem mem[WKUPM3_MEM_MAX];
+};
+
+static int wkup_m3_rproc_start(struct rproc *rproc)
+{
+	struct wkup_m3_rproc *wkupm3 = rproc->priv;
+	struct platform_device *pdev = wkupm3->pdev;
+	struct device *dev = &pdev->dev;
+	struct wkup_m3_platform_data *pdata = dev_get_platdata(dev);
+
+	if (pdata->deassert_reset(pdev, pdata->reset_name)) {
+		dev_err(dev, "Unable to reset wkup_m3!\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int wkup_m3_rproc_stop(struct rproc *rproc)
+{
+	struct wkup_m3_rproc *wkupm3 = rproc->priv;
+	struct platform_device *pdev = wkupm3->pdev;
+	struct device *dev = &pdev->dev;
+	struct wkup_m3_platform_data *pdata = dev_get_platdata(dev);
+
+	if (pdata->assert_reset(pdev, pdata->reset_name)) {
+		dev_err(dev, "Unable to assert reset of wkup_m3!\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static void *wkup_m3_rproc_da_to_va(struct rproc *rproc, u64 da, int len)
+{
+	struct wkup_m3_rproc *wkupm3 = rproc->priv;
+	void *va = NULL;
+	int i;
+	u32 offset;
+
+	if (len <= 0)
+		return NULL;
+
+	for (i = 0; i < WKUPM3_MEM_MAX; i++) {
+		if (da >= wkupm3->mem[i].dev_addr && da + len <=
+		    wkupm3->mem[i].dev_addr +  wkupm3->mem[i].size) {
+			offset = da -  wkupm3->mem[i].dev_addr;
+			/* __force to make sparse happy with type conversion */
+			va = (__force void *)(wkupm3->mem[i].cpu_addr + offset);
+			break;
+		}
+	}
+
+	return va;
+}
+
+static struct rproc_ops wkup_m3_rproc_ops = {
+	.start		= wkup_m3_rproc_start,
+	.stop		= wkup_m3_rproc_stop,
+	.da_to_va	= wkup_m3_rproc_da_to_va,
+};
+
+static const struct of_device_id wkup_m3_rproc_of_match[] = {
+	{ .compatible = "ti,am3352-wkup-m3", },
+	{ .compatible = "ti,am4372-wkup-m3", },
+	{},
+};
+
+static int wkup_m3_rproc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct wkup_m3_platform_data *pdata = dev->platform_data;
+	/* umem always needs to be processed first */
+	const char *mem_names[WKUPM3_MEM_MAX] = { "umem", "dmem" };
+	struct wkup_m3_rproc *wkupm3;
+	const char *fw_name;
+	struct rproc *rproc;
+	struct resource *res;
+	const __be32 *addrp;
+	u32 l4_offset = 0;
+	u64 size;
+	int ret;
+	int i;
+
+	if (!(pdata && pdata->deassert_reset && pdata->assert_reset &&
+	      pdata->reset_name)) {
+		dev_err(dev, "Platform data missing!\n");
+		return -ENODEV;
+	}
+
+	ret = of_property_read_string(dev->of_node, "ti,pm-firmware",
+				      &fw_name);
+	if (ret) {
+		dev_err(dev, "No firmware filename given\n");
+		return -ENODEV;
+	}
+
+	pm_runtime_enable(&pdev->dev);
+	ret = pm_runtime_get_sync(&pdev->dev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "pm_runtime_get_sync() failed\n");
+		goto err;
+	}
+
+	rproc = rproc_alloc(dev, "wkup_m3", &wkup_m3_rproc_ops,
+			    fw_name, sizeof(*wkupm3));
+	if (!rproc) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	wkupm3 = rproc->priv;
+	wkupm3->rproc = rproc;
+	wkupm3->pdev = pdev;
+
+	for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
+		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+						   mem_names[i]);
+		wkupm3->mem[i].cpu_addr = devm_ioremap_resource(dev, res);
+		if (IS_ERR(wkupm3->mem[i].cpu_addr)) {
+			dev_err(&pdev->dev, "devm_ioremap_resource failed for resource %d\n",
+				i);
+			ret = PTR_ERR(wkupm3->mem[i].cpu_addr);
+			goto err;
+		}
+		wkupm3->mem[i].bus_addr = res->start;
+		wkupm3->mem[i].size = resource_size(res);
+		addrp = of_get_address(dev->of_node, i, &size, NULL);
+		/*
+		 * The wkupm3 has umem at address 0 in its view, so the device
+		 * addresses for each memory region is computed as a relative
+		 * offset of the bus address for umem, and therefore needs to be
+		 * processed first.
+		 */
+		if (!strcmp(mem_names[i], "umem"))
+			l4_offset = be32_to_cpu(*addrp);
+		wkupm3->mem[i].dev_addr = be32_to_cpu(*addrp) - l4_offset;
+	}
+
+	dev_set_drvdata(dev, rproc);
+
+	ret = rproc_add(rproc);
+	if (ret) {
+		dev_err(dev, "rproc_add failed\n");
+		goto err_put_rproc;
+	}
+
+	return 0;
+
+err_put_rproc:
+	rproc_put(rproc);
+err:
+	pm_runtime_put_noidle(dev);
+	pm_runtime_disable(dev);
+	return ret;
+}
+
+static int wkup_m3_rproc_remove(struct platform_device *pdev)
+{
+	struct rproc *rproc = platform_get_drvdata(pdev);
+
+	rproc_del(rproc);
+	rproc_put(rproc);
+	pm_runtime_put_sync(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int wkup_m3_rpm_suspend(struct device *dev)
+{
+	return -EBUSY;
+}
+
+static int wkup_m3_rpm_resume(struct device *dev)
+{
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops wkup_m3_rproc_pm_ops = {
+	SET_RUNTIME_PM_OPS(wkup_m3_rpm_suspend, wkup_m3_rpm_resume, NULL)
+};
+
+static struct platform_driver wkup_m3_rproc_driver = {
+	.probe = wkup_m3_rproc_probe,
+	.remove = wkup_m3_rproc_remove,
+	.driver = {
+		.name = "wkup_m3_rproc",
+		.of_match_table = wkup_m3_rproc_of_match,
+		.pm = &wkup_m3_rproc_pm_ops,
+	},
+};
+
+module_platform_driver(wkup_m3_rproc_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("TI Wakeup M3 remote processor control driver");
+MODULE_AUTHOR("Dave Gerlach <[e-mail]>");

include/linux/platform_data/wkup_m3.h

···
+/*
+ * TI Wakeup M3 remote processor platform data
+ *
+ * Copyright (C) 2014-2015 Texas Instruments, Inc.
+ *
+ * Dave Gerlach <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _LINUX_PLATFORM_DATA_WKUP_M3_H
+#define _LINUX_PLATFORM_DATA_WKUP_M3_H
+
+struct platform_device;
+
+struct wkup_m3_platform_data {
+	const char *reset_name;
+
+	int (*assert_reset)(struct platform_device *pdev, const char *name);
+	int (*deassert_reset)(struct platform_device *pdev, const char *name);
+};
+
+#endif /* _LINUX_PLATFORM_DATA_WKUP_M3_H */