drivers: Introduce a simplified remoteproc framework

Many System on Chip(SoC) solutions are complex with multiple processors
on the same die dedicated to either general purpose of specialized
functions. Many examples do exist in today's SoCs from various vendors.
Typical examples are micro controllers such as an ARM M3/M0 doing a
offload of specific function such as event integration or power
management or controlling camera etc.

Traditionally, the responsibility of loading up such a processor with a
firmware and communication has been with a High Level Operating
System(HLOS) such as Linux. However, there exists classes of products
where Linux would need to expect services from such a processor or the
delay of Linux and operating system being able to load up such a
firmware is unacceptable.

To address these needs, we need some minimal capability to load such a
system and ensure it is started prior to an Operating System(Linux or
any other) is started up.

NOTE: This is NOT meant to be a solve-all solution, instead, it tries to
address certain class of SoCs and products that need such a solution.

A very simple model is introduced here as part of the initial support
that supports microcontrollers with internal memory (no MMU, no
execution from external memory, or specific image format needs). This
basic framework can then (hopefully) be extensible to other complex SoC
processor support as need be.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Simon Glass <sjg@chromium.org>

3 files changed, 439 insertions, 0 deletions

diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
new file mode 100644
index 00000000000..444682624ac
--- /dev/null
+++ b/drivers/remoteproc/Kconfig
@@ -0,0 +1,15 @@
+#
+# (C) Copyright 2015
+# Texas Instruments Incorporated - http://www.ti.com/
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+menu "Remote Processor drivers"
+
+# REMOTEPROC gets selected by drivers as needed
+# All users should depend on DM
+config REMOTEPROC
+	bool
+	depends on DM
+
+endmenu
diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
new file mode 100644
index 00000000000..14c27929b63
--- /dev/null
+++ b/drivers/remoteproc/Makefile
@@ -0,0 +1,7 @@
+#
+# (C) Copyright 2015
+# Texas Instruments Incorporated - http://www.ti.com/
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-$(CONFIG_REMOTEPROC) += rproc-uclass.o
diff --git a/drivers/remoteproc/rproc-uclass.c b/drivers/remoteproc/rproc-uclass.c
new file mode 100644
index 00000000000..a421e12e5d1
--- /dev/null
+++ b/drivers/remoteproc/rproc-uclass.c
@@ -0,0 +1,417 @@
+/*
+ * (C) Copyright 2015
+ * Texas Instruments Incorporated - http://www.ti.com/
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+#define pr_fmt(fmt) "%s: " fmt, __func__
+#include <common.h>
+#include <errno.h>
+#include <fdtdec.h>
+#include <malloc.h>
+#include <remoteproc.h>
+#include <asm/io.h>
+#include <dm/device-internal.h>
+#include <dm.h>
+#include <dm/uclass.h>
+#include <dm/uclass-internal.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/**
+ * for_each_remoteproc_device() - iterate through the list of rproc devices
+ * @fn: check function to call per match, if this function returns fail,
+ *	iteration is aborted with the resultant error value
+ * @skip_dev:	Device to skip calling the callback about.
+ * @data:	Data to pass to the callback function
+ *
+ * Return: 0 if none of the callback returned a non 0 result, else returns the
+ * result from the callback function
+ */
+static int for_each_remoteproc_device(int (*fn) (struct udevice *dev,
+					struct dm_rproc_uclass_pdata *uc_pdata,
+					const void *data),
+				      struct udevice *skip_dev,
+				      const void *data)
+{
+	struct udevice *dev;
+	struct dm_rproc_uclass_pdata *uc_pdata;
+	int ret;
+
+	for (ret = uclass_find_first_device(UCLASS_REMOTEPROC, &dev); dev;
+	     ret = uclass_find_next_device(&dev)) {
+		if (ret || dev == skip_dev)
+			continue;
+		uc_pdata = dev_get_uclass_platdata(dev);
+		ret = fn(dev, uc_pdata, data);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * _rproc_name_is_unique() - iteration helper to check if rproc name is unique
+ * @dev:	device that we are checking name for
+ * @uc_pdata:	uclass platform data
+ * @data:	compare data (this is the name we want to ensure is unique)
+ *
+ * Return: 0 is there is no match(is unique); if there is a match(we dont
+ * have a unique name), return -EINVAL.
+ */
+static int _rproc_name_is_unique(struct udevice *dev,
+				 struct dm_rproc_uclass_pdata *uc_pdata,
+				 const void *data)
+{
+	const char *check_name = data;
+
+	/* devices not yet populated with data - so skip them */
+	if (!uc_pdata->name && check_name)
+		return 0;
+
+	/* Return 0 to search further if we dont match */
+	if (strlen(uc_pdata->name) != strlen(check_name))
+		return 0;
+
+	if (!strcmp(uc_pdata->name, check_name))
+		return -EINVAL;
+
+	return 0;
+}
+
+/**
+ * rproc_name_is_unique() - Check if the rproc name is unique
+ * @check_dev:	Device we are attempting to ensure is unique
+ * @check_name:	Name we are trying to ensure is unique.
+ *
+ * Return: true if we have a unique name, false if name is not unique.
+ */
+static bool rproc_name_is_unique(struct udevice *check_dev,
+				 const char *check_name)
+{
+	int ret;
+
+	ret = for_each_remoteproc_device(_rproc_name_is_unique,
+					 check_dev, check_name);
+	return ret ? false : true;
+}
+
+/**
+ * rproc_pre_probe() - Pre probe accessor for the uclass
+ * @dev:	device for which we are preprobing
+ *
+ * Parses and fills up the uclass pdata for use as needed by core and
+ * remote proc drivers.
+ *
+ * Return: 0 if all wernt ok, else appropriate error value.
+ */
+static int rproc_pre_probe(struct udevice *dev)
+{
+	struct dm_rproc_uclass_pdata *uc_pdata;
+	const struct dm_rproc_ops *ops;
+
+	uc_pdata = dev_get_uclass_platdata(dev);
+
+	/* See if we need to populate via fdt */
+
+	if (!dev->platdata) {
+#if CONFIG_IS_ENABLED(OF_CONTROL)
+		int node = dev->of_offset;
+		const void *blob = gd->fdt_blob;
+		bool tmp;
+		if (!blob) {
+			debug("'%s' no dt?\n", dev->name);
+			return -EINVAL;
+		}
+		debug("'%s': using fdt\n", dev->name);
+		uc_pdata->name = fdt_getprop(blob, node,
+					     "remoteproc-name", NULL);
+
+		/* Default is internal memory mapped */
+		uc_pdata->mem_type = RPROC_INTERNAL_MEMORY_MAPPED;
+		tmp = fdtdec_get_bool(blob, node,
+				      "remoteproc-internal-memory-mapped");
+		if (tmp)
+			uc_pdata->mem_type = RPROC_INTERNAL_MEMORY_MAPPED;
+#else
+		/* Nothing much we can do about this, can we? */
+		return -EINVAL;
+#endif
+
+	} else {
+		struct dm_rproc_uclass_pdata *pdata = dev->platdata;
+
+		debug("'%s': using legacy data\n", dev->name);
+		if (pdata->name)
+			uc_pdata->name = pdata->name;
+		uc_pdata->mem_type = pdata->mem_type;
+		uc_pdata->driver_plat_data = pdata->driver_plat_data;
+	}
+
+	/* Else try using device Name */
+	if (!uc_pdata->name)
+		uc_pdata->name = dev->name;
+	if (!uc_pdata->name) {
+		debug("Unnamed device!");
+		return -EINVAL;
+	}
+
+	if (!rproc_name_is_unique(dev, uc_pdata->name)) {
+		debug("%s duplicate name '%s'\n", dev->name, uc_pdata->name);
+		return -EINVAL;
+	}
+
+	ops = rproc_get_ops(dev);
+	if (!ops) {
+		debug("%s driver has no ops?\n", dev->name);
+		return -EINVAL;
+	}
+
+	if (!ops->load || !ops->start) {
+		debug("%s driver has missing mandatory ops?\n", dev->name);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * rproc_post_probe() - post probe accessor for the uclass
+ * @dev:	deivce we finished probing
+ *
+ * initiate init function after the probe is completed. This allows
+ * the remote processor drivers to split up the initializations between
+ * probe and init as needed.
+ *
+ * Return: if the remote proc driver has a init routine, invokes it and
+ * hands over the return value. overall, 0 if all went well, else appropriate
+ * error value.
+ */
+static int rproc_post_probe(struct udevice *dev)
+{
+	const struct dm_rproc_ops *ops;
+
+	ops = rproc_get_ops(dev);
+	if (!ops) {
+		debug("%s driver has no ops?\n", dev->name);
+		return -EINVAL;
+	}
+
+	if (ops->init)
+		return ops->init(dev);
+
+	return 0;
+}
+
+UCLASS_DRIVER(rproc) = {
+	.id = UCLASS_REMOTEPROC,
+	.name = "remoteproc",
+	.flags = DM_UC_FLAG_SEQ_ALIAS,
+	.pre_probe = rproc_pre_probe,
+	.post_probe = rproc_post_probe,
+	.per_device_platdata_auto_alloc_size =
+		sizeof(struct dm_rproc_uclass_pdata),
+};
+
+/* Remoteproc subsystem access functions */
+/**
+ * _rproc_probe_dev() - iteration helper to probe a rproc device
+ * @dev:	device to probe
+ * @uc_pdata:	uclass data allocated for the device
+ * @data:	unused
+ *
+ * Return: 0 if all ok, else appropriate error value.
+ */
+static int _rproc_probe_dev(struct udevice *dev,
+			    struct dm_rproc_uclass_pdata *uc_pdata,
+			    const void *data)
+{
+	int ret;
+
+	ret = device_probe(dev);
+
+	if (ret)
+		debug("%s: Failed to initialize - %d\n", dev->name, ret);
+	return ret;
+}
+
+/**
+ * _rproc_dev_is_probed() - check if the device has been probed
+ * @dev:	device to check
+ * @uc_pdata:	unused
+ * @data:	unused
+ *
+ * Return: -EAGAIN if not probed else return 0
+ */
+static int _rproc_dev_is_probed(struct udevice *dev,
+			    struct dm_rproc_uclass_pdata *uc_pdata,
+			    const void *data)
+{
+	if (dev->flags & DM_FLAG_ACTIVATED)
+		return 0;
+
+	return -EAGAIN;
+}
+
+bool rproc_is_initialized(void)
+{
+	int ret = for_each_remoteproc_device(_rproc_dev_is_probed, NULL, NULL);
+	return ret ? false : true;
+}
+
+int rproc_init(void)
+{
+	int ret;
+
+	if (rproc_is_initialized()) {
+		debug("Already initialized\n");
+		return -EINVAL;
+	}
+
+	ret = for_each_remoteproc_device(_rproc_probe_dev, NULL, NULL);
+	return ret;
+}
+
+int rproc_load(int id, ulong addr, ulong size)
+{
+	struct udevice *dev = NULL;
+	struct dm_rproc_uclass_pdata *uc_pdata;
+	const struct dm_rproc_ops *ops;
+	int ret;
+
+	ret = uclass_get_device_by_seq(UCLASS_REMOTEPROC, id, &dev);
+	if (ret) {
+		debug("Unknown remote processor id '%d' requested(%d)\n",
+		      id, ret);
+		return ret;
+	}
+
+	uc_pdata = dev_get_uclass_platdata(dev);
+
+	ops = rproc_get_ops(dev);
+	if (!ops) {
+		debug("%s driver has no ops?\n", dev->name);
+		return -EINVAL;
+	}
+
+	debug("Loading to '%s' from address 0x%08lX size of %lu bytes\n",
+	      uc_pdata->name, addr, size);
+	if (ops->load)
+		return ops->load(dev, addr, size);
+
+	debug("%s: data corruption?? mandatory function is missing!\n",
+	      dev->name);
+
+	return -EINVAL;
+};
+
+/*
+ * Completely internal helper enums..
+ * Keeping this isolated helps this code evolve independent of other
+ * parts..
+ */
+enum rproc_ops {
+	RPROC_START,
+	RPROC_STOP,
+	RPROC_RESET,
+	RPROC_PING,
+	RPROC_RUNNING,
+};
+
+/**
+ * _rproc_ops_wrapper() - wrapper for invoking remote proc driver callback
+ * @id:		id of the remote processor
+ * @op:		one of rproc_ops that indicate what operation to invoke
+ *
+ * Most of the checks and verification for remoteproc operations are more
+ * or less same for almost all operations. This allows us to put a wrapper
+ * and use the common checks to allow the driver to function appropriately.
+ *
+ * Return: 0 if all ok, else appropriate error value.
+ */
+static int _rproc_ops_wrapper(int id, enum rproc_ops op)
+{
+	struct udevice *dev = NULL;
+	struct dm_rproc_uclass_pdata *uc_pdata;
+	const struct dm_rproc_ops *ops;
+	int (*fn)(struct udevice *dev);
+	bool mandatory = false;
+	char *op_str;
+	int ret;
+
+	ret = uclass_get_device_by_seq(UCLASS_REMOTEPROC, id, &dev);
+	if (ret) {
+		debug("Unknown remote processor id '%d' requested(%d)\n",
+		      id, ret);
+		return ret;
+	}
+
+	uc_pdata = dev_get_uclass_platdata(dev);
+
+	ops = rproc_get_ops(dev);
+	if (!ops) {
+		debug("%s driver has no ops?\n", dev->name);
+		return -EINVAL;
+	}
+	switch (op) {
+	case RPROC_START:
+		fn = ops->start;
+		mandatory = true;
+		op_str = "Starting";
+		break;
+	case RPROC_STOP:
+		fn = ops->stop;
+		op_str = "Stopping";
+		break;
+	case RPROC_RESET:
+		fn = ops->reset;
+		op_str = "Resetting";
+		break;
+	case RPROC_RUNNING:
+		fn = ops->is_running;
+		op_str = "Checking if running:";
+		break;
+	case RPROC_PING:
+		fn = ops->ping;
+		op_str = "Pinging";
+		break;
+	default:
+		debug("what is '%d' operation??\n", op);
+		return -EINVAL;
+	}
+
+	debug("%s %s...\n", op_str, uc_pdata->name);
+	if (fn)
+		return fn(dev);
+
+	if (mandatory)
+		debug("%s: data corruption?? mandatory function is missing!\n",
+		      dev->name);
+
+	return -ENOSYS;
+}
+
+int rproc_start(int id)
+{
+	return _rproc_ops_wrapper(id, RPROC_START);
+};
+
+int rproc_stop(int id)
+{
+	return _rproc_ops_wrapper(id, RPROC_STOP);
+};
+
+int rproc_reset(int id)
+{
+	return _rproc_ops_wrapper(id, RPROC_RESET);
+};
+
+int rproc_ping(int id)
+{
+	return _rproc_ops_wrapper(id, RPROC_PING);
+};
+
+int rproc_is_running(int id)
+{
+	return _rproc_ops_wrapper(id, RPROC_RUNNING);
+};