remoteproc: Add STE modem driver

Add support for the STE modem shared memory driver.
This driver hooks into the remoteproc framework
in order to manage configuration and the virtio
devices.

This driver adds custom firmware handlers, because
STE modem uses a custom firmware layout.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
cc: Linus Walleij <linus.walleij@linaro.org>
cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
[ohad: validate mdev->ops, move setup() to probe/remove, trivial style changes]
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

3 files changed, 334 insertions, 0 deletions

diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
index b4d8de56b52e..a1024d9569ca 100644
--- a/drivers/remoteproc/Kconfig
+++ b/drivers/remoteproc/Kconfig
@@ -29,4 +29,15 @@ config OMAP_REMOTEPROC
 	  It's safe to say n here if you're not interested in multimedia
 	  offloading or just want a bare minimum kernel.
 
+config STE_MODEM_RPROC
+	tristate "STE-Modem remoteproc support"
+	depends on EXPERIMENTAL
+	depends on HAS_DMA
+	select REMOTEPROC
+	default n
+	help
+	  Say y or m here to support STE-Modem shared memory driver.
+	  This can be either built-in or a loadable module.
+	  If unsure say N.
+
 endmenu
diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
index 934ce6e2c66b..391b65181c05 100644
--- a/drivers/remoteproc/Makefile
+++ b/drivers/remoteproc/Makefile
@@ -8,3 +8,4 @@ remoteproc-y				+= remoteproc_debugfs.o
 remoteproc-y				+= remoteproc_virtio.o
 remoteproc-y				+= remoteproc_elf_loader.o
 obj-$(CONFIG_OMAP_REMOTEPROC)		+= omap_remoteproc.o
+obj-$(CONFIG_STE_MODEM_RPROC)	 	+= ste_modem_rproc.o
diff --git a/drivers/remoteproc/ste_modem_rproc.c b/drivers/remoteproc/ste_modem_rproc.c
new file mode 100644
index 000000000000..a7743c069339
--- /dev/null
+++ b/drivers/remoteproc/ste_modem_rproc.c
@@ -0,0 +1,322 @@
+/*
+ * Copyright (C) ST-Ericsson AB 2012
+ * Author: Sjur Brændeland <sjur.brandeland@stericsson.com>
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#include <linux/module.h>
+#include <linux/dma-mapping.h>
+#include <linux/remoteproc.h>
+#include <linux/ste_modem_shm.h>
+#include "remoteproc_internal.h"
+
+#define SPROC_FW_SIZE (50 * 4096)
+#define SPROC_MAX_TOC_ENTRIES 32
+#define SPROC_MAX_NOTIFY_ID 14
+#define SPROC_RESOURCE_NAME "rsc-table"
+#define SPROC_MODEM_NAME "ste-modem"
+#define SPROC_MODEM_FIRMWARE SPROC_MODEM_NAME "-fw.bin"
+
+#define sproc_dbg(sproc, fmt, ...) \
+	dev_dbg(&sproc->mdev->pdev.dev, fmt, ##__VA_ARGS__)
+#define sproc_err(sproc, fmt, ...) \
+	dev_err(&sproc->mdev->pdev.dev, fmt, ##__VA_ARGS__)
+
+/* STE-modem control structure */
+struct sproc {
+	struct rproc *rproc;
+	struct ste_modem_device *mdev;
+	int error;
+	void *fw_addr;
+	size_t fw_size;
+	dma_addr_t fw_dma_addr;
+};
+
+/* STE-Modem firmware entry */
+struct ste_toc_entry {
+	__le32 start;
+	__le32 size;
+	__le32 flags;
+	__le32 entry_point;
+	__le32 load_addr;
+	char name[12];
+};
+
+/*
+ * The Table Of Content is located at the start of the firmware image and
+ * at offset zero in the shared memory region. The resource table typically
+ * contains the initial boot image (boot strap) and other information elements
+ * such as remoteproc resource table. Each entry is identified by a unique
+ * name.
+ */
+struct ste_toc {
+	struct ste_toc_entry table[SPROC_MAX_TOC_ENTRIES];
+};
+
+/* Loads the firmware to shared memory. */
+static int sproc_load_segments(struct rproc *rproc, const struct firmware *fw)
+{
+	struct sproc *sproc = rproc->priv;
+
+	memcpy(sproc->fw_addr, fw->data, fw->size);
+
+	return 0;
+}
+
+/* Find the entry for resource table in the Table of Content */
+static struct ste_toc_entry *sproc_find_rsc_entry(const struct firmware *fw)
+{
+	int i;
+	struct ste_toc *toc;
+
+	if (!fw)
+		return NULL;
+
+	toc = (void *)fw->data;
+
+	/* Search the table for the resource table */
+	for (i = 0; i < SPROC_MAX_TOC_ENTRIES &&
+		    toc->table[i].start != 0xffffffff; i++) {
+
+		if (!strncmp(toc->table[i].name, SPROC_RESOURCE_NAME,
+			     sizeof(toc->table[i].name))) {
+			if (toc->table[i].start > fw->size)
+				return NULL;
+			return &toc->table[i];
+		}
+	}
+
+	return NULL;
+}
+
+/* Find the resource table inside the remote processor's firmware. */
+static struct resource_table *
+sproc_find_rsc_table(struct rproc *rproc, const struct firmware *fw,
+		     int *tablesz)
+{
+	struct sproc *sproc = rproc->priv;
+	struct resource_table *table;
+	struct ste_toc_entry *entry;
+
+	entry = sproc_find_rsc_entry(fw);
+	if (!entry) {
+		sproc_err(sproc, "resource table not found in fw\n");
+		return NULL;
+	}
+
+	table = (void *)(fw->data + entry->start);
+
+	/* sanity check size and offset of resource table */
+	if (entry->start > SPROC_FW_SIZE ||
+	    entry->size > SPROC_FW_SIZE ||
+	    fw->size > SPROC_FW_SIZE ||
+	    entry->start + entry->size > fw->size ||
+	    sizeof(struct resource_table) > entry->size) {
+		sproc_err(sproc, "bad size of fw or resource table\n");
+		return NULL;
+	}
+
+	/* we don't support any version beyond the first */
+	if (table->ver != 1) {
+		sproc_err(sproc, "unsupported fw ver: %d\n", table->ver);
+		return NULL;
+	}
+
+	/* make sure reserved bytes are zeroes */
+	if (table->reserved[0] || table->reserved[1]) {
+		sproc_err(sproc, "non zero reserved bytes\n");
+		return NULL;
+	}
+
+	/* make sure the offsets array isn't truncated */
+	if (table->num > SPROC_MAX_TOC_ENTRIES ||
+	    table->num * sizeof(table->offset[0]) +
+	    sizeof(struct resource_table) > entry->size) {
+		sproc_err(sproc, "resource table incomplete\n");
+		return NULL;
+	}
+
+	/* If the fw size has grown, release the previous fw allocation */
+	if (SPROC_FW_SIZE < fw->size) {
+		sproc_err(sproc, "Insufficient space for fw (%d < %zd)\n",
+			  SPROC_FW_SIZE, fw->size);
+		return NULL;
+	}
+
+	sproc->fw_size = fw->size;
+	*tablesz = entry->size;
+
+	return table;
+}
+
+/* STE modem firmware handler operations */
+const struct rproc_fw_ops sproc_fw_ops = {
+	.load = sproc_load_segments,
+	.find_rsc_table = sproc_find_rsc_table,
+};
+
+/* Kick the modem with specified notification id */
+static void sproc_kick(struct rproc *rproc, int vqid)
+{
+	struct sproc *sproc = rproc->priv;
+
+	sproc_dbg(sproc, "kick vqid:%d\n", vqid);
+
+	/*
+	 * We need different notification IDs for RX and TX so add
+	 * an offset on TX notification IDs.
+	 */
+	sproc->mdev->ops.kick(sproc->mdev, vqid + SPROC_MAX_NOTIFY_ID);
+}
+
+/* Received a kick from a modem, kick the virtqueue */
+static void sproc_kick_callback(struct ste_modem_device *mdev, int vqid)
+{
+	struct sproc *sproc = mdev->drv_data;
+
+	if (rproc_vq_interrupt(sproc->rproc, vqid) == IRQ_NONE)
+		sproc_dbg(sproc, "no message was found in vqid %d\n", vqid);
+}
+
+struct ste_modem_dev_cb sproc_dev_cb = {
+	.kick = sproc_kick_callback,
+};
+
+/* Start the STE modem */
+static int sproc_start(struct rproc *rproc)
+{
+	struct sproc *sproc = rproc->priv;
+	int i, err;
+
+	sproc_dbg(sproc, "start ste-modem\n");
+
+	/* Sanity test the max_notifyid */
+	if (rproc->max_notifyid > SPROC_MAX_NOTIFY_ID) {
+		sproc_err(sproc, "Notification IDs too high:%d\n",
+			  rproc->max_notifyid);
+		return -EINVAL;
+	}
+
+	/* Subscribe to notifications */
+	for (i = 0; i < rproc->max_notifyid; i++) {
+		err = sproc->mdev->ops.kick_subscribe(sproc->mdev, i);
+		if (err) {
+			sproc_err(sproc,
+				  "subscription of kicks failed:%d\n", err);
+			return err;
+		}
+	}
+
+	/* Request modem start-up*/
+	return sproc->mdev->ops.power(sproc->mdev, true);
+}
+
+/* Stop the STE modem */
+static int sproc_stop(struct rproc *rproc)
+{
+	struct sproc *sproc = rproc->priv;
+	sproc_dbg(sproc, "stop ste-modem\n");
+
+	return sproc->mdev->ops.power(sproc->mdev, false);
+}
+
+static struct rproc_ops sproc_ops = {
+	.start		= sproc_start,
+	.stop		= sproc_stop,
+	.kick		= sproc_kick,
+};
+
+/* STE modem device is unregistered */
+static int sproc_drv_remove(struct platform_device *pdev)
+{
+	struct ste_modem_device *mdev =
+		container_of(pdev, struct ste_modem_device, pdev);
+	struct sproc *sproc = mdev->drv_data;
+
+	sproc_dbg(sproc, "remove ste-modem\n");
+
+	/* Reset device callback functions */
+	sproc->mdev->ops.setup(sproc->mdev, NULL);
+
+	/* Unregister as remoteproc device */
+	rproc_del(sproc->rproc);
+	rproc_put(sproc->rproc);
+
+	mdev->drv_data = NULL;
+
+	return 0;
+}
+
+/* Handle probe of a modem device */
+static int sproc_probe(struct platform_device *pdev)
+{
+	struct ste_modem_device *mdev =
+		container_of(pdev, struct ste_modem_device, pdev);
+	struct sproc *sproc;
+	struct rproc *rproc;
+	int err;
+
+	dev_dbg(&mdev->pdev.dev, "probe ste-modem\n");
+
+	if (!mdev->ops.setup || !mdev->ops.kick || !mdev->ops.kick_subscribe ||
+	    !mdev->ops.power) {
+		dev_err(&mdev->pdev.dev, "invalid mdev ops\n");
+		return -EINVAL;
+	}
+
+	rproc = rproc_alloc(&mdev->pdev.dev, mdev->pdev.name, &sproc_ops,
+			    SPROC_MODEM_FIRMWARE, sizeof(*sproc));
+	if (!rproc)
+		return -ENOMEM;
+
+	sproc = rproc->priv;
+	sproc->mdev = mdev;
+	sproc->rproc = rproc;
+	mdev->drv_data = sproc;
+
+	/* Provide callback functions to modem device */
+	sproc->mdev->ops.setup(sproc->mdev, &sproc_dev_cb);
+
+	/* Set the STE-modem specific firmware handler */
+	rproc->fw_ops = &sproc_fw_ops;
+
+	/*
+	 * STE-modem requires the firmware to be located
+	 * at the start of the shared memory region. So we need to
+	 * reserve space for firmware at the start.
+	 */
+	sproc->fw_addr = dma_alloc_coherent(rproc->dev.parent, SPROC_FW_SIZE,
+					    &sproc->fw_dma_addr,
+					    GFP_KERNEL);
+	if (!sproc->fw_addr) {
+		sproc_err(sproc, "Cannot allocate memory for fw\n");
+		err = -ENOMEM;
+		goto free_rproc;
+	}
+
+	/* Register as a remoteproc device */
+	err = rproc_add(rproc);
+	if (err)
+		goto free_rproc;
+
+	return 0;
+
+free_rproc:
+	/* Reset device data upon error */
+	mdev->drv_data = NULL;
+	rproc_put(rproc);
+	return err;
+}
+
+static struct platform_driver sproc_driver = {
+	.driver	= {
+		.name	= SPROC_MODEM_NAME,
+		.owner	= THIS_MODULE,
+	},
+	.probe	= sproc_probe,
+	.remove	= sproc_drv_remove,
+};
+
+module_platform_driver(sproc_driver);
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("STE Modem driver using the Remote Processor Framework");