ARM: 6415/1: ux500: DB5500 mailbox driver

This is a driver for the mailboxes used to communicate with the
DB5500 modem portions.

Signed-off-by: Stefan Nilsson XK <stefan.xk.nilsson@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 567 insertions, 0 deletions

diff --git a/arch/arm/mach-ux500/mbox.c b/arch/arm/mach-ux500/mbox.c
new file mode 100644
index 00000000000..63435389c54
--- /dev/null
+++ b/arch/arm/mach-ux500/mbox.c
@@ -0,0 +1,567 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2010
+ * Author: Stefan Nilsson <stefan.xk.nilsson@stericsson.com> for ST-Ericsson.
+ * Author: Martin Persson <martin.persson@stericsson.com> for ST-Ericsson.
+ * License terms: GNU General Public License (GPL), version 2.
+ */
+
+/*
+ * Mailbox nomenclature:
+ *
+ *       APE           MODEM
+ *           mbox pairX
+ *   ..........................
+ *   .                       .
+ *   .           peer        .
+ *   .     send  ----        .
+ *   .      -->  |  |        .
+ *   .           |  |        .
+ *   .           ----        .
+ *   .                       .
+ *   .           local       .
+ *   .     rec   ----        .
+ *   .           |  | <--    .
+ *   .           |  |        .
+ *   .           ----        .
+ *   .........................
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/platform_device.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/completion.h>
+#include <mach/mbox.h>
+
+#define MBOX_NAME "mbox"
+
+#define MBOX_FIFO_DATA        0x000
+#define MBOX_FIFO_ADD         0x004
+#define MBOX_FIFO_REMOVE      0x008
+#define MBOX_FIFO_THRES_FREE  0x00C
+#define MBOX_FIFO_THRES_OCCUP 0x010
+#define MBOX_FIFO_STATUS      0x014
+
+#define MBOX_DISABLE_IRQ 0x4
+#define MBOX_ENABLE_IRQ  0x0
+#define MBOX_LATCH 1
+
+/* Global list of all mailboxes */
+static struct list_head mboxs = LIST_HEAD_INIT(mboxs);
+
+static struct mbox *get_mbox_with_id(u8 id)
+{
+	u8 i;
+	struct list_head *pos = &mboxs;
+	for (i = 0; i <= id; i++)
+		pos = pos->next;
+
+	return (struct mbox *) list_entry(pos, struct mbox, list);
+}
+
+int mbox_send(struct mbox *mbox, u32 mbox_msg, bool block)
+{
+	int res = 0;
+
+	spin_lock(&mbox->lock);
+
+	dev_dbg(&(mbox->pdev->dev),
+		"About to buffer 0x%X to mailbox 0x%X."
+		" ri = %d, wi = %d\n",
+		mbox_msg, (u32)mbox, mbox->read_index,
+		mbox->write_index);
+
+	/* Check if write buffer is full */
+	while (((mbox->write_index + 1) % MBOX_BUF_SIZE) == mbox->read_index) {
+		if (!block) {
+			dev_dbg(&(mbox->pdev->dev),
+			"Buffer full in non-blocking call! "
+			"Returning -ENOMEM!\n");
+			res = -ENOMEM;
+			goto exit;
+		}
+		spin_unlock(&mbox->lock);
+		dev_dbg(&(mbox->pdev->dev),
+			"Buffer full in blocking call! Sleeping...\n");
+		mbox->client_blocked = 1;
+		wait_for_completion(&mbox->buffer_available);
+		dev_dbg(&(mbox->pdev->dev),
+			"Blocking send was woken up! Trying again...\n");
+		spin_lock(&mbox->lock);
+	}
+
+	mbox->buffer[mbox->write_index] = mbox_msg;
+	mbox->write_index = (mbox->write_index + 1) % MBOX_BUF_SIZE;
+
+	/*
+	 * Indicate that we want an IRQ as soon as there is a slot
+	 * in the FIFO
+	 */
+	writel(MBOX_ENABLE_IRQ, mbox->virtbase_peer + MBOX_FIFO_THRES_FREE);
+
+exit:
+	spin_unlock(&mbox->lock);
+	return res;
+}
+EXPORT_SYMBOL(mbox_send);
+
+#if defined(CONFIG_DEBUG_FS)
+/*
+ * Expected input: <value> <nbr sends>
+ * Example: "echo 0xdeadbeef 4 > mbox-node" sends 0xdeadbeef 4 times
+ */
+static ssize_t mbox_write_fifo(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf,
+			       size_t count)
+{
+	unsigned long mbox_mess;
+	unsigned long nbr_sends;
+	unsigned long i;
+	char int_buf[16];
+	char *token;
+	char *val;
+
+	struct mbox *mbox = (struct mbox *) dev->platform_data;
+
+	strncpy((char *) &int_buf, buf, sizeof(int_buf));
+	token = (char *) &int_buf;
+
+	/* Parse message */
+	val = strsep(&token, " ");
+	if ((val == NULL) || (strict_strtoul(val, 16, &mbox_mess) != 0))
+		mbox_mess = 0xDEADBEEF;
+
+	val = strsep(&token, " ");
+	if ((val == NULL) || (strict_strtoul(val, 10, &nbr_sends) != 0))
+		nbr_sends = 1;
+
+	dev_dbg(dev, "Will write 0x%lX %ld times using data struct at 0x%X\n",
+		mbox_mess, nbr_sends, (u32) mbox);
+
+	for (i = 0; i < nbr_sends; i++)
+		mbox_send(mbox, mbox_mess, true);
+
+	return count;
+}
+
+static ssize_t mbox_read_fifo(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	int mbox_value;
+	struct mbox *mbox = (struct mbox *) dev->platform_data;
+
+	if ((readl(mbox->virtbase_local + MBOX_FIFO_STATUS) & 0x7) <= 0)
+		return sprintf(buf, "Mailbox is empty\n");
+
+	mbox_value = readl(mbox->virtbase_local + MBOX_FIFO_DATA);
+	writel(MBOX_LATCH, (mbox->virtbase_local + MBOX_FIFO_REMOVE));
+
+	return sprintf(buf, "0x%X\n", mbox_value);
+}
+
+static DEVICE_ATTR(fifo, S_IWUGO | S_IRUGO, mbox_read_fifo, mbox_write_fifo);
+
+static int mbox_show(struct seq_file *s, void *data)
+{
+	struct list_head *pos;
+	u8 mbox_index = 0;
+
+	list_for_each(pos, &mboxs) {
+		struct mbox *m =
+			(struct mbox *) list_entry(pos, struct mbox, list);
+		if (m == NULL) {
+			seq_printf(s,
+				   "Unable to retrieve mailbox %d\n",
+				   mbox_index);
+			continue;
+		}
+
+		spin_lock(&m->lock);
+		if ((m->virtbase_peer == NULL) || (m->virtbase_local == NULL)) {
+			seq_printf(s, "MAILBOX %d not setup or corrupt\n",
+				   mbox_index);
+			spin_unlock(&m->lock);
+			continue;
+		}
+
+		seq_printf(s,
+		"===========================\n"
+		" MAILBOX %d\n"
+		" PEER MAILBOX DUMP\n"
+		"---------------------------\n"
+		"FIFO:                 0x%X (%d)\n"
+		"Free     Threshold:   0x%.2X (%d)\n"
+		"Occupied Threshold:   0x%.2X (%d)\n"
+		"Status:               0x%.2X (%d)\n"
+		"   Free spaces  (ot):    %d (%d)\n"
+		"   Occup spaces (ot):    %d (%d)\n"
+		"===========================\n"
+		" LOCAL MAILBOX DUMP\n"
+		"---------------------------\n"
+		"FIFO:                 0x%.X (%d)\n"
+		"Free     Threshold:   0x%.2X (%d)\n"
+		"Occupied Threshold:   0x%.2X (%d)\n"
+		"Status:               0x%.2X (%d)\n"
+		"   Free spaces  (ot):    %d (%d)\n"
+		"   Occup spaces (ot):    %d (%d)\n"
+		"===========================\n"
+		"write_index: %d\n"
+		"read_index : %d\n"
+		"===========================\n"
+		"\n",
+		mbox_index,
+		readl(m->virtbase_peer + MBOX_FIFO_DATA),
+		readl(m->virtbase_peer + MBOX_FIFO_DATA),
+		readl(m->virtbase_peer + MBOX_FIFO_THRES_FREE),
+		readl(m->virtbase_peer + MBOX_FIFO_THRES_FREE),
+		readl(m->virtbase_peer + MBOX_FIFO_THRES_OCCUP),
+		readl(m->virtbase_peer + MBOX_FIFO_THRES_OCCUP),
+		readl(m->virtbase_peer + MBOX_FIFO_STATUS),
+		readl(m->virtbase_peer + MBOX_FIFO_STATUS),
+		(readl(m->virtbase_peer + MBOX_FIFO_STATUS) >> 4) & 0x7,
+		(readl(m->virtbase_peer + MBOX_FIFO_STATUS) >> 7) & 0x1,
+		(readl(m->virtbase_peer + MBOX_FIFO_STATUS) >> 0) & 0x7,
+		(readl(m->virtbase_peer + MBOX_FIFO_STATUS) >> 3) & 0x1,
+		readl(m->virtbase_local + MBOX_FIFO_DATA),
+		readl(m->virtbase_local + MBOX_FIFO_DATA),
+		readl(m->virtbase_local + MBOX_FIFO_THRES_FREE),
+		readl(m->virtbase_local + MBOX_FIFO_THRES_FREE),
+		readl(m->virtbase_local + MBOX_FIFO_THRES_OCCUP),
+		readl(m->virtbase_local + MBOX_FIFO_THRES_OCCUP),
+		readl(m->virtbase_local + MBOX_FIFO_STATUS),
+		readl(m->virtbase_local + MBOX_FIFO_STATUS),
+		(readl(m->virtbase_local + MBOX_FIFO_STATUS) >> 4) & 0x7,
+		(readl(m->virtbase_local + MBOX_FIFO_STATUS) >> 7) & 0x1,
+		(readl(m->virtbase_local + MBOX_FIFO_STATUS) >> 0) & 0x7,
+		(readl(m->virtbase_local + MBOX_FIFO_STATUS) >> 3) & 0x1,
+		m->write_index, m->read_index);
+		mbox_index++;
+		spin_unlock(&m->lock);
+	}
+
+	return 0;
+}
+
+static int mbox_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, mbox_show, NULL);
+}
+
+static const struct file_operations mbox_operations = {
+	.owner = THIS_MODULE,
+	.open = mbox_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+#endif
+
+static irqreturn_t mbox_irq(int irq, void *arg)
+{
+	u32 mbox_value;
+	int nbr_occup;
+	int nbr_free;
+	struct mbox *mbox = (struct mbox *) arg;
+
+	spin_lock(&mbox->lock);
+
+	dev_dbg(&(mbox->pdev->dev),
+		"mbox IRQ [%d] received. ri = %d, wi = %d\n",
+		irq, mbox->read_index, mbox->write_index);
+
+	/*
+	 * Check if we have any outgoing messages, and if there is space for
+	 * them in the FIFO.
+	 */
+	if (mbox->read_index != mbox->write_index) {
+		/*
+		 * Check by reading FREE for LOCAL since that indicates
+		 * OCCUP for PEER
+		 */
+		nbr_free = (readl(mbox->virtbase_local + MBOX_FIFO_STATUS)
+			    >> 4) & 0x7;
+		dev_dbg(&(mbox->pdev->dev),
+			"Status indicates %d empty spaces in the FIFO!\n",
+			nbr_free);
+
+		while ((nbr_free > 0) &&
+		       (mbox->read_index != mbox->write_index)) {
+			/* Write the message and latch it into the FIFO */
+			writel(mbox->buffer[mbox->read_index],
+			       (mbox->virtbase_peer + MBOX_FIFO_DATA));
+			writel(MBOX_LATCH,
+			       (mbox->virtbase_peer + MBOX_FIFO_ADD));
+			dev_dbg(&(mbox->pdev->dev),
+				"Wrote message 0x%X to addr 0x%X\n",
+				mbox->buffer[mbox->read_index],
+				(u32) (mbox->virtbase_peer + MBOX_FIFO_DATA));
+
+			nbr_free--;
+			mbox->read_index =
+				(mbox->read_index + 1) % MBOX_BUF_SIZE;
+		}
+
+		/*
+		 * Check if we still want IRQ:s when there is free
+		 * space to send
+		 */
+		if (mbox->read_index != mbox->write_index) {
+			dev_dbg(&(mbox->pdev->dev),
+				"Still have messages to send, but FIFO full. "
+				"Request IRQ again!\n");
+			writel(MBOX_ENABLE_IRQ,
+			       mbox->virtbase_peer + MBOX_FIFO_THRES_FREE);
+		} else {
+			dev_dbg(&(mbox->pdev->dev),
+				"No more messages to send. "
+				"Do not request IRQ again!\n");
+			writel(MBOX_DISABLE_IRQ,
+			       mbox->virtbase_peer + MBOX_FIFO_THRES_FREE);
+		}
+
+		/*
+		 * Check if we can signal any blocked clients that it is OK to
+		 * start buffering again
+		 */
+		if (mbox->client_blocked &&
+		    (((mbox->write_index + 1) % MBOX_BUF_SIZE)
+		     != mbox->read_index)) {
+			dev_dbg(&(mbox->pdev->dev),
+				"Waking up blocked client\n");
+			complete(&mbox->buffer_available);
+			mbox->client_blocked = 0;
+		}
+	}
+
+	/* Check if we have any incoming messages */
+	nbr_occup = readl(mbox->virtbase_local + MBOX_FIFO_STATUS) & 0x7;
+	if (nbr_occup == 0)
+		goto exit;
+
+	if (mbox->cb == NULL) {
+		dev_dbg(&(mbox->pdev->dev), "No receive callback registered, "
+			"leaving %d incoming messages in fifo!\n", nbr_occup);
+		goto exit;
+	}
+
+	/* Read and acknowledge the message */
+	mbox_value = readl(mbox->virtbase_local + MBOX_FIFO_DATA);
+	writel(MBOX_LATCH, (mbox->virtbase_local + MBOX_FIFO_REMOVE));
+
+	/* Notify consumer of new mailbox message */
+	dev_dbg(&(mbox->pdev->dev), "Calling callback for message 0x%X!\n",
+		mbox_value);
+	mbox->cb(mbox_value, mbox->client_data);
+
+exit:
+	dev_dbg(&(mbox->pdev->dev), "Exit mbox IRQ. ri = %d, wi = %d\n",
+		mbox->read_index, mbox->write_index);
+	spin_unlock(&mbox->lock);
+
+	return IRQ_HANDLED;
+}
+
+/* Setup is executed once for each mbox pair */
+struct mbox *mbox_setup(u8 mbox_id, mbox_recv_cb_t *mbox_cb, void *priv)
+{
+	struct resource *resource;
+	int irq;
+	int res;
+	struct mbox *mbox;
+
+	mbox = get_mbox_with_id(mbox_id);
+	if (mbox == NULL) {
+		dev_err(&(mbox->pdev->dev), "Incorrect mailbox id: %d!\n",
+			mbox_id);
+		goto exit;
+	}
+
+	/*
+	 * Check if mailbox has been allocated to someone else,
+	 * otherwise allocate it
+	 */
+	if (mbox->allocated) {
+		dev_err(&(mbox->pdev->dev), "Mailbox number %d is busy!\n",
+			mbox_id);
+		mbox = NULL;
+		goto exit;
+	}
+	mbox->allocated = true;
+
+	dev_dbg(&(mbox->pdev->dev), "Initiating mailbox number %d: 0x%X...\n",
+		mbox_id, (u32)mbox);
+
+	mbox->client_data = priv;
+	mbox->cb = mbox_cb;
+
+	/* Get addr for peer mailbox and ioremap it */
+	resource = platform_get_resource_byname(mbox->pdev,
+						IORESOURCE_MEM,
+						"mbox_peer");
+	if (resource == NULL) {
+		dev_err(&(mbox->pdev->dev),
+			"Unable to retrieve mbox peer resource\n");
+		mbox = NULL;
+		goto exit;
+	}
+	dev_dbg(&(mbox->pdev->dev),
+		"Resource name: %s start: 0x%X, end: 0x%X\n",
+		resource->name, resource->start, resource->end);
+	mbox->virtbase_peer =
+		ioremap(resource->start, resource->end - resource->start);
+	if (!mbox->virtbase_peer) {
+		dev_err(&(mbox->pdev->dev), "Unable to ioremap peer mbox\n");
+		mbox = NULL;
+		goto exit;
+	}
+	dev_dbg(&(mbox->pdev->dev),
+		"ioremapped peer physical: (0x%X-0x%X) to virtual: 0x%X\n",
+		resource->start, resource->end, (u32) mbox->virtbase_peer);
+
+	/* Get addr for local mailbox and ioremap it */
+	resource = platform_get_resource_byname(mbox->pdev,
+						IORESOURCE_MEM,
+						"mbox_local");
+	if (resource == NULL) {
+		dev_err(&(mbox->pdev->dev),
+			"Unable to retrieve mbox local resource\n");
+		mbox = NULL;
+		goto exit;
+	}
+	dev_dbg(&(mbox->pdev->dev),
+		"Resource name: %s start: 0x%X, end: 0x%X\n",
+		resource->name, resource->start, resource->end);
+	mbox->virtbase_local =
+		ioremap(resource->start, resource->end - resource->start);
+	if (!mbox->virtbase_local) {
+		dev_err(&(mbox->pdev->dev), "Unable to ioremap local mbox\n");
+		mbox = NULL;
+		goto exit;
+	}
+	dev_dbg(&(mbox->pdev->dev),
+		"ioremapped local physical: (0x%X-0x%X) to virtual: 0x%X\n",
+		resource->start, resource->end, (u32) mbox->virtbase_peer);
+
+	init_completion(&mbox->buffer_available);
+	mbox->client_blocked = 0;
+
+	/* Get IRQ for mailbox and allocate it */
+	irq = platform_get_irq_byname(mbox->pdev, "mbox_irq");
+	if (irq < 0) {
+		dev_err(&(mbox->pdev->dev),
+			"Unable to retrieve mbox irq resource\n");
+		mbox = NULL;
+		goto exit;
+	}
+
+	dev_dbg(&(mbox->pdev->dev), "Allocating irq %d...\n", irq);
+	res = request_irq(irq, mbox_irq, 0, mbox->name, (void *) mbox);
+	if (res < 0) {
+		dev_err(&(mbox->pdev->dev),
+			"Unable to allocate mbox irq %d\n", irq);
+		mbox = NULL;
+		goto exit;
+	}
+
+	/* Set up mailbox to not launch IRQ on free space in mailbox */
+	writel(MBOX_DISABLE_IRQ, mbox->virtbase_peer + MBOX_FIFO_THRES_FREE);
+
+	/*
+	 * Set up mailbox to launch IRQ on new message if we have
+	 * a callback set. If not, do not raise IRQ, but keep message
+	 * in FIFO for manual retrieval
+	 */
+	if (mbox_cb != NULL)
+		writel(MBOX_ENABLE_IRQ,
+		       mbox->virtbase_local + MBOX_FIFO_THRES_OCCUP);
+	else
+		writel(MBOX_DISABLE_IRQ,
+		       mbox->virtbase_local + MBOX_FIFO_THRES_OCCUP);
+
+#if defined(CONFIG_DEBUG_FS)
+	res = device_create_file(&(mbox->pdev->dev), &dev_attr_fifo);
+	if (res != 0)
+		dev_warn(&(mbox->pdev->dev),
+			 "Unable to create mbox sysfs entry");
+
+	(void) debugfs_create_file("mbox", S_IFREG | S_IRUGO, NULL,
+				   NULL, &mbox_operations);
+#endif
+
+	dev_info(&(mbox->pdev->dev),
+		 "Mailbox driver with index %d initated!\n", mbox_id);
+
+exit:
+	return mbox;
+}
+EXPORT_SYMBOL(mbox_setup);
+
+
+int __init mbox_probe(struct platform_device *pdev)
+{
+	struct mbox local_mbox;
+	struct mbox *mbox;
+	int res = 0;
+	dev_dbg(&(pdev->dev), "Probing mailbox (pdev = 0x%X)...\n", (u32) pdev);
+
+	memset(&local_mbox, 0x0, sizeof(struct mbox));
+
+	/* Associate our mbox data with the platform device */
+	res = platform_device_add_data(pdev,
+				       (void *) &local_mbox,
+				       sizeof(struct mbox));
+	if (res != 0) {
+		dev_err(&(pdev->dev),
+			"Unable to allocate driver platform data!\n");
+		goto exit;
+	}
+
+	mbox = (struct mbox *) pdev->dev.platform_data;
+	mbox->pdev = pdev;
+	mbox->write_index = 0;
+	mbox->read_index = 0;
+
+	INIT_LIST_HEAD(&(mbox->list));
+	list_add_tail(&(mbox->list), &mboxs);
+
+	sprintf(mbox->name, "%s", MBOX_NAME);
+	spin_lock_init(&mbox->lock);
+
+	dev_info(&(pdev->dev), "Mailbox driver loaded\n");
+
+exit:
+	return res;
+}
+
+static struct platform_driver mbox_driver = {
+	.driver = {
+		.name = MBOX_NAME,
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init mbox_init(void)
+{
+	return platform_driver_probe(&mbox_driver, mbox_probe);
+}
+
+module_init(mbox_init);
+
+void __exit mbox_exit(void)
+{
+	platform_driver_unregister(&mbox_driver);
+}
+
+module_exit(mbox_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("MBOX driver");