drivers/char: add MSM smd_pkt driver

Add smd_pkt driver which provides device interface to smd packet ports.
Signed-off-by: NNiranjana Vishwanathapura <nvishwan@codeaurora.org>
Cc: Brian Swetland <swetland@google.com>
Cc: Greg KH <gregkh@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: David Brown <davidb@codeaurora.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/char/Kconfig

@@ -608,5 +608,13 @@ config RAMOOPS
 	  This enables panic and oops messages to be logged to a circular
 	  buffer in RAM where it can be read back at some later point.
 
+config MSM_SMD_PKT
+	bool "Enable device interface for some SMD packet ports"
+	default n
+	depends on MSM_SMD
+	help
+	  Enables userspace clients to read and write to some packet SMD
+	  ports via device interface for MSM chipset.
+
 endmenu
 

drivers/char/Makefile

@@ -9,6 +9,7 @@ obj-$(CONFIG_ATARI_DSP56K)	+= dsp56k.o
 obj-$(CONFIG_VIRTIO_CONSOLE)	+= virtio_console.o
 obj-$(CONFIG_RAW_DRIVER)	+= raw.o
 obj-$(CONFIG_SGI_SNSC)		+= snsc.o snsc_event.o
+obj-$(CONFIG_MSM_SMD_PKT)	+= msm_smd_pkt.o
 obj-$(CONFIG_MSPEC)		+= mspec.o
 obj-$(CONFIG_MMTIMER)		+= mmtimer.o
 obj-$(CONFIG_UV_MMTIMER)	+= uv_mmtimer.o

drivers/char/msm_smd_pkt.c

+/* Copyright (c) 2008-2010, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ */
+/*
+ * SMD Packet Driver -- Provides userspace interface to SMD packet ports.
+ */
+
+#include <linux/slab.h>
+#include <linux/cdev.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/sched.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/uaccess.h>
+#include <linux/workqueue.h>
+#include <linux/poll.h>
+
+#include <mach/msm_smd.h>
+
+#define NUM_SMD_PKT_PORTS 9
+#define DEVICE_NAME "smdpkt"
+#define MAX_BUF_SIZE 2048
+
+struct smd_pkt_dev {
+	struct cdev cdev;
+	struct device *devicep;
+
+	struct smd_channel *ch;
+	int open_count;
+	struct mutex ch_lock;
+	struct mutex rx_lock;
+	struct mutex tx_lock;
+	wait_queue_head_t ch_read_wait_queue;
+	wait_queue_head_t ch_opened_wait_queue;
+
+	int i;
+
+	unsigned char tx_buf[MAX_BUF_SIZE];
+	unsigned char rx_buf[MAX_BUF_SIZE];
+	int remote_open;
+
+} *smd_pkt_devp[NUM_SMD_PKT_PORTS];
+
+struct class *smd_pkt_classp;
+static dev_t smd_pkt_number;
+
+static int msm_smd_pkt_debug_enable;
+module_param_named(debug_enable, msm_smd_pkt_debug_enable,
+		   int, S_IRUGO | S_IWUSR | S_IWGRP);
+
+#ifdef DEBUG
+#define D_DUMP_BUFFER(prestr, cnt, buf) do {			\
+		int i;						\
+		if (msm_smd_pkt_debug_enable) {			\
+			pr_debug("%s", prestr);			\
+			for (i = 0; i < cnt; i++)		\
+				pr_debug("%.2x", buf[i]);	\
+			pr_debug("\n");				\
+		}						\
+	} while (0)
+#else
+#define D_DUMP_BUFFER(prestr, cnt, buf) do {} while (0)
+#endif
+
+#ifdef DEBUG
+#define DBG(x...) do {			\
+	if (msm_smd_pkt_debug_enable)	\
+		pr_debug(x);		\
+	} while (0)
+#else
+#define DBG(x...) do {} while (0)
+#endif
+
+static void check_and_wakeup_reader(struct smd_pkt_dev *smd_pkt_devp)
+{
+	int sz;
+
+	if (!smd_pkt_devp || !smd_pkt_devp->ch)
+		return;
+
+	sz = smd_cur_packet_size(smd_pkt_devp->ch);
+	if (sz == 0) {
+		DBG("no packet\n");
+		return;
+	}
+	if (sz > smd_read_avail(smd_pkt_devp->ch)) {
+		DBG("incomplete packet\n");
+		return;
+	}
+
+	DBG("waking up reader\n");
+	wake_up_interruptible(&smd_pkt_devp->ch_read_wait_queue);
+}
+
+static int smd_pkt_read(struct file *file, char __user *buf,
+			size_t count, loff_t *ppos)
+{
+	int r, bytes_read;
+	struct smd_pkt_dev *smd_pkt_devp;
+	struct smd_channel *chl;
+
+	DBG("read %d bytes\n", count);
+	if (count > MAX_BUF_SIZE)
+		return -EINVAL;
+
+	smd_pkt_devp = file->private_data;
+	if (!smd_pkt_devp || !smd_pkt_devp->ch)
+		return -EINVAL;
+
+	chl = smd_pkt_devp->ch;
+wait_for_packet:
+	r = wait_event_interruptible(smd_pkt_devp->ch_read_wait_queue,
+				     (smd_cur_packet_size(chl) > 0 &&
+				      smd_read_avail(chl) >=
+				      smd_cur_packet_size(chl)));
+
+	if (r < 0) {
+		if (r != -ERESTARTSYS)
+			pr_err("wait returned %d\n", r);
+		return r;
+	}
+
+	mutex_lock(&smd_pkt_devp->rx_lock);
+
+	bytes_read = smd_cur_packet_size(smd_pkt_devp->ch);
+	if (bytes_read == 0 ||
+	    bytes_read < smd_read_avail(smd_pkt_devp->ch)) {
+		mutex_unlock(&smd_pkt_devp->rx_lock);
+		DBG("Nothing to read\n");
+		goto wait_for_packet;
+	}
+
+	if (bytes_read > count) {
+		mutex_unlock(&smd_pkt_devp->rx_lock);
+		pr_info("packet size %d > buffer size %d", bytes_read, count);
+		return -EINVAL;
+	}
+
+	r = smd_read(smd_pkt_devp->ch, smd_pkt_devp->rx_buf, bytes_read);
+	if (r != bytes_read) {
+		mutex_unlock(&smd_pkt_devp->rx_lock);
+		pr_err("smd_read failed to read %d bytes: %d\n", bytes_read, r);
+		return -EIO;
+	}
+
+	D_DUMP_BUFFER("read: ", bytes_read, smd_pkt_devp->rx_buf);
+	r = copy_to_user(buf, smd_pkt_devp->rx_buf, bytes_read);
+	mutex_unlock(&smd_pkt_devp->rx_lock);
+	if (r) {
+		pr_err("copy_to_user failed %d\n", r);
+		return -EFAULT;
+	}
+
+	DBG("read complete %d bytes\n", bytes_read);
+	check_and_wakeup_reader(smd_pkt_devp);
+
+	return bytes_read;
+}
+
+static int smd_pkt_write(struct file *file, const char __user *buf,
+			 size_t count, loff_t *ppos)
+{
+	int r;
+	struct smd_pkt_dev *smd_pkt_devp;
+
+	if (count > MAX_BUF_SIZE)
+		return -EINVAL;
+
+	DBG("writting %d bytes\n", count);
+
+	smd_pkt_devp = file->private_data;
+	if (!smd_pkt_devp || !smd_pkt_devp->ch)
+		return -EINVAL;
+
+	mutex_lock(&smd_pkt_devp->tx_lock);
+	if (smd_write_avail(smd_pkt_devp->ch) < count) {
+		mutex_unlock(&smd_pkt_devp->tx_lock);
+		DBG("Not enough space to write\n");
+		return -ENOMEM;
+	}
+
+	D_DUMP_BUFFER("write: ", count, buf);
+	r = copy_from_user(smd_pkt_devp->tx_buf, buf, count);
+	if (r) {
+		mutex_unlock(&smd_pkt_devp->tx_lock);
+		pr_err("copy_from_user failed %d\n", r);
+		return -EFAULT;
+	}
+
+	r = smd_write(smd_pkt_devp->ch, smd_pkt_devp->tx_buf, count);
+	if (r != count) {
+		mutex_unlock(&smd_pkt_devp->tx_lock);
+		pr_err("smd_write failed to write %d bytes: %d.\n", count, r);
+		return -EIO;
+	}
+	mutex_unlock(&smd_pkt_devp->tx_lock);
+
+	DBG("wrote %d bytes\n", count);
+	return count;
+}
+
+static unsigned int smd_pkt_poll(struct file *file, poll_table *wait)
+{
+	struct smd_pkt_dev *smd_pkt_devp;
+	unsigned int mask = 0;
+
+	smd_pkt_devp = file->private_data;
+	if (!smd_pkt_devp)
+		return POLLERR;
+
+	DBG("poll waiting\n");
+	poll_wait(file, &smd_pkt_devp->ch_read_wait_queue, wait);
+	if (smd_read_avail(smd_pkt_devp->ch))
+		mask |= POLLIN | POLLRDNORM;
+
+	DBG("poll return\n");
+	return mask;
+}
+
+static void smd_pkt_ch_notify(void *priv, unsigned event)
+{
+	struct smd_pkt_dev *smd_pkt_devp = priv;
+
+	if (smd_pkt_devp->ch == 0)
+		return;
+
+	switch (event) {
+	case SMD_EVENT_DATA:
+		DBG("data\n");
+		check_and_wakeup_reader(smd_pkt_devp);
+		break;
+
+	case SMD_EVENT_OPEN:
+		DBG("remote open\n");
+		smd_pkt_devp->remote_open = 1;
+		wake_up_interruptible(&smd_pkt_devp->ch_opened_wait_queue);
+		break;
+
+	case SMD_EVENT_CLOSE:
+		smd_pkt_devp->remote_open = 0;
+		pr_info("remote closed\n");
+		break;
+
+	default:
+		pr_err("unknown event %d\n", event);
+		break;
+	}
+}
+
+static char *smd_pkt_dev_name[] = {
+	"smdcntl0",
+	"smdcntl1",
+	"smdcntl2",
+	"smdcntl3",
+	"smdcntl4",
+	"smdcntl5",
+	"smdcntl6",
+	"smdcntl7",
+	"smd22",
+};
+
+static char *smd_ch_name[] = {
+	"DATA5_CNTL",
+	"DATA6_CNTL",
+	"DATA7_CNTL",
+	"DATA8_CNTL",
+	"DATA9_CNTL",
+	"DATA12_CNTL",
+	"DATA13_CNTL",
+	"DATA14_CNTL",
+	"DATA22",
+};
+
+static int smd_pkt_open(struct inode *inode, struct file *file)
+{
+	int r = 0;
+	struct smd_pkt_dev *smd_pkt_devp;
+
+	smd_pkt_devp = container_of(inode->i_cdev, struct smd_pkt_dev, cdev);
+	if (!smd_pkt_devp)
+		return -EINVAL;
+
+	file->private_data = smd_pkt_devp;
+
+	mutex_lock(&smd_pkt_devp->ch_lock);
+	if (smd_pkt_devp->open_count == 0) {
+		r = smd_open(smd_ch_name[smd_pkt_devp->i],
+			     &smd_pkt_devp->ch, smd_pkt_devp,
+			     smd_pkt_ch_notify);
+		if (r < 0) {
+			pr_err("smd_open failed for %s, %d\n",
+			       smd_ch_name[smd_pkt_devp->i], r);
+			goto out;
+		}
+
+		r = wait_event_interruptible_timeout(
+				smd_pkt_devp->ch_opened_wait_queue,
+				smd_pkt_devp->remote_open,
+				msecs_to_jiffies(2 * HZ));
+		if (r == 0)
+			r = -ETIMEDOUT;
+
+		if (r < 0) {
+			pr_err("wait returned %d\n", r);
+			smd_close(smd_pkt_devp->ch);
+			smd_pkt_devp->ch = 0;
+		} else {
+			smd_pkt_devp->open_count++;
+			r = 0;
+		}
+	}
+out:
+	mutex_unlock(&smd_pkt_devp->ch_lock);
+	return r;
+}
+
+static int smd_pkt_release(struct inode *inode, struct file *file)
+{
+	int r = 0;
+	struct smd_pkt_dev *smd_pkt_devp = file->private_data;
+
+	if (!smd_pkt_devp)
+		return -EINVAL;
+
+	mutex_lock(&smd_pkt_devp->ch_lock);
+	if (--smd_pkt_devp->open_count == 0) {
+		r = smd_close(smd_pkt_devp->ch);
+		smd_pkt_devp->ch = 0;
+	}
+	mutex_unlock(&smd_pkt_devp->ch_lock);
+
+	return r;
+}
+
+static const struct file_operations smd_pkt_fops = {
+	.owner = THIS_MODULE,
+	.open = smd_pkt_open,
+	.release = smd_pkt_release,
+	.read = smd_pkt_read,
+	.write = smd_pkt_write,
+	.poll = smd_pkt_poll,
+};
+
+static int __init smd_pkt_init(void)
+{
+	int i;
+	int r;
+
+	r = alloc_chrdev_region(&smd_pkt_number, 0,
+				NUM_SMD_PKT_PORTS, DEVICE_NAME);
+	if (r) {
+		pr_err("alloc_chrdev_region() failed %d\n", r);
+		return r;
+	}
+
+	smd_pkt_classp = class_create(THIS_MODULE, DEVICE_NAME);
+	if (IS_ERR(smd_pkt_classp)) {
+		r = PTR_ERR(smd_pkt_classp);
+		pr_err("class_create() failed %d\n", r);
+		goto unreg_chardev;
+	}
+
+	for (i = 0; i < NUM_SMD_PKT_PORTS; ++i) {
+		smd_pkt_devp[i] = kzalloc(sizeof(struct smd_pkt_dev),
+					  GFP_KERNEL);
+		if (IS_ERR(smd_pkt_devp[i])) {
+			r = PTR_ERR(smd_pkt_devp[i]);
+			pr_err("kmalloc() failed %d\n", r);
+			goto clean_cdevs;
+		}
+
+		smd_pkt_devp[i]->i = i;
+
+		init_waitqueue_head(&smd_pkt_devp[i]->ch_read_wait_queue);
+		smd_pkt_devp[i]->remote_open = 0;
+		init_waitqueue_head(&smd_pkt_devp[i]->ch_opened_wait_queue);
+
+		mutex_init(&smd_pkt_devp[i]->ch_lock);
+		mutex_init(&smd_pkt_devp[i]->rx_lock);
+		mutex_init(&smd_pkt_devp[i]->tx_lock);
+
+		cdev_init(&smd_pkt_devp[i]->cdev, &smd_pkt_fops);
+		smd_pkt_devp[i]->cdev.owner = THIS_MODULE;
+
+		r = cdev_add(&smd_pkt_devp[i]->cdev,
+			     (smd_pkt_number + i), 1);
+		if (r) {
+			pr_err("cdev_add() failed %d\n", r);
+			kfree(smd_pkt_devp[i]);
+			goto clean_cdevs;
+		}
+
+		smd_pkt_devp[i]->devicep =
+			device_create(smd_pkt_classp, NULL,
+				      (smd_pkt_number + i), NULL,
+				      smd_pkt_dev_name[i]);
+		if (IS_ERR(smd_pkt_devp[i]->devicep)) {
+			r = PTR_ERR(smd_pkt_devp[i]->devicep);
+			pr_err("device_create() failed %d\n", r);
+			cdev_del(&smd_pkt_devp[i]->cdev);
+			kfree(smd_pkt_devp[i]);
+			goto clean_cdevs;
+		}
+
+	}
+
+	pr_info("SMD Packet Port Driver Initialized.\n");
+	return 0;
+
+clean_cdevs:
+	if (i > 0) {
+		while (--i >= 0) {
+			mutex_destroy(&smd_pkt_devp[i]->ch_lock);
+			mutex_destroy(&smd_pkt_devp[i]->rx_lock);
+			mutex_destroy(&smd_pkt_devp[i]->tx_lock);
+			cdev_del(&smd_pkt_devp[i]->cdev);
+			kfree(smd_pkt_devp[i]);
+			device_destroy(smd_pkt_classp,
+				       MKDEV(MAJOR(smd_pkt_number), i));
+		}
+	}
+
+	class_destroy(smd_pkt_classp);
+unreg_chardev:
+	unregister_chrdev_region(MAJOR(smd_pkt_number), NUM_SMD_PKT_PORTS);
+	return r;
+}
+module_init(smd_pkt_init);
+
+static void __exit smd_pkt_cleanup(void)
+{
+	int i;
+
+	for (i = 0; i < NUM_SMD_PKT_PORTS; ++i) {
+		mutex_destroy(&smd_pkt_devp[i]->ch_lock);
+		mutex_destroy(&smd_pkt_devp[i]->rx_lock);
+		mutex_destroy(&smd_pkt_devp[i]->tx_lock);
+		cdev_del(&smd_pkt_devp[i]->cdev);
+		kfree(smd_pkt_devp[i]);
+		device_destroy(smd_pkt_classp,
+			       MKDEV(MAJOR(smd_pkt_number), i));
+	}
+
+	class_destroy(smd_pkt_classp);
+	unregister_chrdev_region(MAJOR(smd_pkt_number), NUM_SMD_PKT_PORTS);
+}
+module_exit(smd_pkt_cleanup);
+
+MODULE_DESCRIPTION("MSM Shared Memory Packet Port");
+MODULE_LICENSE("GPL v2");