drivers/char: add MSM smd_pkt driver

Add smd_pkt driver which provides device interface to smd packet ports.

Signed-off-by: Niranjana 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 475 insertions, 0 deletions

diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 04f8b2d083c6..ad59b4e0a9b5 100644
--- a/drivers/char/Kconfig
+++ b/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
 
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 057f65452e7b..7a00672bd85d 100644
--- a/drivers/char/Makefile
+++ b/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
diff --git a/drivers/char/msm_smd_pkt.c b/drivers/char/msm_smd_pkt.c
new file mode 100644
index 000000000000..b6f8a65c9960
--- /dev/null
+++ b/drivers/char/msm_smd_pkt.c
@@ -0,0 +1,466 @@
+/* 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");