HSI: hsi_char: Add HSI char device driver

Add HSI char device driver to the kernel.

Signed-off-by: Andras Domokos <andras.domokos@nokia.com>
Signed-off-by: Carlos Chinea <carlos.chinea@nokia.com>

2 files changed, 865 insertions, 0 deletions

diff --git a/drivers/hsi/clients/hsi_char.c b/drivers/hsi/clients/hsi_char.c
new file mode 100644
index 000000000000..88a050df2389
--- /dev/null
+++ b/drivers/hsi/clients/hsi_char.c
@@ -0,0 +1,802 @@
+/*
+ * HSI character device driver, implements the character device
+ * interface.
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ *
+ * Contact: Andras Domokos <andras.domokos@nokia.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * 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 St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/atomic.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/kmemleak.h>
+#include <linux/ioctl.h>
+#include <linux/wait.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/device.h>
+#include <linux/cdev.h>
+#include <linux/uaccess.h>
+#include <linux/scatterlist.h>
+#include <linux/stat.h>
+#include <linux/hsi/hsi.h>
+#include <linux/hsi/hsi_char.h>
+
+#define HSC_DEVS                16 /* Num of channels */
+#define HSC_MSGS                4
+
+#define HSC_RXBREAK             0
+
+#define HSC_ID_BITS             6
+#define HSC_PORT_ID_BITS        4
+#define HSC_ID_MASK             3
+#define HSC_PORT_ID_MASK        3
+#define HSC_CH_MASK             0xf
+
+/*
+ * We support up to 4 controllers that can have up to 4
+ * ports, which should currently be more than enough.
+ */
+#define HSC_BASEMINOR(id, port_id) \
+                ((((id) & HSC_ID_MASK) << HSC_ID_BITS) | \
+                (((port_id) & HSC_PORT_ID_MASK) << HSC_PORT_ID_BITS))
+
+enum {
+        HSC_CH_OPEN,
+        HSC_CH_READ,
+        HSC_CH_WRITE,
+        HSC_CH_WLINE,
+};
+
+enum {
+        HSC_RX,
+        HSC_TX,
+};
+
+struct hsc_client_data;
+/**
+ * struct hsc_channel - hsi_char internal channel data
+ * @ch: channel number
+ * @flags: Keeps state of the channel (open/close, reading, writing)
+ * @free_msgs_list: List of free HSI messages/requests
+ * @rx_msgs_queue: List of pending RX requests
+ * @tx_msgs_queue: List of pending TX requests
+ * @lock: Serialize access to the lists
+ * @cl: reference to the associated hsi_client
+ * @cl_data: reference to the client data that this channels belongs to
+ * @rx_wait: RX requests wait queue
+ * @tx_wait: TX requests wait queue
+ */
+struct hsc_channel {
+        unsigned int            ch;
+        unsigned long           flags;
+        struct list_head        free_msgs_list;
+        struct list_head        rx_msgs_queue;
+        struct list_head        tx_msgs_queue;
+        spinlock_t              lock;
+        struct hsi_client       *cl;
+        struct hsc_client_data *cl_data;
+        wait_queue_head_t       rx_wait;
+        wait_queue_head_t       tx_wait;
+};
+
+/**
+ * struct hsc_client_data - hsi_char internal client data
+ * @cdev: Characther device associated to the hsi_client
+ * @lock: Lock to serialize open/close access
+ * @flags: Keeps track of port state (rx hwbreak armed)
+ * @usecnt: Use count for claiming the HSI port (mutex protected)
+ * @cl: Referece to the HSI client
+ * @channels: Array of channels accessible by the client
+ */
+struct hsc_client_data {
+        struct cdev             cdev;
+        struct mutex            lock;
+        unsigned long           flags;
+        unsigned int            usecnt;
+        struct hsi_client       *cl;
+        struct hsc_channel      channels[HSC_DEVS];
+};
+
+/* Stores the major number dynamically allocated for hsi_char */
+static unsigned int hsc_major;
+/* Maximum buffer size that hsi_char will accept from userspace */
+static unsigned int max_data_size = 0x1000;
+module_param(max_data_size, uint, S_IRUSR | S_IWUSR);
+MODULE_PARM_DESC(max_data_size, "max read/write data size [4,8..65536] (^2)");
+
+static void hsc_add_tail(struct hsc_channel *channel, struct hsi_msg *msg,
+                                                        struct list_head *queue)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&channel->lock, flags);
+        list_add_tail(&msg->link, queue);
+        spin_unlock_irqrestore(&channel->lock, flags);
+}
+
+static struct hsi_msg *hsc_get_first_msg(struct hsc_channel *channel,
+                                                        struct list_head *queue)
+{
+        struct hsi_msg *msg = NULL;
+        unsigned long flags;
+
+        spin_lock_irqsave(&channel->lock, flags);
+
+        if (list_empty(queue))
+                goto out;
+
+        msg = list_first_entry(queue, struct hsi_msg, link);
+        list_del(&msg->link);
+out:
+        spin_unlock_irqrestore(&channel->lock, flags);
+
+        return msg;
+}
+
+static inline void hsc_msg_free(struct hsi_msg *msg)
+{
+        kfree(sg_virt(msg->sgt.sgl));
+        hsi_free_msg(msg);
+}
+
+static void hsc_free_list(struct list_head *list)
+{
+        struct hsi_msg *msg, *tmp;
+
+        list_for_each_entry_safe(msg, tmp, list, link) {
+                list_del(&msg->link);
+                hsc_msg_free(msg);
+        }
+}
+
+static void hsc_reset_list(struct hsc_channel *channel, struct list_head *l)
+{
+        unsigned long flags;
+        LIST_HEAD(list);
+
+        spin_lock_irqsave(&channel->lock, flags);
+        list_splice_init(l, &list);
+        spin_unlock_irqrestore(&channel->lock, flags);
+
+        hsc_free_list(&list);
+}
+
+static inline struct hsi_msg *hsc_msg_alloc(unsigned int alloc_size)
+{
+        struct hsi_msg *msg;
+        void *buf;
+
+        msg = hsi_alloc_msg(1, GFP_KERNEL);
+        if (!msg)
+                goto out;
+        buf = kmalloc(alloc_size, GFP_KERNEL);
+        if (!buf) {
+                hsi_free_msg(msg);