1 files changed, 507 insertions, 0 deletions

diff --git a/drivers/hsi/hsi.c b/drivers/hsi/hsi.c
new file mode 100644
index 000000000000..2d58f939d27f
--- /dev/null
+++ b/drivers/hsi/hsi.c
@@ -0,0 +1,507 @@
+/*
+ * HSI core.
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ *
+ * Contact: Carlos Chinea <carlos.chinea@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/hsi/hsi.h>
+#include <linux/compiler.h>
+#include <linux/list.h>
+#include <linux/kobject.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/notifier.h>
+#include "hsi_core.h"
+
+static ssize_t modalias_show(struct device *dev,
+                        struct device_attribute *a __maybe_unused, char *buf)
+{
+        return sprintf(buf, "hsi:%s\n", dev_name(dev));
+}
+
+static struct device_attribute hsi_bus_dev_attrs[] = {
+        __ATTR_RO(modalias),
+        __ATTR_NULL,
+};
+
+static int hsi_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+        add_uevent_var(env, "MODALIAS=hsi:%s", dev_name(dev));
+
+        return 0;
+}
+
+static int hsi_bus_match(struct device *dev, struct device_driver *driver)
+{
+        return strcmp(dev_name(dev), driver->name) == 0;
+}
+
+static struct bus_type hsi_bus_type = {
+        .name           = "hsi",
+        .dev_attrs      = hsi_bus_dev_attrs,
+        .match          = hsi_bus_match,
+        .uevent         = hsi_bus_uevent,
+};
+
+static void hsi_client_release(struct device *dev)
+{
+        kfree(to_hsi_client(dev));
+}
+
+static void hsi_new_client(struct hsi_port *port, struct hsi_board_info *info)
+{
+        struct hsi_client *cl;
+
+        cl = kzalloc(sizeof(*cl), GFP_KERNEL);
+        if (!cl)
+                return;
+        cl->tx_cfg = info->tx_cfg;
+        cl->rx_cfg = info->rx_cfg;
+        cl->device.bus = &hsi_bus_type;
+        cl->device.parent = &port->device;
+        cl->device.release = hsi_client_release;
+        dev_set_name(&cl->device, info->name);
+        cl->device.platform_data = info->platform_data;
+        if (info->archdata)
+                cl->device.archdata = *info->archdata;
+        if (device_register(&cl->device) < 0) {
+                pr_err("hsi: failed to register client: %s\n", info->name);
+                put_device(&cl->device);
+        }
+}
+
+static void hsi_scan_board_info(struct hsi_controller *hsi)
+{
+        struct hsi_cl_info *cl_info;
+        struct hsi_port *p;
+
+        list_for_each_entry(cl_info, &hsi_board_list, list)
+                if (cl_info->info.hsi_id == hsi->id) {
+                        p = hsi_find_port_num(hsi, cl_info->info.port);
+                        if (!p)
+                                continue;
+                        hsi_new_client(p, &cl_info->info);
+                }
+}
+
+static int hsi_remove_client(struct device *dev, void *data __maybe_unused)
+{
+        device_unregister(dev);
+
+        return 0;
+}
+
+static int hsi_remove_port(struct device *dev, void *data __maybe_unused)
+{
+        device_for_each_child(dev, NULL, hsi_remove_client);
+        device_unregister(dev);
+
+        return 0;
+}
+
+static void hsi_controller_release(struct device *dev)
+{
+        struct hsi_controller *hsi = to_hsi_controller(dev);
+
+        kfree(hsi->port);
+        kfree(hsi);
+}
+
+static void hsi_port_release(struct device *dev)
+{
+        kfree(to_hsi_port(dev));
+}
+
+/**
+ * hsi_unregister_controller - Unregister an HSI controller
+ * @hsi: The HSI controller to register
+ */
+void hsi_unregister_controller(struct hsi_controller *hsi)
+{
+        device_for_each_child(&hsi->device, NULL, hsi_remove_port);
+        device_unregister(&hsi->device);
+}
+EXPORT_SYMBOL_GPL(hsi_unregister_controller);
+
+/**
+ * hsi_register_controller - Register an HSI controller and its ports
+ * @hsi: The HSI controller to register
+ *
+ * Returns -errno on failure, 0 on success.
+ */
+int hsi_register_controller(struct hsi_controller *hsi)
+{
+        unsigned int i;
+        int err;
+
+        err = device_add(&hsi->device);
+        if (err < 0)
+                return err;
+        for (i = 0; i < hsi->num_ports; i++) {
+                hsi->port[i]->device.parent = &hsi->device;
+                err = device_add(&hsi->port[i]->device);
+                if (err < 0)
+                        goto out;
+        }
+        /* Populate HSI bus with HSI clients */
+        hsi_scan_board_info(hsi);
+
+        return 0;
+out:
+        while (i-- > 0)
+                device_del(&hsi->port[i]->device);
+        device_del(&hsi->device);
+
+        return err;
+}
+EXPORT_SYMBOL_GPL(hsi_register_controller);
+
+/**
+ * hsi_register_client_driver - Register an HSI client to the HSI bus
+ * @drv: HSI client driver to register
+ *
+ * Returns -errno on failure, 0 on success.
+ */
+int hsi_register_client_driver(struct hsi_client_driver *drv)
+{
+        drv->driver.bus = &hsi_bus_type;
+
+        return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(hsi_register_client_driver);
+
+static inline int hsi_dummy_msg(struct hsi_msg *msg __maybe_unused)
+{
+        return 0;
+}
+
+static inline int hsi_dummy_cl(struct hsi_client *cl __maybe_unused)
+{
+        return 0;
+}
+
+/**
+ * hsi_put_controller - Free an HSI controller
+ *
+ * @hsi: Pointer to the HSI controller to freed
+ *
+ * HSI controller drivers should only use this function if they need
+ * to free their allocated hsi_controller structures before a successful
+ * call to hsi_register_controller. Other use is not allowed.
+ */
+void hsi_put_controller(struct hsi_controller *hsi)
+{
+        unsigned int i;
+
+        if (!hsi)
+                return;
+
+        for (i = 0; i < hsi->num_ports; i++)
+                if (hsi->port && hsi->port[i])
+                        put_device(&hsi->port[i]->device);
+        put_device(&hsi->device);
+}
+EXPORT_SYMBOL_GPL(hsi_put_controller);
+
+/**
+ * hsi_alloc_controller - Allocate an HSI controller and its ports
+ * @n_ports: Number of ports on the HSI controller
+ * @flags: Kernel allocation flags
+ *
+ * Return NULL on failure or a pointer to an hsi_controller on success.
+ */
+struct hsi_controller *hsi_alloc_controller(unsigned int n_ports, gfp_t flags)
+{
+        struct hsi_controller   *hsi;
+        struct hsi_port         **port;
+        unsigned int            i;
+
+        if (!n_ports)
+                return NULL;
+
+        hsi = kzalloc(sizeof(*hsi), flags);
+        if (!hsi)
+                return NULL;
+        port = kzalloc(sizeof(*port)*n_ports, flags);
+        if (!port) {
+                kfree(hsi);
+                return NULL;
+        }
+        hsi->num_ports = n_ports;
+        hsi->port = port;
+        hsi->device.release = hsi_controller_release;
+        device_initialize(&hsi->device);
+
+        for (i = 0; i < n_ports; i++) {
+                port[i] = kzalloc(sizeof(**port), flags);
+                if (port[i] == NULL)
+                        goto out;
+                port[i]->num = i;
+                port[i]->async = hsi_dummy_msg;
+                port[i]->setup = hsi_dummy_cl;
+                port[i]->flush = hsi_dummy_cl;
+                port[i]->start_tx = hsi_dummy_cl;
+                port[i]->stop_tx = hsi_dummy_cl;
+                port[i]->release = hsi_dummy_cl;
+                mutex_init(&port[i]->lock);
+                ATOMIC_INIT_NOTIFIER_HEAD(&port[i]->n_head);
+                dev_set_name(&port[i]->device, "port%d", i);
+                hsi->port[i]->device.release = hsi_port_release;
+                device_initialize(&hsi->port[i]->device);
+        }
+
+        return hsi;
+out:
+        hsi_put_controller(hsi);
+
+        return NULL;
+}
+EXPORT_SYMBOL_GPL(hsi_alloc_controller);
+
+/**
+ * hsi_free_msg - Free an HSI message
+ * @msg: Pointer to the HSI message
+ *
+ * Client is responsible to free the buffers pointed by the scatterlists.
+ */
+void hsi_free_msg(struct hsi_msg *msg)
+{
+        if (!msg)
+                return;
+        sg_free_table(&msg->sgt);
+        kfree(msg);
+}
+EXPORT_SYMBOL_GPL(hsi_free_msg);
+
+/**
+ * hsi_alloc_msg - Allocate an HSI message
+ * @nents: Number of memory entries
+ * @flags: Kernel allocation flags
+ *
+ * nents can be 0. This mainly makes sense for read transfer.
+ * In that case, HSI drivers will call the complete callback when
+ * there is data to be read without consuming it.
+ *
+ * Return NULL on failure or a pointer to an hsi_msg on success.
+ */
+struct hsi_msg *hsi_alloc_msg(unsigned int nents, gfp_t flags)
+{
+        struct hsi_msg *msg;
+        int err;
+
+        msg = kzalloc(sizeof(*msg), flags);
+        if (!msg)
+                return NULL;
+
+        if (!nents)
+                return msg;
+
+        err = sg_alloc_table(&msg->sgt, nents, flags);
+        if (unlikely(err)) {
+                kfree(msg);
+                msg = NULL;
+        }
+
+        return msg;
+}
+EXPORT_SYMBOL_GPL(hsi_alloc_msg);
+
+/**
+ * hsi_async - Submit an HSI transfer to the controller
+ * @cl: HSI client sending the transfer
+ * @msg: The HSI transfer passed to controller
+ *
+ * The HSI message must have the channel, ttype, complete and destructor
+ * fields set beforehand. If nents > 0 then the client has to initialize
+ * also the scatterlists to point to the buffers to write to or read from.
+ *
+ * HSI controllers relay on pre-allocated buffers from their clients and they
+ * do not allocate buffers on their own.
+ *
+ * Once the HSI message transfer finishes, the HSI controller calls the
+ * complete callback with the status and actual_len fields of the HSI message
+ * updated. The complete callback can be called before returning from
+ * hsi_async.
+ *
+ * Returns -errno on failure or 0 on success
+ */
+int hsi_async(struct hsi_client *cl, struct hsi_msg *msg)
+{
+        struct hsi_port *port = hsi_get_port(cl);
+
+        if (!hsi_port_claimed(cl))
+                return -EACCES;
+
+        WARN_ON_ONCE(!msg->destructor || !msg->complete);
+        msg->cl = cl;
+
+        return port->async(msg);
+}
+EXPORT_SYMBOL_GPL(hsi_async);
+
+/**
+ * hsi_claim_port - Claim the HSI client's port
+ * @cl: HSI client that wants to claim its port
+ * @share: Flag to indicate if the client wants to share the port or not.
+ *
+ * Returns -errno on failure, 0 on success.
+ */
+int hsi_claim_port(struct hsi_client *cl, unsigned int share)
+{
+        struct hsi_port *port = hsi_get_port(cl);
+        int err = 0;
+
+        mutex_lock(&port->lock);
+        if ((port->claimed) && (!port->shared || !share)) {
+                err = -EBUSY;
+                goto out;
+        }
+        if (!try_module_get(to_hsi_controller(port->device.parent)->owner)) {
+                err = -ENODEV;
+                goto out;
+        }
+        port->claimed++;
+        port->shared = !!share;
+        cl->pclaimed = 1;
+out:
+        mutex_unlock(&port->lock);
+
+        return err;
+}
+EXPORT_SYMBOL_GPL(hsi_claim_port);
+
+/**
+ * hsi_release_port - Release the HSI client's port
+ * @cl: HSI client which previously claimed its port
+ */
+void hsi_release_port(struct hsi_client *cl)
+{
+        struct hsi_port *port = hsi_get_port(cl);
+
+        mutex_lock(&port->lock);
+        /* Allow HW driver to do some cleanup */
+        port->release(cl);
+        if (cl->pclaimed)
+                port->claimed--;
+        BUG_ON(port->claimed < 0);
+        cl->pclaimed = 0;
+        if (!port->claimed)
+                port->shared = 0;
+        module_put(to_hsi_controller(port->device.parent)->owner);
+        mutex_unlock(&port->lock);
+}
+EXPORT_SYMBOL_GPL(hsi_release_port);
+
+static int hsi_event_notifier_call(struct notifier_block *nb,
+                                unsigned long event, void *data __maybe_unused)
+{
+        struct hsi_client *cl = container_of(nb, struct hsi_client, nb);
+
+        (*cl->ehandler)(cl, event);
+
+        return 0;
+}
+
+/**
+ * hsi_register_port_event - Register a client to receive port events
+ * @cl: HSI client that wants to receive port events
+ * @cb: Event handler callback
+ *
+ * Clients should register a callback to be able to receive
+ * events from the ports. Registration should happen after
+ * claiming the port.
+ * The handler can be called in interrupt context.
+ *
+ * Returns -errno on error, or 0 on success.
+ */
+int hsi_register_port_event(struct hsi_client *cl,
+                        void (*handler)(struct hsi_client *, unsigned long))
+{
+        struct hsi_port *port = hsi_get_port(cl);
+
+        if (!handler || cl->ehandler)
+                return -EINVAL;
+        if (!hsi_port_claimed(cl))
+                return -EACCES;
+        cl->ehandler = handler;
+        cl->nb.notifier_call = hsi_event_notifier_call;
+
+        return atomic_notifier_chain_register(&port->n_head, &cl->nb);
+}
+EXPORT_SYMBOL_GPL(hsi_register_port_event);
+
+/**
+ * hsi_unregister_port_event - Stop receiving port events for a client
+ * @cl: HSI client that wants to stop receiving port events
+ *
+ * Clients should call this function before releasing their associated
+ * port.
+ *
+ * Returns -errno on error, or 0 on success.
+ */
+int hsi_unregister_port_event(struct hsi_client *cl)
+{
+        struct hsi_port *port = hsi_get_port(cl);
+        int err;
+
+        WARN_ON(!hsi_port_claimed(cl));
+
+        err = atomic_notifier_chain_unregister(&port->n_head, &cl->nb);
+        if (!err)
+                cl->ehandler = NULL;
+
+        return err;
+}
+EXPORT_SYMBOL_GPL(hsi_unregister_port_event);
+
+/**
+ * hsi_event -Notifies clients about port events
+ * @port: Port where the event occurred
+ * @event: The event type
+ *
+ * Clients should not be concerned about wake line behavior. However, due
+ * to a race condition in HSI HW protocol, clients need to be notified
+ * about wake line changes, so they can implement a workaround for it.
+ *
+ * Events:
+ * HSI_EVENT_START_RX - Incoming wake line high
+ * HSI_EVENT_STOP_RX - Incoming wake line down
+ *
+ * Returns -errno on error, or 0 on success.
+ */
+int hsi_event(struct hsi_port *port, unsigned long event)
+{
+        return atomic_notifier_call_chain(&port->n_head, event, NULL);
+}
+EXPORT_SYMBOL_GPL(hsi_event);
+
+static int __init hsi_init(void)
+{
+        return bus_register(&hsi_bus_type);
+}
+postcore_initcall(hsi_init);
+
+static void __exit hsi_exit(void)
+{
+        bus_unregister(&hsi_bus_type);
+}
+module_exit(hsi_exit);
+
+MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
+MODULE_DESCRIPTION("High-speed Synchronous Serial Interface (HSI) framework");
+MODULE_LICENSE("GPL v2");