stm class: Switch over to the protocol driver

Now that the default framing protocol is factored out into its own driver,
switch over to using the driver for writing data. To that end, make the
policy code require a valid protocol name (or absence thereof, which is
equivalent to "p_basic").

Also, to make transition easier, make stm class request "p_basic" module
at initialization time.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c
index b789a5f0688e178ee0f9ee4bc3bc23d950a87391..93ce3aa740a92f3bc14193bd26e88a3661d43ab3 100644 (file)
--- a/drivers/hwtracing/stm/core.c
+++ b/drivers/hwtracing/stm/core.c
@@ -603,18 +603,21 @@ ssize_t notrace stm_data_write(struct stm_data *data, unsigned int m,
 }
 EXPORT_SYMBOL_GPL(stm_data_write);
 
-static ssize_t notrace stm_write(struct stm_data *data, unsigned int master,
-                         unsigned int channel, const char *buf, size_t count)
+static ssize_t notrace
+stm_write(struct stm_device *stm, struct stm_output *output,
+         unsigned int chan, const char *buf, size_t count)
 {
-       const unsigned char nil = 0;
-       ssize_t sz;
+       int err;
+
+       /* stm->pdrv is serialized against policy_mutex */
+       if (!stm->pdrv)
+               return -ENODEV;
 
-       sz = stm_data_write(data, master, channel, true, buf, count);
-       if (sz > 0)
-               data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0,
-                            &nil);
+       err = stm->pdrv->write(stm->data, output, chan, buf, count);
+       if (err < 0)
+               return err;
 
-       return sz;
+       return err;
 }
 
 static ssize_t stm_char_write(struct file *file, const char __user *buf,
@@ -659,8 +662,7 @@ static ssize_t stm_char_write(struct file *file, const char __user *buf,
 
        pm_runtime_get_sync(&stm->dev);
 
-       count = stm_write(stm->data, stmf->output.master, stmf->output.channel,
-                         kbuf, count);
+       count = stm_write(stm, &stmf->output, 0, kbuf, count);
 
        pm_runtime_mark_last_busy(&stm->dev);
        pm_runtime_put_autosuspend(&stm->dev);
@@ -1310,9 +1312,7 @@ int notrace stm_source_write(struct stm_source_data *data,
 
        stm = srcu_dereference(src->link, &stm_source_srcu);
        if (stm)
-               count = stm_write(stm->data, src->output.master,
-                                 src->output.channel + chan,
-                                 buf, count);
+               count = stm_write(stm, &src->output, chan, buf, count);
        else
                count = -ENODEV;
 
@@ -1342,6 +1342,12 @@ static int __init stm_core_init(void)
        INIT_LIST_HEAD(&stm_pdrv_head);
        mutex_init(&stm_pdrv_mutex);
 
+       /*
+        * So as to not confuse existing users with a requirement
+        * to load yet another module, do it here.
+        */
+       if (IS_ENABLED(CONFIG_STM_PROTO_BASIC))
+               (void)request_module_nowait("stm_p_basic");
        stm_core_up++;
 
        return 0;

diff --git a/drivers/hwtracing/stm/policy.c b/drivers/hwtracing/stm/policy.c
index 8bc90432ae69b7ee5e44543ac561cf2dd2c60d74..5e51bed0787b18e885acbfe58a23ff8c543853c8 100644 (file)
--- a/drivers/hwtracing/stm/policy.c
+++ b/drivers/hwtracing/stm/policy.c
@@ -454,8 +454,7 @@ stp_policy_make(struct config_group *group, const char *name)
        err = stm_lookup_protocol(proto, &pdrv, &pdrv_node_type);
        kfree(devname);
 
-       /* We don't have any protocol drivers yet */
-       if (err != -ENOENT) {
+       if (err) {
                stm_put_device(stm);
                return ERR_PTR(-ENODEV);
        }