Re: [U-Boot] [PATCH 08/12] dm: stdio: Allow lazy probing of video devices

Hi Simon,

On Mon, Oct 3, 2016 at 11:12 AM, Simon Glass sjg@chromium.org wrote:

At present all video devices are probed on start-up. It would be better to probe a device only when it is needed. This can happen if it is referenced in the stdout environment variable, for example.

Add support for this by searching for a suitable device when needed, probing it, and finding the stdio device it creates.

Signed-off-by: Simon Glass sjg@chromium.org

common/stdio.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 63 insertions(+), 4 deletions(-)

diff --git a/common/stdio.c b/common/stdio.c index f99cfe7..b58b3c7 100644 --- a/common/stdio.c +++ b/common/stdio.c @@ -121,19 +121,76 @@ struct list_head* stdio_get_list(void) return &(devs.list); }

+#ifdef CONFIG_DM_VIDEO +/**

• • stdio_probe_device() - Find a device which provides the given stdio device
• • This looks for a device of the given uclass which provides a particular
• • stdio device. It is currently really only useful for UCLASS_VIDEO.
• • Ultimately we want to be able to probe a device by its stdio name. At
• • present devices register in their probe function (for video devices this
• • is done in vidconsole_post_probe()) and we don't know what name they will
• • use until they do so.
• • TODO(sjg@chromium.org): We should be able to determine the name before
• • probing, and probe the required device.
• • @name: stdio device name (e.g. "vidconsole")
• • id: Uclass ID of device to look for (e.g. UCLASS_VIDEO)
• • @sdevp: Returns stdout device, if found, else NULL
• • @return 0 if found, -ENOENT if no device found with that name, other -ve

• •    on other error
    

• */

+static int stdio_probe_device(const char *name, enum uclass_id id,

•                         struct stdio_dev **sdevp)
  

+{

•   struct stdio_dev *sdev;
  

•   struct udevice *dev;
  

•   int seq, ret;
  

•   *sdevp = NULL;
  

•   seq = trailing_strtoln(name, NULL);
  

•   if (seq == -1)
  

•           ret = uclass_first_device_err(id, &dev);
  

•   else
  

•           ret = uclass_get_device_by_seq(id, seq, &dev);
  

•   if (ret) {
  

•           debug("No %s device for seq %d (%s)\n", uclass_get_name(id),
  

•                 seq, name);
  

•           return ret;
  

•   }
  

•   /* The device should be be the last one registered */
  

•   sdev = list_empty(&devs.list) ? NULL :
  

•                   list_last_entry(&devs.list, struct stdio_dev, list);
  

•   if (!sdev || strcmp(sdev->name, name)) {
  

•           debug("Device '%s' did not register with stdio as '%s'\n",
  

•                 dev->name, name);
  

•           return -ENOENT;
  

•   }
  

•   *sdevp = sdev;
  

•   return 0;
  

+} +#endif

struct stdio_dev* stdio_get_by_name(const char *name) { struct list_head *pos;

•   struct stdio_dev *dev;
  

•   struct stdio_dev *sdev;
  
    if(!name)
            return NULL;
  
    list_for_each(pos, &(devs.list)) {
  

•           dev = list_entry(pos, struct stdio_dev, list);
  

•           if(strcmp(dev->name, name) == 0)
  

•                   return dev;
  

•           sdev = list_entry(pos, struct stdio_dev, list);
  

•           if (strcmp(sdev->name, name) == 0)
  

•                   return sdev;
    }
  

+#ifdef CONFIG_DM_VIDEO

•   if (!strncmp(name, "vidconsole", 10) && !strchr(name, ',') &&
  

Why is strchr(name, ',') needed?

•       !stdio_probe_device(name, UCLASS_VIDEO, &sdev))
  

•           return sdev;
  

+#endif

    return NULL;

} @@ -282,6 +339,7 @@ int stdio_add_devices(void) #endif #endif #ifdef CONFIG_DM_VIDEO +#ifndef CONFIG_SYS_CONSOLE_IS_IN_ENV

Wy adding CONFIG_SYS_CONSOLE_IS_IN_ENV check?

    struct udevice *vdev;

# ifndef CONFIG_DM_KEYBOARD int ret; @@ -293,6 +351,7 @@ int stdio_add_devices(void) ; if (ret) printf("%s: Video device failed (ret=%d)\n", __func__, ret); +#endif /* !CONFIG_SYS_CONSOLE_IS_IN_ENV */ #else # if defined(CONFIG_LCD) drv_lcd_init (); --

Regards, Bin