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Date: Wed, 05 Jun 2013 09:10:05 +0200
From: Takashi Iwai <tiwai@...e.de>
To: Ming Lei <ming.lei@...onical.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
linux-kernel@...r.kernel.org,
Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 3/3] firmware loader: allow distribution to choose default search paths
At Wed, 5 Jun 2013 13:42:49 +0800,
Ming Lei wrote:
>
> For some distributions(e.g. android), firmware images aren't put
> under kernel built-in search paths, so introduce one Kconfig
> option to allow distributions or users to choose its specific default
> search paths, which are always tried before searching from kernel
> built-in paths in direct loading.
>
> Cc: Linus Torvalds <torvalds@...ux-foundation.org>
> Cc: Takashi Iwai <tiwai@...e.de>
> Signed-off-by: Ming Lei <ming.lei@...onical.com>
> ---
> drivers/base/Kconfig | 12 +++++++
> drivers/base/firmware_class.c | 76 ++++++++++++++++++++++++++++++++++++-----
> 2 files changed, 80 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
> index 07abd9d..5b0c909 100644
> --- a/drivers/base/Kconfig
> +++ b/drivers/base/Kconfig
> @@ -156,6 +156,18 @@ config FW_LOADER_USER_HELPER
> no longer required unless you have a special firmware file that
> resides in a non-standard path.
>
> +config FW_CUSTOMIZED_PATH
> + string "default firmware search paths for direct loading"
> + help
> + On some distribution(e.g. android), firmware images aren't
> + put under kernel built-in search paths, so provide this option
> + for distributions to choose a distribution specific firmware
> + search path. The option allows to choose more than one path,
> + and paths are seperated with semicolon(e.g. on android, the
> + option might look as "/etc/firmware;/vendor/firmware").
> +
> + If you are unsure about this, don't choose here.
> +
> config DEBUG_DRIVER
> bool "Driver Core verbose debug messages"
> depends on DEBUG_KERNEL
> diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
> index c743409..50b5913 100644
> --- a/drivers/base/firmware_class.c
> +++ b/drivers/base/firmware_class.c
> @@ -267,6 +267,9 @@ static void fw_free_buf(struct firmware_buf *buf)
> static char fw_path_para[256];
> static const char * const fw_path[] = {
> fw_path_para,
> +#ifdef CONFIG_FW_CUSTOMIZED_PATH
> + CONFIG_FW_CUSTOMIZED_PATH,
> +#endif
> "/lib/firmware/updates/" UTS_RELEASE,
> "/lib/firmware/updates",
> "/lib/firmware/" UTS_RELEASE,
> @@ -314,6 +317,59 @@ static bool fw_read_file_contents(struct file *file, struct firmware_buf *fw_buf
> return true;
> }
>
> +static bool fw_get_file_firmware(const char *path,
> + struct firmware_buf *buf)
> +{
> + struct file *file;
> + bool success;
> +
> + file = filp_open(path, O_RDONLY, 0);
> + if (IS_ERR(file))
> + return false;
> + success = fw_read_file_contents(file, buf);
> + fput(file);
> +
> + return success;
> +}
> +
> +#ifdef CONFIG_FW_CUSTOMIZED_PATH
> +/* The path in @paths is seperated by ';' */
> +static bool fw_get_fw_file_from_paths(const char *paths, char *path,
> + struct firmware_buf *buf)
> +{
> + int len, start, end;
> + char *pos;
> +
> + end = -1;
> + do {
> + start = end + 1;
> + pos = strchr(&paths[start], ';');
> + if (pos) {
> + end = (int)(pos - paths);
> + len = end - start;
> + } else {
> + len = strlen(&paths[start]);
> + }
> +
> + if (PATH_MAX < len + strlen(buf->fw_id))
> + continue;
> + strncpy(path, &paths[start], len);
> + snprintf(&path[len], PATH_MAX - len, "/%s", buf->fw_id);
> +
> + if (fw_get_file_firmware(path, buf))
> + return true;
> + } while (pos && end < strlen(paths) - 1);
> +
> + return false;
> +}
> +#else
> +static bool fw_get_fw_file_from_paths(const char *paths, char *path,
> + struct firmware_buf *buf)
> +{
> + return false;
> +}
> +#endif
> +
> static bool fw_get_filesystem_firmware(struct device *device,
> struct firmware_buf *buf)
> {
> @@ -322,19 +378,23 @@ static bool fw_get_filesystem_firmware(struct device *device,
> char *path = __getname();
>
> for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
> - struct file *file;
>
> /* skip the unset customized path */
> if (!fw_path[i][0])
> continue;
>
> - snprintf(path, PATH_MAX, "%s/%s", fw_path[i], buf->fw_id);
> -
> - file = filp_open(path, O_RDONLY, 0);
> - if (IS_ERR(file))
> - continue;
> - success = fw_read_file_contents(file, buf);
> - fput(file);
> + /*
> + * If CONFIG_FW_CUSTOMIZED_PATH is set, search from
> + * these paths first
> + */
> + if (i == 1 && ARRAY_SIZE(fw_path) > 5) {
> + success = fw_get_fw_file_from_paths(fw_path[1],
> + path, buf);
> + } else {
> + snprintf(path, PATH_MAX, "%s/%s", fw_path[i],
> + buf->fw_id);
> + success = fw_get_file_firmware(path, buf);
Shouldn't fw_get_fw_file_from_paths() be applied unconditionally?
It'll be benefit for the customized path passed via module option,
too. The only drawback is a slight code growth, but the code can be
reduced a bit with strcspn() or such.
BTW, I now wonder what happens if you pass a relative path.
Did you already test it?
thanks,
Takashi
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