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    SubjectRe: [RFC 1/2] firmware class: Add stream_firmware API.


    On Thu, 9 Mar 2017, yi1.li@linux.intel.com wrote:

    > From: Yi Li <yi1.li@linux.intel.com>


    Hi Yi,

    Just one question below.

    Matthew Gerlach


    > Add function to load firmware in multiple chucks instead of
    >
    > loading the whole big firmware file at once.
    >
    > Signed-off-by: Yi Li <yi1.li@linux.intel.com>
    > ---
    > drivers/base/firmware_class.c | 128 ++++++++++++++++++++++++++++++++++++++++++
    > include/linux/firmware.h | 2 +
    > 2 files changed, 130 insertions(+)
    >
    > diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
    > index ac350c5..44fddff 100644
    > --- a/drivers/base/firmware_class.c
    > +++ b/drivers/base/firmware_class.c
    > @@ -436,6 +436,62 @@ fw_get_filesystem_firmware(struct device *device, struct firmware_buf *buf)
    > return rc;
    > }
    >
    > +static int
    > +fw_stream_filesystem_firmware(struct device *device, struct firmware_buf *buf,
    > + size_t offset, size_t length)
    > +{
    > + int i, len;
    > + char *path;
    > + int rc = 0;
    > + struct file *file;
    > +
    > + buf->size = 0;
    > +
    > + path = __getname();
    > + if (!path)
    > + return -ENOMEM;
    > +
    > + for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
    > + /* skip the unset customized path */
    > + if (!fw_path[i][0])
    > + continue;
    > +
    > + len = snprintf(path, PATH_MAX, "%s/%s",
    > + fw_path[i], buf->fw_id);

    I'm probably being paranoid, but is it safe to assume the length of the
    buffer returned by __getname() is at least PATH_MAX? It seems like
    the length should be pagesize.

    > + if (len >= PATH_MAX) {
    > + rc = -ENAMETOOLONG;
    > + break;
    > + }
    > +
    > + if (!path || !*path)
    > + continue;
    > +
    > + if (!buf->data) {
    > + buf->data = vmalloc(length);
    > + if (!buf->data) {
    > + rc = -ENOMEM;
    > + break;
    > + }
    > + }
    > +
    > + file = filp_open(path, O_RDONLY, 0);
    > + if (IS_ERR(file))
    > + continue;
    > +
    > + buf->size = kernel_read(file, offset, (char *) buf->data,
    > + length);
    > + fput(file);
    > + break;
    > + }
    > +
    > + __putname(path);
    > +
    > + if (rc)
    > + dev_err(device, "loading %s failed with error %d\n",
    > + path, rc);
    > + return rc;
    > +}
    > +
    > /* firmware holds the ownership of pages */
    > static void firmware_free_data(const struct firmware *fw)
    > {
    > @@ -1267,6 +1323,78 @@ request_firmware(const struct firmware **firmware_p, const char *name,
    > }
    > EXPORT_SYMBOL(request_firmware);
    >
    > +static int
    > +_stream_firmware(const struct firmware **firmware_p, const char *name,
    > + struct device *device, void *buf, size_t size,
    > + unsigned int opt_flags, size_t offset, size_t length)
    > +{
    > + int ret;
    > + struct firmware *fw = NULL;
    > + struct firmware_buf *fbuf;
    > +
    > + if ((!firmware_p) || (!name || name[0] == '\0')) {
    > + dev_err(device, "invalid firmware pointer or file name\n");
    > + return -EINVAL;
    > + }
    > +
    > + if (!*firmware_p) {
    > + ret = _request_firmware_prepare(&fw, name, device, buf, size);
    > + if (ret <= 0) {
    > + dev_err(device, "%s: _request_firmware_prepare failed %d\n",
    > + __func__, ret);
    > + }
    > + } else {
    > + fw = (struct firmware *) *firmware_p;
    > + }
    > +
    > + fbuf = (struct firmware_buf *) fw->priv;
    > + ret = fw_stream_filesystem_firmware(device, fbuf, offset, length);
    > + fw->size = fbuf->size;
    > + fw->data = fbuf->data;
    > + *firmware_p = fw;
    > +
    > + if (ret)
    > + dev_err(device, "streaming with error %d\n", ret);
    > + return ret;
    > +}
    > +
    > +/**
    > + * stream_firmware: - send firmware request and wait for it
    > + * @firmware_p: pointer to firmware image
    > + * @name: name of firmware file
    > + * @device: device for which firmware is being loaded
    > + * @offset: offset of the file to read from
    > + * @length: length in bytes to read
    > + *
    > + * @firmware_p will be used to return a firmware image by the name
    > + * of @name for device @device.
    > + *
    > + * Should be called from user context where sleeping is allowed.
    > + *
    > + * @name will be used as $FIRMWARE in the uevent environment and
    > + * should be distinctive enough not to be confused with any other
    > + * firmware image for this or any other device.
    > + *
    > + * Caller must hold the reference count of @device.
    > + *
    > + * The function can be called safely inside device's suspend and
    > + * resume callback.
    > + **/
    > +int
    > +stream_firmware(const struct firmware **firmware_p, const char *name,
    > + struct device *device, size_t offset, size_t length)
    > +{
    > + size_t ret;
    > +
    > + /* Need to pin this module until return */
    > + __module_get(THIS_MODULE);
    > + ret = _stream_firmware(firmware_p, name, device, NULL, 0,
    > + FW_OPT_UEVENT | FW_OPT_NO_WARN, offset, length);
    > + module_put(THIS_MODULE);
    > + return ret;
    > +}
    > +EXPORT_SYMBOL(stream_firmware);
    > +
    > /**
    > * request_firmware_direct: - load firmware directly without usermode helper
    > * @firmware_p: pointer to firmware image
    > diff --git a/include/linux/firmware.h b/include/linux/firmware.h
    > index b1f9f0c..accd7f6 100644
    > --- a/include/linux/firmware.h
    > +++ b/include/linux/firmware.h
    > @@ -41,6 +41,8 @@ struct builtin_fw {
    > #if defined(CONFIG_FW_LOADER) || (defined(CONFIG_FW_LOADER_MODULE) && defined(MODULE))
    > int request_firmware(const struct firmware **fw, const char *name,
    > struct device *device);
    > +int stream_firmware(const struct firmware **fw, const char *name,
    > + struct device *device, size_t offset, size_t length);
    > int request_firmware_nowait(
    > struct module *module, bool uevent,
    > const char *name, struct device *device, gfp_t gfp, void *context,
    > --
    > 2.7.4
    >
    > --
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