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Message-ID: <alpine.DEB.2.20.1703100940340.2460@mgerlach-VirtualBox>
Date: Fri, 10 Mar 2017 09:44:12 -0800 (PST)
From: matthew.gerlach@...ux.intel.com
To: Yi Li <yi1.li@...ux.intel.com>
cc: ming.lei@...onical.com, mcgrof@...nel.org,
gregkh@...uxfoundation.org, atull@...nsource.altera.com,
moritz.fischer@...us.com, linux-kernel@...r.kernel.org,
linux-fpga@...r.kernel.org
Subject: Re: [RFC 1/2] firmware class: Add stream_firmware API.
On Thu, 9 Mar 2017, yi1.li@...ux.intel.com wrote:
> From: Yi Li <yi1.li@...ux.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@...ux.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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