Add offset to request_firmware_into_buf to allow for portions
of firmware file to be read into a buffer.  Necessary where firmware
needs to be loaded in portions from file in memory constrained systems.

Signed-off-by: Scott Branden <scott.bran...@broadcom.com>
---
 drivers/base/firmware_loader/firmware.h |  5 +++
 drivers/base/firmware_loader/main.c     | 49 +++++++++++++++++--------
 include/linux/firmware.h                |  8 +++-
 3 files changed, 45 insertions(+), 17 deletions(-)

diff --git a/drivers/base/firmware_loader/firmware.h 
b/drivers/base/firmware_loader/firmware.h
index 4c1395f8e7ed..d73d400c2023 100644
--- a/drivers/base/firmware_loader/firmware.h
+++ b/drivers/base/firmware_loader/firmware.h
@@ -29,6 +29,8 @@
  *     firmware caching mechanism.
  * @FW_OPT_NOFALLBACK: Disable the fallback mechanism. Takes precedence over
  *     &FW_OPT_UEVENT and &FW_OPT_USERHELPER.
+ * @FW_OPT_PARTIAL: Allow partial read of firmware instead of needing to read
+ *     entire file.
  */
 enum fw_opt {
        FW_OPT_UEVENT =         BIT(0),
@@ -37,6 +39,7 @@ enum fw_opt {
        FW_OPT_NO_WARN =        BIT(3),
        FW_OPT_NOCACHE =        BIT(4),
        FW_OPT_NOFALLBACK =     BIT(5),
+       FW_OPT_PARTIAL =        BIT(6),
 };
 
 enum fw_status {
@@ -64,6 +67,8 @@ struct fw_priv {
        void *data;
        size_t size;
        size_t allocated_size;
+       size_t offset;
+       unsigned int flags;
 #ifdef CONFIG_FW_LOADER_USER_HELPER
        bool is_paged_buf;
        bool need_uevent;
diff --git a/drivers/base/firmware_loader/main.c 
b/drivers/base/firmware_loader/main.c
index 7eaaf5ee5ba6..34d4f043b7c8 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -166,7 +166,8 @@ static int fw_cache_piggyback_on_request(const char *name);
 
 static struct fw_priv *__allocate_fw_priv(const char *fw_name,
                                          struct firmware_cache *fwc,
-                                         void *dbuf, size_t size)
+                                         void *dbuf, size_t size,
+                                         size_t offset, unsigned int flags)
 {
        struct fw_priv *fw_priv;
 
@@ -184,6 +185,8 @@ static struct fw_priv *__allocate_fw_priv(const char 
*fw_name,
        fw_priv->fwc = fwc;
        fw_priv->data = dbuf;
        fw_priv->allocated_size = size;
+       fw_priv->offset = offset;
+       fw_priv->flags = flags;
        fw_state_init(fw_priv);
 #ifdef CONFIG_FW_LOADER_USER_HELPER
        INIT_LIST_HEAD(&fw_priv->pending_list);
@@ -209,9 +212,11 @@ static struct fw_priv *__lookup_fw_priv(const char 
*fw_name)
 static int alloc_lookup_fw_priv(const char *fw_name,
                                struct firmware_cache *fwc,
                                struct fw_priv **fw_priv, void *dbuf,
-                               size_t size, enum fw_opt opt_flags)
+                               size_t size, enum fw_opt opt_flags,
+                               size_t offset)
 {
        struct fw_priv *tmp;
+       unsigned int pread_flags;
 
        spin_lock(&fwc->lock);
        if (!(opt_flags & FW_OPT_NOCACHE)) {
@@ -225,7 +230,12 @@ static int alloc_lookup_fw_priv(const char *fw_name,
                }
        }
 
-       tmp = __allocate_fw_priv(fw_name, fwc, dbuf, size);
+       if (opt_flags & FW_OPT_PARTIAL)
+               pread_flags = KERNEL_PREAD_FLAG_PART;
+       else
+               pread_flags = KERNEL_PREAD_FLAG_WHOLE;
+
+       tmp = __allocate_fw_priv(fw_name, fwc, dbuf, size, offset, pread_flags);
        if (tmp) {
                INIT_LIST_HEAD(&tmp->list);
                if (!(opt_flags & FW_OPT_NOCACHE))
@@ -325,8 +335,9 @@ fw_get_filesystem_firmware(struct device *device, struct 
fw_priv *fw_priv)
                }
 
                fw_priv->size = 0;
-               rc = kernel_read_file_from_path(path, &fw_priv->data, &size,
-                                               msize, id);
+               rc = kernel_pread_file_from_path(path, &fw_priv->data, &size,
+                                                fw_priv->offset, msize,
+                                                fw_priv->flags, id);
                if (rc) {
                        if (rc != -ENOENT)
                                dev_warn(device, "loading %s failed with error 
%d\n",
@@ -500,7 +511,7 @@ int assign_fw(struct firmware *fw, struct device *device,
 static int
 _request_firmware_prepare(struct firmware **firmware_p, const char *name,
                          struct device *device, void *dbuf, size_t size,
-                         enum fw_opt opt_flags)
+                         enum fw_opt opt_flags, size_t offset)
 {
        struct firmware *firmware;
        struct fw_priv *fw_priv;
@@ -519,7 +530,7 @@ _request_firmware_prepare(struct firmware **firmware_p, 
const char *name,
        }
 
        ret = alloc_lookup_fw_priv(name, &fw_cache, &fw_priv, dbuf, size,
-                                 opt_flags);
+                                 opt_flags, offset);
 
        /*
         * bind with 'priv' now to avoid warning in failure path
@@ -566,7 +577,7 @@ static void fw_abort_batch_reqs(struct firmware *fw)
 static int
 _request_firmware(const struct firmware **firmware_p, const char *name,
                  struct device *device, void *buf, size_t size,
-                 enum fw_opt opt_flags)
+                 enum fw_opt opt_flags, size_t offset)
 {
        struct firmware *fw = NULL;
        int ret;
@@ -580,7 +591,7 @@ _request_firmware(const struct firmware **firmware_p, const 
char *name,
        }
 
        ret = _request_firmware_prepare(&fw, name, device, buf, size,
-                                       opt_flags);
+                                       opt_flags, offset);
        if (ret <= 0) /* error or already assigned */
                goto out;
 
@@ -634,7 +645,7 @@ request_firmware(const struct firmware **firmware_p, const 
char *name,
        /* Need to pin this module until return */
        __module_get(THIS_MODULE);
        ret = _request_firmware(firmware_p, name, device, NULL, 0,
-                               FW_OPT_UEVENT);
+                               FW_OPT_UEVENT, 0);
        module_put(THIS_MODULE);
        return ret;
 }
@@ -661,7 +672,7 @@ int firmware_request_nowarn(const struct firmware 
**firmware, const char *name,
        /* Need to pin this module until return */
        __module_get(THIS_MODULE);
        ret = _request_firmware(firmware, name, device, NULL, 0,
-                               FW_OPT_UEVENT | FW_OPT_NO_WARN);
+                               FW_OPT_UEVENT | FW_OPT_NO_WARN, 0);
        module_put(THIS_MODULE);
        return ret;
 }
@@ -686,7 +697,7 @@ int request_firmware_direct(const struct firmware 
**firmware_p,
        __module_get(THIS_MODULE);
        ret = _request_firmware(firmware_p, name, device, NULL, 0,
                                FW_OPT_UEVENT | FW_OPT_NO_WARN |
-                               FW_OPT_NOFALLBACK);
+                               FW_OPT_NOFALLBACK, 0);
        module_put(THIS_MODULE);
        return ret;
 }
@@ -723,6 +734,8 @@ EXPORT_SYMBOL_GPL(firmware_request_cache);
  * @device: device for which firmware is being loaded and DMA region allocated
  * @buf: address of buffer to load firmware into
  * @size: size of buffer
+ * @offset: offset into file to read
+ * @pread_flags: KERNEL_PREAD_FLAG_PART to allow partial file read
  *
  * This function works pretty much like request_firmware(), but it doesn't
  * allocate a buffer to hold the firmware data. Instead, the firmware
@@ -733,16 +746,22 @@ EXPORT_SYMBOL_GPL(firmware_request_cache);
  */
 int
 request_firmware_into_buf(const struct firmware **firmware_p, const char *name,
-                         struct device *device, void *buf, size_t size)
+                         struct device *device, void *buf, size_t size,
+                         size_t offset, unsigned int pread_flags)
 {
        int ret;
+       enum fw_opt opt_flags;
 
        if (fw_cache_is_setup(device, name))
                return -EOPNOTSUPP;
 
        __module_get(THIS_MODULE);
+       opt_flags = FW_OPT_UEVENT | FW_OPT_NOCACHE;
+       if (pread_flags & KERNEL_PREAD_FLAG_PART)
+               opt_flags |= FW_OPT_PARTIAL;
+
        ret = _request_firmware(firmware_p, name, device, buf, size,
-                               FW_OPT_UEVENT | FW_OPT_NOCACHE);
+                               opt_flags, offset);
        module_put(THIS_MODULE);
        return ret;
 }
@@ -781,7 +800,7 @@ static void request_firmware_work_func(struct work_struct 
*work)
        fw_work = container_of(work, struct firmware_work, work);
 
        _request_firmware(&fw, fw_work->name, fw_work->device, NULL, 0,
-                         fw_work->opt_flags);
+                         fw_work->opt_flags, 0);
        fw_work->cont(fw, fw_work->context);
        put_device(fw_work->device); /* taken in request_firmware_nowait() */
 
diff --git a/include/linux/firmware.h b/include/linux/firmware.h
index 2dd566c91d44..c81162a8d709 100644
--- a/include/linux/firmware.h
+++ b/include/linux/firmware.h
@@ -4,6 +4,7 @@
 
 #include <linux/types.h>
 #include <linux/compiler.h>
+#include <linux/fs.h>
 #include <linux/gfp.h>
 
 #define FW_ACTION_NOHOTPLUG 0
@@ -51,7 +52,9 @@ int request_firmware_nowait(
 int request_firmware_direct(const struct firmware **fw, const char *name,
                            struct device *device);
 int request_firmware_into_buf(const struct firmware **firmware_p,
-       const char *name, struct device *device, void *buf, size_t size);
+                             const char *name, struct device *device,
+                             void *buf, size_t size,
+                             size_t offset, unsigned int pread_flags);
 
 void release_firmware(const struct firmware *fw);
 #else
@@ -89,7 +92,8 @@ static inline int request_firmware_direct(const struct 
firmware **fw,
 }
 
 static inline int request_firmware_into_buf(const struct firmware **firmware_p,
-       const char *name, struct device *device, void *buf, size_t size)
+       const char *name, struct device *device, void *buf, size_t size,
+       size_t offset, unsigned int pread_flags);
 {
        return -EINVAL;
 }
-- 
2.17.1

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