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Subject[RFC PATCH 07/13] driver core: firmware loader: introduce cache_firmware and uncache_firmware
Date
This patches introduce two kernel APIs of cache_firmware and
uncache_firmware, both of which take the firmware file name
as the only parameter.

So any drivers can call cache_firmware to cache the specified
firmware file into kernel memory, and can use the cached firmware
in situations which can't request firmware from user space.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
drivers/base/firmware_class.c | 79 +++++++++++++++++++++++++++++++++++++++++
include/linux/firmware.h | 12 +++++++
2 files changed, 91 insertions(+)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 225898e..674cb11 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -168,6 +168,22 @@ static int fw_lookup_and_alloate_buf(const char *fw_name,
return tmp ? 0 : -1;
}

+static struct firmware_buf *fw_lookup_buf(const char *fw_name)
+{
+ struct firmware_buf *tmp;
+ struct firmware_cache *fwc = &fw_cache;
+
+ spin_lock(&fwc->lock);
+ list_for_each_entry(tmp, &fwc->head, list)
+ if (!strcmp(tmp->fw_id, fw_name)) {
+ spin_unlock(&fwc->lock);
+ return tmp;
+ }
+ spin_unlock(&fwc->lock);
+
+ return NULL;
+}
+
static void __fw_free_buf(struct kref *ref)
{
struct firmware_buf *buf = to_fwbuf(ref);
@@ -833,6 +849,67 @@ request_firmware_nowait(
return 0;
}

+/**
+ * cache_firmware - cache one firmware image in kernel memory space
+ * @fw_name: the firmware image name
+ *
+ * Cache firmware in kernel memory so that drivers can use the firmware
+ * when system isn't ready for drivers to request firmware image from
+ * userspace. Once returns successfully, driver can use request_firmware*
+ * to get the cached firmware without any interacting with user space
+ *
+ * Return 0 if the firmware image has been cached successfully
+ * Return !0 if it is not successfully
+ *
+ */
+int cache_firmware(const char *fw_name)
+{
+ int ret;
+ const struct firmware *fw;
+
+ pr_debug("%s: %s\n", __func__, fw_name);
+
+ ret = request_firmware(&fw, fw_name, NULL);
+
+ if (!ret)
+ kfree(fw);
+
+ pr_debug("%s: %s ret=%d\n", __func__, fw_name, ret);
+
+ return ret;
+}
+
+/**
+ * uncache_firmware - remove one cached firmware image
+ *
+ * @fw_name: the firmware image name
+ *
+ * Uncache one firmware image which has been cached successfully
+ * before.
+ *
+ * Return 0 if the firmware cache has been removed successfully
+ * Return !0 if it is not successfully
+ *
+ */
+int uncache_firmware(const char *fw_name)
+{
+ struct firmware_buf *buf;
+ struct firmware fw;
+
+ pr_debug("%s: %s\n", __func__, fw_name);
+
+ if (fw_get_builtin_firmware(&fw, fw_name))
+ return 0;
+
+ buf = fw_lookup_buf(fw_name);
+ if (buf) {
+ fw_free_buf(buf);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
static int __init firmware_class_init(void)
{
fw_cache_init();
@@ -850,3 +927,5 @@ module_exit(firmware_class_exit);
EXPORT_SYMBOL(release_firmware);
EXPORT_SYMBOL(request_firmware);
EXPORT_SYMBOL(request_firmware_nowait);
+EXPORT_SYMBOL_GPL(cache_firmware);
+EXPORT_SYMBOL_GPL(uncache_firmware);
diff --git a/include/linux/firmware.h b/include/linux/firmware.h
index e85b771..1bfa202 100644
--- a/include/linux/firmware.h
+++ b/include/linux/firmware.h
@@ -47,6 +47,8 @@ int request_firmware_nowait(
void (*cont)(const struct firmware *fw, void *context));

void release_firmware(const struct firmware *fw);
+int cache_firmware(const char *name);
+int uncache_firmware(const char *name);
#else
static inline int request_firmware(const struct firmware **fw,
const char *name,
@@ -65,6 +67,16 @@ static inline int request_firmware_nowait(
static inline void release_firmware(const struct firmware *fw)
{
}
+
+int cache_firmware(const char *name)
+{
+ return -ENOENT;
+}
+
+int uncache_firmware(const char *name)
+{
+ return -EINVAL;
+}
#endif

#endif
--
1.7.9.5


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