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authorHans de Goede <hdegoede@redhat.com>2020-01-15 17:35:48 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-03-20 14:54:04 +0100
commite4c2c0ff00ecaf8e245455a199b86ce22143becf (patch)
treefa9b9bc1bd67f40fb2dd9966f6d86fcefb58148e /drivers/base
parent4445eb6d942a4ba0e6ac07ca555dec83577289e8 (diff)
downloadlinux-e4c2c0ff00ecaf8e245455a199b86ce22143becf.tar.bz2
firmware: Add new platform fallback mechanism and firmware_request_platform()
In some cases the platform's main firmware (e.g. the UEFI fw) may contain an embedded copy of device firmware which needs to be (re)loaded into the peripheral. Normally such firmware would be part of linux-firmware, but in some cases this is not feasible, for 2 reasons: 1) The firmware is customized for a specific use-case of the chipset / use with a specific hardware model, so we cannot have a single firmware file for the chipset. E.g. touchscreen controller firmwares are compiled specifically for the hardware model they are used with, as they are calibrated for a specific model digitizer. 2) Despite repeated attempts we have failed to get permission to redistribute the firmware. This is especially a problem with customized firmwares, these get created by the chip vendor for a specific ODM and the copyright may partially belong with the ODM, so the chip vendor cannot give a blanket permission to distribute these. This commit adds a new platform fallback mechanism to the firmware loader which will try to lookup a device fw copy embedded in the platform's main firmware if direct filesystem lookup fails. Drivers which need such embedded fw copies can enable this fallback mechanism by using the new firmware_request_platform() function. Note that for now this is only supported on EFI platforms and even on these platforms firmware_fallback_platform() only works if CONFIG_EFI_EMBEDDED_FIRMWARE is enabled (this gets selected by drivers which need this), in all other cases firmware_fallback_platform() simply always returns -ENOENT. Reported-by: Dave Olsthoorn <dave@bewaar.me> Suggested-by: Peter Jones <pjones@redhat.com> Acked-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Link: https://lore.kernel.org/r/20200115163554.101315-5-hdegoede@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/firmware_loader/Makefile1
-rw-r--r--drivers/base/firmware_loader/fallback.h10
-rw-r--r--drivers/base/firmware_loader/fallback_platform.c36
-rw-r--r--drivers/base/firmware_loader/firmware.h4
-rw-r--r--drivers/base/firmware_loader/main.c27
5 files changed, 78 insertions, 0 deletions
diff --git a/drivers/base/firmware_loader/Makefile b/drivers/base/firmware_loader/Makefile
index 0b2dfa6259c9..e87843408fe6 100644
--- a/drivers/base/firmware_loader/Makefile
+++ b/drivers/base/firmware_loader/Makefile
@@ -5,5 +5,6 @@ obj-$(CONFIG_FW_LOADER_USER_HELPER) += fallback_table.o
obj-$(CONFIG_FW_LOADER) += firmware_class.o
firmware_class-objs := main.o
firmware_class-$(CONFIG_FW_LOADER_USER_HELPER) += fallback.o
+firmware_class-$(CONFIG_EFI_EMBEDDED_FIRMWARE) += fallback_platform.o
obj-y += builtin/
diff --git a/drivers/base/firmware_loader/fallback.h b/drivers/base/firmware_loader/fallback.h
index 21063503e4ea..06f4577733a8 100644
--- a/drivers/base/firmware_loader/fallback.h
+++ b/drivers/base/firmware_loader/fallback.h
@@ -66,4 +66,14 @@ static inline void unregister_sysfs_loader(void)
}
#endif /* CONFIG_FW_LOADER_USER_HELPER */
+#ifdef CONFIG_EFI_EMBEDDED_FIRMWARE
+int firmware_fallback_platform(struct fw_priv *fw_priv, enum fw_opt opt_flags);
+#else
+static inline int firmware_fallback_platform(struct fw_priv *fw_priv,
+ enum fw_opt opt_flags)
+{
+ return -ENOENT;
+}
+#endif
+
#endif /* __FIRMWARE_FALLBACK_H */
diff --git a/drivers/base/firmware_loader/fallback_platform.c b/drivers/base/firmware_loader/fallback_platform.c
new file mode 100644
index 000000000000..c88c745590fe
--- /dev/null
+++ b/drivers/base/firmware_loader/fallback_platform.c
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/efi_embedded_fw.h>
+#include <linux/property.h>
+#include <linux/security.h>
+#include <linux/vmalloc.h>
+
+#include "fallback.h"
+#include "firmware.h"
+
+int firmware_fallback_platform(struct fw_priv *fw_priv, enum fw_opt opt_flags)
+{
+ const u8 *data;
+ size_t size;
+ int rc;
+
+ if (!(opt_flags & FW_OPT_FALLBACK_PLATFORM))
+ return -ENOENT;
+
+ rc = security_kernel_load_data(LOADING_FIRMWARE_EFI_EMBEDDED);
+ if (rc)
+ return rc;
+
+ rc = efi_get_embedded_fw(fw_priv->fw_name, &data, &size);
+ if (rc)
+ return rc; /* rc == -ENOENT when the fw was not found */
+
+ fw_priv->data = vmalloc(size);
+ if (!fw_priv->data)
+ return -ENOMEM;
+
+ memcpy(fw_priv->data, data, size);
+ fw_priv->size = size;
+ fw_state_done(fw_priv);
+ return 0;
+}
diff --git a/drivers/base/firmware_loader/firmware.h b/drivers/base/firmware_loader/firmware.h
index 8656e5239a80..25836a6afc9f 100644
--- a/drivers/base/firmware_loader/firmware.h
+++ b/drivers/base/firmware_loader/firmware.h
@@ -29,6 +29,9 @@
* firmware caching mechanism.
* @FW_OPT_NOFALLBACK_SYSFS: Disable the sysfs fallback mechanism. Takes
* precedence over &FW_OPT_UEVENT and &FW_OPT_USERHELPER.
+ * @FW_OPT_FALLBACK_PLATFORM: Enable fallback to device fw copy embedded in
+ * the platform's main firmware. If both this fallback and the sysfs
+ * fallback are enabled, then this fallback will be tried first.
*/
enum fw_opt {
FW_OPT_UEVENT = BIT(0),
@@ -37,6 +40,7 @@ enum fw_opt {
FW_OPT_NO_WARN = BIT(3),
FW_OPT_NOCACHE = BIT(4),
FW_OPT_NOFALLBACK_SYSFS = BIT(5),
+ FW_OPT_FALLBACK_PLATFORM = BIT(6),
};
enum fw_status {
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 59d1dc322080..76f79913916d 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -778,6 +778,9 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
fw_decompress_xz);
#endif
+ if (ret == -ENOENT)
+ ret = firmware_fallback_platform(fw->priv, opt_flags);
+
if (ret) {
if (!(opt_flags & FW_OPT_NO_WARN))
dev_warn(device,
@@ -886,6 +889,30 @@ int request_firmware_direct(const struct firmware **firmware_p,
EXPORT_SYMBOL_GPL(request_firmware_direct);
/**
+ * firmware_request_platform() - request firmware with platform-fw fallback
+ * @firmware: pointer to firmware image
+ * @name: name of firmware file
+ * @device: device for which firmware is being loaded
+ *
+ * This function is similar in behaviour to request_firmware, except that if
+ * direct filesystem lookup fails, it will fallback to looking for a copy of the
+ * requested firmware embedded in the platform's main (e.g. UEFI) firmware.
+ **/
+int firmware_request_platform(const struct firmware **firmware,
+ const char *name, struct device *device)
+{
+ int ret;
+
+ /* Need to pin this module until return */
+ __module_get(THIS_MODULE);
+ ret = _request_firmware(firmware, name, device, NULL, 0,
+ FW_OPT_UEVENT | FW_OPT_FALLBACK_PLATFORM);
+ module_put(THIS_MODULE);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(firmware_request_platform);
+
+/**
* firmware_request_cache() - cache firmware for suspend so resume can use it
* @name: name of firmware file
* @device: device for which firmware should be cached for