firmware_loader: Add firmware-upload support

Extend the firmware subsystem to support a persistent sysfs interface that
userspace may use to initiate a firmware update. For example, FPGA based
PCIe cards load firmware and FPGA images from local FLASH when the card
boots. The images in FLASH may be updated with new images provided by the
user at his/her convenience.

A device driver may call firmware_upload_register() to expose persistent
"loading" and "data" sysfs files. These files are used in the same way as
the fallback sysfs "loading" and "data" files. When 0 is written to
"loading" to complete the write of firmware data, the data is transferred
to the lower-level driver using pre-registered call-back functions. The
data transfer is done in the context of a kernel worker thread.

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Tianfei zhang <tianfei.zhang@intel.com>
Tested-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Russ Weight <russell.h.weight@intel.com>
Link: https://lore.kernel.org/r/20220421212204.36052-5-russell.h.weight@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

8 files changed, 373 insertions, 12 deletions

diff --git a/drivers/base/firmware_loader/Kconfig b/drivers/base/firmware_loader/Kconfig
index d13e4383ea0c..7e663dd972a7 100644
--- a/drivers/base/firmware_loader/Kconfig
+++ b/drivers/base/firmware_loader/Kconfig
@@ -202,5 +202,19 @@ config FW_CACHE
 
 	  If unsure, say Y.
 
+config FW_UPLOAD
+	bool "Enable users to initiate firmware updates using sysfs"
+	select FW_LOADER_SYSFS
+	select FW_LOADER_PAGED_BUF
+	help
+	  Enabling this option will allow device drivers to expose a persistent
+	  sysfs interface that allows firmware updates to be initiated from
+	  userspace. For example, FPGA based PCIe cards load firmware and FPGA
+	  images from local FLASH when the card boots. The images in FLASH may
+	  be updated with new images provided by the user. Enable this device
+	  to support cards that rely on user-initiated updates for firmware files.
+
+	  If unsure, say N.
+
 endif # FW_LOADER
 endmenu
diff --git a/drivers/base/firmware_loader/Makefile b/drivers/base/firmware_loader/Makefile
index aab213f82288..60d19f9e0ddc 100644
--- a/drivers/base/firmware_loader/Makefile
+++ b/drivers/base/firmware_loader/Makefile
@@ -7,5 +7,6 @@ firmware_class-objs := main.o
 firmware_class-$(CONFIG_FW_LOADER_USER_HELPER) += fallback.o
 firmware_class-$(CONFIG_EFI_EMBEDDED_FIRMWARE) += fallback_platform.o
 firmware_class-$(CONFIG_FW_LOADER_SYSFS) += sysfs.o
+firmware_class-$(CONFIG_FW_UPLOAD) += sysfs_upload.o
 
 obj-y += builtin/
diff --git a/drivers/base/firmware_loader/firmware.h b/drivers/base/firmware_loader/firmware.h
index d5ff32a1ba2d..fe77e91c38a2 100644
--- a/drivers/base/firmware_loader/firmware.h
+++ b/drivers/base/firmware_loader/firmware.h
@@ -87,6 +87,7 @@ struct fw_priv {
 };
 
 extern struct mutex fw_lock;
+extern struct firmware_cache fw_cache;
 
 static inline bool __fw_state_check(struct fw_priv *fw_priv,
 				    enum fw_status status)
@@ -159,7 +160,12 @@ static inline bool fw_state_is_loading(struct fw_priv *fw_priv)
 	return __fw_state_check(fw_priv, FW_STATUS_LOADING);
 }
 
+int alloc_lookup_fw_priv(const char *fw_name, struct firmware_cache *fwc,
+			 struct fw_priv **fw_priv, void *dbuf, size_t size,
+			 size_t offset, u32 opt_flags);
 int assign_fw(struct firmware *fw, struct device *device);
+void free_fw_priv(struct fw_priv *fw_priv);
+void fw_state_init(struct fw_priv *fw_priv);
 
 #ifdef CONFIG_FW_LOADER
 bool firmware_is_builtin(const struct firmware *fw);
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 6ac6c7753acc..9a8579e56c26 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -92,9 +92,9 @@ static inline struct fw_priv *to_fw_priv(struct kref *ref)
  * guarding for corner cases a global lock should be OK */
 DEFINE_MUTEX(fw_lock);
 
-static struct firmware_cache fw_cache;
+struct firmware_cache fw_cache;
 
-static void fw_state_init(struct fw_priv *fw_priv)
+void fw_state_init(struct fw_priv *fw_priv)
 {
 	struct fw_state *fw_st = &fw_priv->fw_st;
 
@@ -164,13 +164,9 @@ static struct fw_priv *__lookup_fw_priv(const char *fw_name)
 }
 
 /* Returns 1 for batching firmware requests with the same 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,
-				size_t offset,
-				u32 opt_flags)
+int alloc_lookup_fw_priv(const char *fw_name, struct firmware_cache *fwc,
+			 struct fw_priv **fw_priv, void *dbuf, size_t size,
+			 size_t offset, u32 opt_flags)
 {
 	struct fw_priv *tmp;
 
@@ -225,7 +221,7 @@ static void __free_fw_priv(struct kref *ref)
 	kfree(fw_priv);
 }
 
-static void free_fw_priv(struct fw_priv *fw_priv)
+void free_fw_priv(struct fw_priv *fw_priv)
 {
 	struct firmware_cache *fwc = fw_priv->fwc;
 	spin_lock(&fwc->lock);
diff --git a/drivers/base/firmware_loader/sysfs.c b/drivers/base/firmware_loader/sysfs.c
index 1509cb6b6e60..4a956cc3b7ea 100644
--- a/drivers/base/firmware_loader/sysfs.c
+++ b/drivers/base/firmware_loader/sysfs.c
@@ -6,8 +6,8 @@
 #include <linux/slab.h>
 #include <linux/types.h>
 
-#include "firmware.h"
 #include "sysfs.h"
+#include "sysfs_upload.h"
 
 /*
  * sysfs support for firmware loader
@@ -94,6 +94,10 @@ static void fw_dev_release(struct device *dev)
 {
 	struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
 
+	if (fw_sysfs->fw_upload_priv) {
+		free_fw_priv(fw_sysfs->fw_priv);
+		kfree(fw_sysfs->fw_upload_priv);
+	}
 	kfree(fw_sysfs);
 }
 
@@ -199,6 +203,14 @@ static ssize_t firmware_loading_store(struct device *dev,
 				written = rc;
 			} else {
 				fw_state_done(fw_priv);
+
+				/*
+				 * If this is a user-initiated firmware upload
+				 * then start the upload in a worker thread now.
+				 */
+				rc = fw_upload_start(fw_sysfs);
+				if (rc)
+					written = rc;
 			}
 			break;
 		}
@@ -208,6 +220,9 @@ static ssize_t firmware_loading_store(struct device *dev,
 		fallthrough;
 	case -1:
 		fw_load_abort(fw_sysfs);
+		if (fw_sysfs->fw_upload_priv)
+			fw_state_init(fw_sysfs->fw_priv);
+
 		break;
 	}
 out:
@@ -215,7 +230,7 @@ out:
 	return written;
 }
 
-static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
+DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 
 static void firmware_rw_data(struct fw_priv *fw_priv, char *buffer,
 			     loff_t offset, size_t count, bool read)
diff --git a/drivers/base/firmware_loader/sysfs.h b/drivers/base/firmware_loader/sysfs.h
index b7b5c1766052..c21bcfe374ff 100644
--- a/drivers/base/firmware_loader/sysfs.h
+++ b/drivers/base/firmware_loader/sysfs.h
@@ -4,9 +4,12 @@
 
 #include <linux/device.h>
 
+#include "firmware.h"
+
 MODULE_IMPORT_NS(FIRMWARE_LOADER_PRIVATE);
 
 extern struct firmware_fallback_config fw_fallback_config;
+extern struct device_attribute dev_attr_loading;
 
 #ifdef CONFIG_FW_LOADER_USER_HELPER
 /**
@@ -73,6 +76,7 @@ struct fw_sysfs {
 	struct device dev;
 	struct fw_priv *fw_priv;
 	struct firmware *fw;
+	void *fw_upload_priv;
 };
 
 static inline struct fw_sysfs *to_fw_sysfs(struct device *dev)
diff --git a/drivers/base/firmware_loader/sysfs_upload.c b/drivers/base/firmware_loader/sysfs_upload.c
new file mode 100644
index 000000000000..0a6450d1974f
--- /dev/null
+++ b/drivers/base/firmware_loader/sysfs_upload.c
@@ -0,0 +1,276 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/firmware.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "sysfs.h"
+#include "sysfs_upload.h"
+
+/*
+ * Support for user-space to initiate a firmware upload to a device.
+ */
+
+static void fw_upload_update_progress(struct fw_upload_priv *fwlp,
+				      enum fw_upload_prog new_progress)
+{
+	mutex_lock(&fwlp->lock);
+	fwlp->progress = new_progress;
+	mutex_unlock(&fwlp->lock);
+}
+
+static void fw_upload_set_error(struct fw_upload_priv *fwlp,
+				enum fw_upload_err err_code)
+{
+	mutex_lock(&fwlp->lock);
+	fwlp->err_progress = fwlp->progress;
+	fwlp->err_code = err_code;
+	mutex_unlock(&fwlp->lock);
+}
+
+static void fw_upload_prog_complete(struct fw_upload_priv *fwlp)
+{
+	mutex_lock(&fwlp->lock);
+	fwlp->progress = FW_UPLOAD_PROG_IDLE;
+	mutex_unlock(&fwlp->lock);
+}
+
+static void fw_upload_main(struct work_struct *work)
+{
+	struct fw_upload_priv *fwlp;
+	struct fw_sysfs *fw_sysfs;
+	u32 written = 0, offset = 0;
+	enum fw_upload_err ret;
+	struct device *fw_dev;
+	struct fw_upload *fwl;
+
+	fwlp = container_of(work, struct fw_upload_priv, work);
+	fwl = fwlp->fw_upload;
+	fw_sysfs = (struct fw_sysfs *)fwl->priv;
+	fw_dev = &fw_sysfs->dev;
+
+	fw_upload_update_progress(fwlp, FW_UPLOAD_PROG_PREPARING);
+	ret = fwlp->ops->prepare(fwl, fwlp->data, fwlp->remaining_size);
+	if (ret != FW_UPLOAD_ERR_NONE) {
+		fw_upload_set_error(fwlp, ret);
+		goto putdev_exit;
+	}
+
+	fw_upload_update_progress(fwlp, FW_UPLOAD_PROG_TRANSFERRING);
+	while (fwlp->remaining_size) {
+		ret = fwlp->ops->write(fwl, fwlp->data, offset,
+					fwlp->remaining_size, &written);
+		if (ret != FW_UPLOAD_ERR_NONE || !written) {
+			if (ret == FW_UPLOAD_ERR_NONE) {
+				dev_warn(fw_dev, "write-op wrote zero data\n");
+				ret = FW_UPLOAD_ERR_RW_ERROR;
+			}
+			fw_upload_set_error(fwlp, ret);
+			goto done;
+		}
+
+		fwlp->remaining_size -= written;
+		offset += written;
+	}
+
+	fw_upload_update_progress(fwlp, FW_UPLOAD_PROG_PROGRAMMING);
+	ret = fwlp->ops->poll_complete(fwl);
+	if (ret != FW_UPLOAD_ERR_NONE)
+		fw_upload_set_error(fwlp, ret);
+
+done:
+	if (fwlp->ops->cleanup)
+		fwlp->ops->cleanup(fwl);
+
+putdev_exit:
+	put_device(fw_dev->parent);
+
+	/*
+	 * Note: fwlp->remaining_size is left unmodified here to provide
+	 * additional information on errors. It will be reinitialized when
+	 * the next firmeware upload begins.
+	 */
+	mutex_lock(&fw_lock);
+	fw_free_paged_buf(fw_sysfs->fw_priv);
+	fw_state_init(fw_sysfs->fw_priv);
+	mutex_unlock(&fw_lock);
+	fwlp->data = NULL;
+	fw_upload_prog_complete(fwlp);
+}
+
+/*
+ * Start a worker thread to upload data to the parent driver.
+ * Must be called with fw_lock held.
+ */
+int fw_upload_start(struct fw_sysfs *fw_sysfs)
+{
+	struct fw_priv *fw_priv = fw_sysfs->fw_priv;
+	struct device *fw_dev = &fw_sysfs->dev;
+	struct fw_upload_priv *fwlp;
+
+	if (!fw_sysfs->fw_upload_priv)
+		return 0;
+
+	if (!fw_priv->size) {
+		fw_free_paged_buf(fw_priv);
+		fw_state_init(fw_sysfs->fw_priv);
+		return 0;
+	}
+
+	fwlp = fw_sysfs->fw_upload_priv;
+	mutex_lock(&fwlp->lock);
+
+	/* Do not interfere with an on-going fw_upload */
+	if (fwlp->progress != FW_UPLOAD_PROG_IDLE) {
+		mutex_unlock(&fwlp->lock);
+		return -EBUSY;
+	}
+
+	get_device(fw_dev->parent); /* released in fw_upload_main */
+
+	fwlp->progress = FW_UPLOAD_PROG_RECEIVING;
+	fwlp->err_code = 0;
+	fwlp->remaining_size = fw_priv->size;
+	fwlp->data = fw_priv->data;
+
+	pr_debug("%s: fw-%s fw_priv=%p data=%p size=%u\n",
+		 __func__, fw_priv->fw_name,
+		 fw_priv, fw_priv->data,
+		 (unsigned int)fw_priv->size);
+
+	queue_work(system_long_wq, &fwlp->work);
+	mutex_unlock(&fwlp->lock);
+
+	return 0;
+}
+
+/**
+ * firmware_upload_register() - register for the firmware upload sysfs API
+ * @parent: parent device instantiating firmware upload
+ * @name: firmware name to be associated with this device
+ * @ops: pointer to structure of firmware upload ops
+ * @dd_handle: pointer to parent driver private data
+ *
+ *	@name must be unique among all users of firmware upload. The firmware
+ *	sysfs files for this device will be found at /sys/class/firmware/@name.
+ *
+ *	Return: struct fw_upload pointer or ERR_PTR()
+ *
+ **/
+struct fw_upload *
+firmware_upload_register(struct module *module, struct device *parent,
+			 const char *name, const struct fw_upload_ops *ops,
+			 void *dd_handle)
+{
+	u32 opt_flags = FW_OPT_NOCACHE;
+	struct fw_upload *fw_upload;
+	struct fw_upload_priv *fw_upload_priv;
+	struct fw_sysfs *fw_sysfs;
+	struct fw_priv *fw_priv;
+	struct device *fw_dev;
+	int ret;
+
+	if (!name || name[0] == '\0')
+		return ERR_PTR(-EINVAL);
+
+	if (!ops || !ops->cancel || !ops->prepare ||
+	    !ops->write || !ops->poll_complete) {
+		dev_err(parent, "Attempt to register without all required ops\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (!try_module_get(module))
+		return ERR_PTR(-EFAULT);
+
+	fw_upload = kzalloc(sizeof(*fw_upload), GFP_KERNEL);
+	if (!fw_upload) {
+		ret = -ENOMEM;
+		goto exit_module_put;
+	}
+
+	fw_upload_priv = kzalloc(sizeof(*fw_upload_priv), GFP_KERNEL);
+	if (!fw_upload_priv) {
+		ret = -ENOMEM;
+		goto free_fw_upload;
+	}
+
+	fw_upload_priv->fw_upload = fw_upload;
+	fw_upload_priv->ops = ops;
+	mutex_init(&fw_upload_priv->lock);
+	fw_upload_priv->module = module;
+	fw_upload_priv->name = name;
+	fw_upload_priv->err_code = 0;
+	fw_upload_priv->progress = FW_UPLOAD_PROG_IDLE;
+	INIT_WORK(&fw_upload_priv->work, fw_upload_main);
+	fw_upload->dd_handle = dd_handle;
+
+	fw_sysfs = fw_create_instance(NULL, name, parent, opt_flags);
+	if (IS_ERR(fw_sysfs)) {
+		ret = PTR_ERR(fw_sysfs);
+		goto free_fw_upload_priv;
+	}
+	fw_upload->priv = fw_sysfs;
+	fw_sysfs->fw_upload_priv = fw_upload_priv;
+	fw_dev = &fw_sysfs->dev;
+
+	ret = alloc_lookup_fw_priv(name, &fw_cache, &fw_priv,  NULL, 0, 0,
+				   FW_OPT_NOCACHE);
+	if (ret != 0) {
+		if (ret > 0)
+			ret = -EINVAL;
+		goto free_fw_sysfs;
+	}
+	fw_priv->is_paged_buf = true;
+	fw_sysfs->fw_priv = fw_priv;
+
+	ret = device_add(fw_dev);
+	if (ret) {
+		dev_err(fw_dev, "%s: device_register failed\n", __func__);
+		put_device(fw_dev);
+		goto exit_module_put;
+	}
+
+	return fw_upload;
+
+free_fw_sysfs:
+	kfree(fw_sysfs);
+
+free_fw_upload_priv:
+	kfree(fw_upload_priv);
+
+free_fw_upload:
+	kfree(fw_upload);
+
+exit_module_put:
+	module_put(module);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(firmware_upload_register);
+
+/**
+ * firmware_upload_unregister() - Unregister firmware upload interface
+ * @fw_upload: pointer to struct fw_upload
+ **/
+void firmware_upload_unregister(struct fw_upload *fw_upload)
+{
+	struct fw_sysfs *fw_sysfs = fw_upload->priv;
+	struct fw_upload_priv *fw_upload_priv = fw_sysfs->fw_upload_priv;
+
+	mutex_lock(&fw_upload_priv->lock);
+	if (fw_upload_priv->progress == FW_UPLOAD_PROG_IDLE) {
+		mutex_unlock(&fw_upload_priv->lock);
+		goto unregister;
+	}
+
+	fw_upload_priv->ops->cancel(fw_upload);
+	mutex_unlock(&fw_upload_priv->lock);
+
+	/* Ensure lower-level device-driver is finished */
+	flush_work(&fw_upload_priv->work);
+
+unregister:
+	device_unregister(&fw_sysfs->dev);
+	module_put(fw_upload_priv->module);
+}
+EXPORT_SYMBOL_GPL(firmware_upload_unregister);
diff --git a/drivers/base/firmware_loader/sysfs_upload.h b/drivers/base/firmware_loader/sysfs_upload.h
new file mode 100644
index 000000000000..18bd4d99f064
--- /dev/null
+++ b/drivers/base/firmware_loader/sysfs_upload.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __FIRMWARE_UPLOAD_H
+#define __FIRMWARE_UPLOAD_H
+
+#include <linux/device.h>
+
+/**
+ * enum fw_upload_prog - firmware upload progress codes
+ * @FW_UPLOAD_PROG_IDLE: there is no firmware upload in progress
+ * @FW_UPLOAD_PROG_RECEIVING: worker thread is receiving firmware data
+ * @FW_UPLOAD_PROG_PREPARING: target device is preparing for firmware upload
+ * @FW_UPLOAD_PROG_TRANSFERRING: data is being copied to the device
+ * @FW_UPLOAD_PROG_PROGRAMMING: device is performing the firmware update
+ * @FW_UPLOAD_PROG_MAX: Maximum progress code marker
+ */
+enum fw_upload_prog {
+	FW_UPLOAD_PROG_IDLE,
+	FW_UPLOAD_PROG_RECEIVING,
+	FW_UPLOAD_PROG_PREPARING,
+	FW_UPLOAD_PROG_TRANSFERRING,
+	FW_UPLOAD_PROG_PROGRAMMING,
+	FW_UPLOAD_PROG_MAX
+};
+
+struct fw_upload_priv {
+	struct fw_upload *fw_upload;
+	struct module *module;
+	const char *name;
+	const struct fw_upload_ops *ops;
+	struct mutex lock;		  /* protect data structure contents */
+	struct work_struct work;
+	const u8 *data;			  /* pointer to update data */
+	u32 remaining_size;		  /* size remaining to transfer */
+	enum fw_upload_prog progress;
+	enum fw_upload_prog err_progress; /* progress at time of failure */
+	enum fw_upload_err err_code;	  /* security manager error code */
+};
+
+#ifdef CONFIG_FW_UPLOAD
+int fw_upload_start(struct fw_sysfs *fw_sysfs);
+umode_t fw_upload_is_visible(struct kobject *kobj, struct attribute *attr, int n);
+#else
+static inline int fw_upload_start(struct fw_sysfs *fw_sysfs)
+{
+	return 0;
+}
+#endif
+
+#endif /* __FIRMWARE_UPLOAD_H */