1 files changed, 66 insertions, 66 deletions

diff --git a/Documentation/fpga/fpga-mgr.txt b/Documentation/fpga/fpga-mgr.txt
index 78f197fadfd1..cc6413ed6fc9 100644
--- a/Documentation/fpga/fpga-mgr.txt
+++ b/Documentation/fpga/fpga-mgr.txt
@@ -11,61 +11,65 @@ hidden away in a low level driver which registers a set of ops with the core.
 The FPGA image data itself is very manufacturer specific, but for our purposes
 it's just binary data.  The FPGA manager core won't parse it.
 
+The FPGA image to be programmed can be in a scatter gather list, a single
+contiguous buffer, or a firmware file.  Because allocating contiguous kernel
+memory for the buffer should be avoided, users are encouraged to use a scatter
+gather list instead if possible.
+
+The particulars for programming the image are presented in a structure (struct
+fpga_image_info).  This struct contains parameters such as pointers to the
+FPGA image as well as image-specific particulars such as whether the image was
+built for full or partial reconfiguration.
 
 API Functions:
 ==============
 
-To program the FPGA from a file or from a buffer:
--------------------------------------------------
-
-        int fpga_mgr_buf_load(struct fpga_manager *mgr,
-                              struct fpga_image_info *info,
-                              const char *buf, size_t count);
-
-Load the FPGA from an image which exists as a contiguous buffer in
-memory. Allocating contiguous kernel memory for the buffer should be avoided,
-users are encouraged to use the _sg interface instead of this.
-
-        int fpga_mgr_buf_load_sg(struct fpga_manager *mgr,
-                                 struct fpga_image_info *info,
-                                 struct sg_table *sgt);
+To program the FPGA:
+--------------------
 
-Load the FPGA from an image from non-contiguous in memory. Callers can
-construct a sg_table using alloc_page backed memory.
+        int fpga_mgr_load(struct fpga_manager *mgr,
+                          struct fpga_image_info *info);
 
-        int fpga_mgr_firmware_load(struct fpga_manager *mgr,
-                                   struct fpga_image_info *info,
-                                   const char *image_name);
-
-Load the FPGA from an image which exists as a file.  The image file must be on
-the firmware search path (see the firmware class documentation).  If successful,
+Load the FPGA from an image which is indicated in the info.  If successful,
 the FPGA ends up in operating mode.  Return 0 on success or a negative error
 code.
 
-A FPGA design contained in a FPGA image file will likely have particulars that
-affect how the image is programmed to the FPGA.  These are contained in struct
-fpga_image_info.  Currently the only such particular is a single flag bit
-indicating whether the image is for full or partial reconfiguration.
+To allocate or free a struct fpga_image_info:
+---------------------------------------------
+
+        struct fpga_image_info *fpga_image_info_alloc(struct device *dev);
+
+        void fpga_image_info_free(struct fpga_image_info *info);
 
 To get/put a reference to a FPGA manager:
 -----------------------------------------
 
         struct fpga_manager *of_fpga_mgr_get(struct device_node *node);
         struct fpga_manager *fpga_mgr_get(struct device *dev);
+        void fpga_mgr_put(struct fpga_manager *mgr);
 
-Given a DT node or device, get an exclusive reference to a FPGA manager.
+Given a DT node or device, get a reference to a FPGA manager.  This pointer
+can be saved until you are ready to program the FPGA.  fpga_mgr_put releases
+the reference.
 
-        void fpga_mgr_put(struct fpga_manager *mgr);
 
-Release the reference.
+To get exclusive control of a FPGA manager:
+-------------------------------------------
+
+        int fpga_mgr_lock(struct fpga_manager *mgr);
+        void fpga_mgr_unlock(struct fpga_manager *mgr);
+
+The user should call fpga_mgr_lock and verify that it returns 0 before
+attempting to program the FPGA.  Likewise, the user should call
+fpga_mgr_unlock when done programming the FPGA.
 
 
 To register or unregister the low level FPGA-specific driver:
 -------------------------------------------------------------
 
         int fpga_mgr_register(struct device *dev, const char *name,
-                              const struct fpga_manager_ops *mops,
-                              void *priv);
+                              const struct fpga_manager_ops *mops,
+                              void *priv);
 
         void fpga_mgr_unregister(struct device *dev);
 
@@ -75,62 +79,58 @@ device."
 
 How to write an image buffer to a supported FPGA
 ================================================
-/* Include to get the API */
 #include <linux/fpga/fpga-mgr.h>
 
-/* device node that specifies the FPGA manager to use */
-struct device_node *mgr_node = ...
+struct fpga_manager *mgr;
+struct fpga_image_info *info;
+int ret;
 
-/* FPGA image is in this buffer.  count is size of the buffer. */
-char *buf = ...
-int count = ...
+/*
+ * Get a reference to FPGA manager.  The manager is not locked, so you can
+ * hold onto this reference without it preventing programming.
+ *
+ * This example uses the device node of the manager.  Alternatively, use
+ * fpga_mgr_get(dev) instead if you have the device.
+ */
+mgr = of_fpga_mgr_get(mgr_node);
 
 /* struct with information about the FPGA image to program. */
-struct fpga_image_info info;
+info = fpga_image_info_alloc(dev);
 
 /* flags indicates whether to do full or partial reconfiguration */
-info.flags = 0;
+info->flags = FPGA_MGR_PARTIAL_RECONFIG;
 
-int ret;
+/*
+ * At this point, indicate where the image is. This is pseudo-code; you're
+ * going to use one of these three.
+ */
+if (image is in a scatter gather table) {
 
-/* Get exclusive control of FPGA manager */
-struct fpga_manager *mgr = of_fpga_mgr_get(mgr_node);
+        info->sgt = [your scatter gather table]
 
-/* Load the buffer to the FPGA */
-ret = fpga_mgr_buf_load(mgr, &info, buf, count);
-
-/* Release the FPGA manager */
-fpga_mgr_put(mgr);
-
-
-How to write an image file to a supported FPGA
-==============================================
-/* Include to get the API */
-#include <linux/fpga/fpga-mgr.h>
+} else if (image is in a buffer) {
 
-/* device node that specifies the FPGA manager to use */
-struct device_node *mgr_node = ...
+        info->buf = [your image buffer]
+        info->count = [image buffer size]
 
-/* FPGA image is in this file which is in the firmware search path */
-const char *path = "fpga-image-9.rbf"
+} else if (image is in a firmware file) {
 
-/* struct with information about the FPGA image to program. */
-struct fpga_image_info info;
-
-/* flags indicates whether to do full or partial reconfiguration */
-info.flags = 0;
+        info->firmware_name = devm_kstrdup(dev, firmware_name, GFP_KERNEL);
 
-int ret;
+}
 
 /* Get exclusive control of FPGA manager */
-struct fpga_manager *mgr = of_fpga_mgr_get(mgr_node);
+ret = fpga_mgr_lock(mgr);
 
-/* Get the firmware image (path) and load it to the FPGA */
-ret = fpga_mgr_firmware_load(mgr, &info, path);
+/* Load the buffer to the FPGA */
+ret = fpga_mgr_buf_load(mgr, &info, buf, count);
 
 /* Release the FPGA manager */
+fpga_mgr_unlock(mgr);
 fpga_mgr_put(mgr);
 
+/* Deallocate the image info if you're done with it */
+fpga_image_info_free(info);
 
 How to support a new FPGA device
 ================================