OSCL-LXR linux-6.0.1/​Documentation/​driver-api/​fpga/​fpga-mgr.rst	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 FPGA Manager
 ============
 
 Overview
 --------
 
 The FPGA manager core exports a set of functions for programming an FPGA with
 an image.  The API is manufacturer agnostic.  All manufacturer specifics are
 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.
 
 How to support a new FPGA device
 --------------------------------
 
 To add another FPGA manager, write a driver that implements a set of ops.  The
 probe function calls fpga_mgr_register() or fpga_mgr_register_full(), such as::
 
         static const struct fpga_manager_ops socfpga_fpga_ops = {
                 .write_init = socfpga_fpga_ops_configure_init,
                 .write = socfpga_fpga_ops_configure_write,
                 .write_complete = socfpga_fpga_ops_configure_complete,
                 .state = socfpga_fpga_ops_state,
         };
 
         static int socfpga_fpga_probe(struct platform_device *pdev)
         {
                 struct device *dev = &pdev->dev;
                 struct socfpga_fpga_priv *priv;
                 struct fpga_manager *mgr;
                 int ret;
 
                 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
                 if (!priv)
                         return -ENOMEM;
 
                 /*
                  * do ioremaps, get interrupts, etc. and save
                  * them in priv
                  */
 
                 mgr = fpga_mgr_register(dev, "Altera SOCFPGA FPGA Manager",
                                         &socfpga_fpga_ops, priv);
                 if (IS_ERR(mgr))
                         return PTR_ERR(mgr);
 
                 platform_set_drvdata(pdev, mgr);
 
                 return 0;
         }
 
         static int socfpga_fpga_remove(struct platform_device *pdev)
         {
                 struct fpga_manager *mgr = platform_get_drvdata(pdev);
 
                 fpga_mgr_unregister(mgr);
 
                 return 0;
         }
 
 Alternatively, the probe function could call one of the resource managed
 register functions, devm_fpga_mgr_register() or devm_fpga_mgr_register_full().
 When these functions are used, the parameter syntax is the same, but the call
 to fpga_mgr_unregister() should be removed. In the above example, the
 socfpga_fpga_remove() function would not be required.
 
 The ops will implement whatever device specific register writes are needed to
 do the programming sequence for this particular FPGA.  These ops return 0 for
 success or negative error codes otherwise.
 
 The programming sequence is::
  1. .parse_header (optional, may be called once or multiple times)
  2. .write_init
  3. .write or .write_sg (may be called once or multiple times)
  4. .write_complete
 
 The .parse_header function will set header_size and data_size to
 struct fpga_image_info. Before parse_header call, header_size is initialized
 with initial_header_size. If flag skip_header of fpga_manager_ops is true,
 .write function will get image buffer starting at header_size offset from the
 beginning. If data_size is set, .write function will get data_size bytes of
 the image buffer, otherwise .write will get data up to the end of image buffer.
 This will not affect .write_sg, .write_sg will still get whole image in
 sg_table form. If FPGA image is already mapped as a single contiguous buffer,
 whole buffer will be passed into .parse_header. If image is in scatter-gather
 form, core code will buffer up at least .initial_header_size before the first
 call of .parse_header, if it is not enough, .parse_header should set desired
 size into info->header_size and return -EAGAIN, then it will be called again
 with greater part of image buffer on the input.
 
 The .write_init function will prepare the FPGA to receive the image data. The
 buffer passed into .write_init will be at least info->header_size bytes long;
 if the whole bitstream is not immediately available then the core code will
 buffer up at least this much before starting.
 
 The .write function writes a buffer to the FPGA. The buffer may be contain the
 whole FPGA image or may be a smaller chunk of an FPGA image.  In the latter
 case, this function is called multiple times for successive chunks. This interface
 is suitable for drivers which use PIO.
 
 The .write_sg version behaves the same as .write except the input is a sg_table
 scatter list. This interface is suitable for drivers which use DMA.
 
 The .write_complete function is called after all the image has been written
 to put the FPGA into operating mode.
 
 The ops include a .state function which will determine the state the FPGA is in
 and return a code of type enum fpga_mgr_states.  It doesn't result in a change
 in state.
 
 API for implementing a new FPGA Manager driver
 ----------------------------------------------
 
 * ``fpga_mgr_states`` -  Values for :c:expr:`fpga_manager->state`.
 * struct fpga_manager -  the FPGA manager struct
 * struct fpga_manager_ops -  Low level FPGA manager driver ops
 * struct fpga_manager_info -  Parameter structure for fpga_mgr_register_full()
 * fpga_mgr_register_full() -  Create and register an FPGA manager using the
   fpga_mgr_info structure to provide the full flexibility of options
 * fpga_mgr_register() -  Create and register an FPGA manager using standard
   arguments
 * devm_fpga_mgr_register_full() -  Resource managed version of
   fpga_mgr_register_full()
 * devm_fpga_mgr_register() -  Resource managed version of fpga_mgr_register()
 * fpga_mgr_unregister() -  Unregister an FPGA manager
 
 .. kernel-doc:: include/linux/fpga/fpga-mgr.h
    :functions: fpga_mgr_states
 
 .. kernel-doc:: include/linux/fpga/fpga-mgr.h
    :functions: fpga_manager
 
 .. kernel-doc:: include/linux/fpga/fpga-mgr.h
    :functions: fpga_manager_ops
 
 .. kernel-doc:: include/linux/fpga/fpga-mgr.h
    :functions: fpga_manager_info
 
 .. kernel-doc:: drivers/fpga/fpga-mgr.c
    :functions: fpga_mgr_register_full
 
 .. kernel-doc:: drivers/fpga/fpga-mgr.c
    :functions: fpga_mgr_register
 
 .. kernel-doc:: drivers/fpga/fpga-mgr.c
    :functions: devm_fpga_mgr_register_full
 
 .. kernel-doc:: drivers/fpga/fpga-mgr.c
    :functions: devm_fpga_mgr_register
 
 .. kernel-doc:: drivers/fpga/fpga-mgr.c
    :functions: fpga_mgr_unregister

This page was automatically generated by the 2.1.0 LXR engine. The LXR team