diff options
Diffstat (limited to 'Documentation/driver-api/fpga/fpga-mgr.rst')
| -rw-r--r-- | Documentation/driver-api/fpga/fpga-mgr.rst | 81 |
1 files changed, 61 insertions, 20 deletions
diff --git a/Documentation/driver-api/fpga/fpga-mgr.rst b/Documentation/driver-api/fpga/fpga-mgr.rst index 576f1945eacd..8d2b79f696c1 100644 --- a/Documentation/driver-api/fpga/fpga-mgr.rst +++ b/Documentation/driver-api/fpga/fpga-mgr.rst @@ -24,7 +24,8 @@ 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(), such as:: +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, @@ -49,14 +50,14 @@ probe function calls fpga_mgr_register(), such as:: * them in priv */ - mgr = devm_fpga_mgr_create(dev, "Altera SOCFPGA FPGA Manager", - &socfpga_fpga_ops, priv); - if (!mgr) - return -ENOMEM; + 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 fpga_mgr_register(mgr); + return 0; } static int socfpga_fpga_remove(struct platform_device *pdev) @@ -68,18 +69,39 @@ probe function calls fpga_mgr_register(), such as:: 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. .write_init - 2. .write or .write_sg (may be called once or multiple times) - 3. .write_complete - -The .write_init function will prepare the FPGA to receive the image data. The -buffer passed into .write_init will be at most .initial_header_size bytes long; + 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. @@ -101,12 +123,22 @@ in state. API for implementing a new FPGA Manager driver ---------------------------------------------- -* ``fpga_mgr_states`` — Values for :c:member:`fpga_manager->state`. -* struct :c:type:`fpga_manager` — the FPGA manager struct -* struct :c:type:`fpga_manager_ops` — Low level FPGA manager driver ops -* :c:func:`devm_fpga_mgr_create` — Allocate and init a manager struct -* :c:func:`fpga_mgr_register` — Register an FPGA manager -* :c:func:`fpga_mgr_unregister` — Unregister an FPGA manager +* ``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 + +Helper macros ``fpga_mgr_register_full()``, ``fpga_mgr_register()``, +``devm_fpga_mgr_register_full()``, and ``devm_fpga_mgr_register()`` are available +to ease the registration. .. kernel-doc:: include/linux/fpga/fpga-mgr.h :functions: fpga_mgr_states @@ -117,11 +149,20 @@ API for implementing a new FPGA Manager driver .. 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_create + :functions: __devm_fpga_mgr_register_full .. kernel-doc:: drivers/fpga/fpga-mgr.c - :functions: fpga_mgr_register + :functions: __devm_fpga_mgr_register .. kernel-doc:: drivers/fpga/fpga-mgr.c :functions: fpga_mgr_unregister |