fpga-mgr.rst (5325B)
1FPGA Manager 2============ 3 4Overview 5-------- 6 7The FPGA manager core exports a set of functions for programming an FPGA with 8an image. The API is manufacturer agnostic. All manufacturer specifics are 9hidden away in a low level driver which registers a set of ops with the core. 10The FPGA image data itself is very manufacturer specific, but for our purposes 11it's just binary data. The FPGA manager core won't parse it. 12 13The FPGA image to be programmed can be in a scatter gather list, a single 14contiguous buffer, or a firmware file. Because allocating contiguous kernel 15memory for the buffer should be avoided, users are encouraged to use a scatter 16gather list instead if possible. 17 18The particulars for programming the image are presented in a structure (struct 19fpga_image_info). This struct contains parameters such as pointers to the 20FPGA image as well as image-specific particulars such as whether the image was 21built for full or partial reconfiguration. 22 23How to support a new FPGA device 24-------------------------------- 25 26To add another FPGA manager, write a driver that implements a set of ops. The 27probe function calls fpga_mgr_register() or fpga_mgr_register_full(), such as:: 28 29 static const struct fpga_manager_ops socfpga_fpga_ops = { 30 .write_init = socfpga_fpga_ops_configure_init, 31 .write = socfpga_fpga_ops_configure_write, 32 .write_complete = socfpga_fpga_ops_configure_complete, 33 .state = socfpga_fpga_ops_state, 34 }; 35 36 static int socfpga_fpga_probe(struct platform_device *pdev) 37 { 38 struct device *dev = &pdev->dev; 39 struct socfpga_fpga_priv *priv; 40 struct fpga_manager *mgr; 41 int ret; 42 43 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 44 if (!priv) 45 return -ENOMEM; 46 47 /* 48 * do ioremaps, get interrupts, etc. and save 49 * them in priv 50 */ 51 52 mgr = fpga_mgr_register(dev, "Altera SOCFPGA FPGA Manager", 53 &socfpga_fpga_ops, priv); 54 if (IS_ERR(mgr)) 55 return PTR_ERR(mgr); 56 57 platform_set_drvdata(pdev, mgr); 58 59 return 0; 60 } 61 62 static int socfpga_fpga_remove(struct platform_device *pdev) 63 { 64 struct fpga_manager *mgr = platform_get_drvdata(pdev); 65 66 fpga_mgr_unregister(mgr); 67 68 return 0; 69 } 70 71Alternatively, the probe function could call one of the resource managed 72register functions, devm_fpga_mgr_register() or devm_fpga_mgr_register_full(). 73When these functions are used, the parameter syntax is the same, but the call 74to fpga_mgr_unregister() should be removed. In the above example, the 75socfpga_fpga_remove() function would not be required. 76 77The ops will implement whatever device specific register writes are needed to 78do the programming sequence for this particular FPGA. These ops return 0 for 79success or negative error codes otherwise. 80 81The programming sequence is:: 82 1. .write_init 83 2. .write or .write_sg (may be called once or multiple times) 84 3. .write_complete 85 86The .write_init function will prepare the FPGA to receive the image data. The 87buffer passed into .write_init will be at most .initial_header_size bytes long; 88if the whole bitstream is not immediately available then the core code will 89buffer up at least this much before starting. 90 91The .write function writes a buffer to the FPGA. The buffer may be contain the 92whole FPGA image or may be a smaller chunk of an FPGA image. In the latter 93case, this function is called multiple times for successive chunks. This interface 94is suitable for drivers which use PIO. 95 96The .write_sg version behaves the same as .write except the input is a sg_table 97scatter list. This interface is suitable for drivers which use DMA. 98 99The .write_complete function is called after all the image has been written 100to put the FPGA into operating mode. 101 102The ops include a .state function which will determine the state the FPGA is in 103and return a code of type enum fpga_mgr_states. It doesn't result in a change 104in state. 105 106API for implementing a new FPGA Manager driver 107---------------------------------------------- 108 109* ``fpga_mgr_states`` - Values for :c:expr:`fpga_manager->state`. 110* struct fpga_manager - the FPGA manager struct 111* struct fpga_manager_ops - Low level FPGA manager driver ops 112* struct fpga_manager_info - Parameter structure for fpga_mgr_register_full() 113* fpga_mgr_register_full() - Create and register an FPGA manager using the 114 fpga_mgr_info structure to provide the full flexibility of options 115* fpga_mgr_register() - Create and register an FPGA manager using standard 116 arguments 117* devm_fpga_mgr_register_full() - Resource managed version of 118 fpga_mgr_register_full() 119* devm_fpga_mgr_register() - Resource managed version of fpga_mgr_register() 120* fpga_mgr_unregister() - Unregister an FPGA manager 121 122.. kernel-doc:: include/linux/fpga/fpga-mgr.h 123 :functions: fpga_mgr_states 124 125.. kernel-doc:: include/linux/fpga/fpga-mgr.h 126 :functions: fpga_manager 127 128.. kernel-doc:: include/linux/fpga/fpga-mgr.h 129 :functions: fpga_manager_ops 130 131.. kernel-doc:: include/linux/fpga/fpga-mgr.h 132 :functions: fpga_manager_info 133 134.. kernel-doc:: drivers/fpga/fpga-mgr.c 135 :functions: fpga_mgr_register_full 136 137.. kernel-doc:: drivers/fpga/fpga-mgr.c 138 :functions: fpga_mgr_register 139 140.. kernel-doc:: drivers/fpga/fpga-mgr.c 141 :functions: devm_fpga_mgr_register_full 142 143.. kernel-doc:: drivers/fpga/fpga-mgr.c 144 :functions: devm_fpga_mgr_register 145 146.. kernel-doc:: drivers/fpga/fpga-mgr.c 147 :functions: fpga_mgr_unregister