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. .parse_header (optional, may be called once or multiple times) 83 2. .write_init 84 3. .write or .write_sg (may be called once or multiple times) 85 4. .write_complete 86 87The .parse_header function will set header_size and data_size to 88struct fpga_image_info. Before parse_header call, header_size is initialized 89with initial_header_size. If flag skip_header of fpga_manager_ops is true, 90.write function will get image buffer starting at header_size offset from the 91beginning. If data_size is set, .write function will get data_size bytes of 92the image buffer, otherwise .write will get data up to the end of image buffer. 93This will not affect .write_sg, .write_sg will still get whole image in 94sg_table form. If FPGA image is already mapped as a single contiguous buffer, 95whole buffer will be passed into .parse_header. If image is in scatter-gather 96form, core code will buffer up at least .initial_header_size before the first 97call of .parse_header, if it is not enough, .parse_header should set desired 98size into info->header_size and return -EAGAIN, then it will be called again 99with greater part of image buffer on the input. 100 101The .write_init function will prepare the FPGA to receive the image data. The 102buffer passed into .write_init will be at least info->header_size bytes long; 103if the whole bitstream is not immediately available then the core code will 104buffer up at least this much before starting. 105 106The .write function writes a buffer to the FPGA. The buffer may be contain the 107whole FPGA image or may be a smaller chunk of an FPGA image. In the latter 108case, this function is called multiple times for successive chunks. This interface 109is suitable for drivers which use PIO. 110 111The .write_sg version behaves the same as .write except the input is a sg_table 112scatter list. This interface is suitable for drivers which use DMA. 113 114The .write_complete function is called after all the image has been written 115to put the FPGA into operating mode. 116 117The ops include a .state function which will determine the state the FPGA is in 118and return a code of type enum fpga_mgr_states. It doesn't result in a change 119in state. 120 121API for implementing a new FPGA Manager driver 122---------------------------------------------- 123 124* ``fpga_mgr_states`` - Values for :c:expr:`fpga_manager->state`. 125* struct fpga_manager - the FPGA manager struct 126* struct fpga_manager_ops - Low level FPGA manager driver ops 127* struct fpga_manager_info - Parameter structure for fpga_mgr_register_full() 128* fpga_mgr_register_full() - Create and register an FPGA manager using the 129 fpga_mgr_info structure to provide the full flexibility of options 130* fpga_mgr_register() - Create and register an FPGA manager using standard 131 arguments 132* devm_fpga_mgr_register_full() - Resource managed version of 133 fpga_mgr_register_full() 134* devm_fpga_mgr_register() - Resource managed version of fpga_mgr_register() 135* fpga_mgr_unregister() - Unregister an FPGA manager 136 137.. kernel-doc:: include/linux/fpga/fpga-mgr.h 138 :functions: fpga_mgr_states 139 140.. kernel-doc:: include/linux/fpga/fpga-mgr.h 141 :functions: fpga_manager 142 143.. kernel-doc:: include/linux/fpga/fpga-mgr.h 144 :functions: fpga_manager_ops 145 146.. kernel-doc:: include/linux/fpga/fpga-mgr.h 147 :functions: fpga_manager_info 148 149.. kernel-doc:: drivers/fpga/fpga-mgr.c 150 :functions: fpga_mgr_register_full 151 152.. kernel-doc:: drivers/fpga/fpga-mgr.c 153 :functions: fpga_mgr_register 154 155.. kernel-doc:: drivers/fpga/fpga-mgr.c 156 :functions: devm_fpga_mgr_register_full 157 158.. kernel-doc:: drivers/fpga/fpga-mgr.c 159 :functions: devm_fpga_mgr_register 160 161.. kernel-doc:: drivers/fpga/fpga-mgr.c 162 :functions: fpga_mgr_unregister 163