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(), 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 = devm_fpga_mgr_create(dev, "Altera SOCFPGA FPGA Manager", 53 &socfpga_fpga_ops, priv); 54 if (!mgr) 55 return -ENOMEM; 56 57 platform_set_drvdata(pdev, mgr); 58 59 return fpga_mgr_register(mgr); 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 71 72The ops will implement whatever device specific register writes are needed to 73do the programming sequence for this particular FPGA. These ops return 0 for 74success or negative error codes otherwise. 75 76The programming sequence is:: 77 1. .write_init 78 2. .write or .write_sg (may be called once or multiple times) 79 3. .write_complete 80 81The .write_init function will prepare the FPGA to receive the image data. The 82buffer passed into .write_init will be at most .initial_header_size bytes long; 83if the whole bitstream is not immediately available then the core code will 84buffer up at least this much before starting. 85 86The .write function writes a buffer to the FPGA. The buffer may be contain the 87whole FPGA image or may be a smaller chunk of an FPGA image. In the latter 88case, this function is called multiple times for successive chunks. This interface 89is suitable for drivers which use PIO. 90 91The .write_sg version behaves the same as .write except the input is a sg_table 92scatter list. This interface is suitable for drivers which use DMA. 93 94The .write_complete function is called after all the image has been written 95to put the FPGA into operating mode. 96 97The ops include a .state function which will determine the state the FPGA is in 98and return a code of type enum fpga_mgr_states. It doesn't result in a change 99in state. 100 101API for implementing a new FPGA Manager driver 102---------------------------------------------- 103 104* ``fpga_mgr_states`` — Values for :c:member:`fpga_manager->state`. 105* struct :c:type:`fpga_manager` — the FPGA manager struct 106* struct :c:type:`fpga_manager_ops` — Low level FPGA manager driver ops 107* :c:func:`devm_fpga_mgr_create` — Allocate and init a manager struct 108* :c:func:`fpga_mgr_register` — Register an FPGA manager 109* :c:func:`fpga_mgr_unregister` — Unregister an FPGA manager 110 111.. kernel-doc:: include/linux/fpga/fpga-mgr.h 112 :functions: fpga_mgr_states 113 114.. kernel-doc:: include/linux/fpga/fpga-mgr.h 115 :functions: fpga_manager 116 117.. kernel-doc:: include/linux/fpga/fpga-mgr.h 118 :functions: fpga_manager_ops 119 120.. kernel-doc:: drivers/fpga/fpga-mgr.c 121 :functions: devm_fpga_mgr_create 122 123.. kernel-doc:: drivers/fpga/fpga-mgr.c 124 :functions: fpga_mgr_register 125 126.. kernel-doc:: drivers/fpga/fpga-mgr.c 127 :functions: fpga_mgr_unregister 128