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| -rw-r--r-- | Documentation/driver-api/fpga/fpga-mgr.rst | 220 | ||||
| -rw-r--r-- | Documentation/driver-api/fpga/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/fpga/fpga-mgr.txt | 218 |
3 files changed, 221 insertions, 218 deletions
diff --git a/Documentation/driver-api/fpga/fpga-mgr.rst b/Documentation/driver-api/fpga/fpga-mgr.rst new file mode 100644 index 000000000000..bcf2dd24e179 --- /dev/null +++ b/Documentation/driver-api/fpga/fpga-mgr.rst @@ -0,0 +1,220 @@ +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(), 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_create(dev, "Altera SOCFPGA FPGA Manager", + &socfpga_fpga_ops, priv); + if (!mgr) + return -ENOMEM; + + platform_set_drvdata(pdev, mgr); + + ret = fpga_mgr_register(mgr); + if (ret) + fpga_mgr_free(mgr); + + return ret; + } + + static int socfpga_fpga_remove(struct platform_device *pdev) + { + struct fpga_manager *mgr = platform_get_drvdata(pdev); + + fpga_mgr_unregister(mgr); + + return 0; + } + + +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 atmost .initial_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 read the hardware FPGA manager and +return a code of type enum fpga_mgr_states. It doesn't result in a change in +hardware state. + +How to write an image buffer to a supported FPGA +------------------------------------------------ + +Some sample code:: + + #include <linux/fpga/fpga-mgr.h> + + struct fpga_manager *mgr; + struct fpga_image_info *info; + int ret; + + /* + * Get a reference to FPGA manager. The manager is not locked, so you can + * hold onto this reference without it preventing programming. + * + * This example uses the device node of the manager. Alternatively, use + * fpga_mgr_get(dev) instead if you have the device. + */ + mgr = of_fpga_mgr_get(mgr_node); + + /* struct with information about the FPGA image to program. */ + info = fpga_image_info_alloc(dev); + + /* flags indicates whether to do full or partial reconfiguration */ + info->flags = FPGA_MGR_PARTIAL_RECONFIG; + + /* + * At this point, indicate where the image is. This is pseudo-code; you're + * going to use one of these three. + */ + if (image is in a scatter gather table) { + + info->sgt = [your scatter gather table] + + } else if (image is in a buffer) { + + info->buf = [your image buffer] + info->count = [image buffer size] + + } else if (image is in a firmware file) { + + info->firmware_name = devm_kstrdup(dev, firmware_name, GFP_KERNEL); + + } + + /* Get exclusive control of FPGA manager */ + ret = fpga_mgr_lock(mgr); + + /* Load the buffer to the FPGA */ + ret = fpga_mgr_buf_load(mgr, &info, buf, count); + + /* Release the FPGA manager */ + fpga_mgr_unlock(mgr); + fpga_mgr_put(mgr); + + /* Deallocate the image info if you're done with it */ + fpga_image_info_free(info); + +API for implementing a new FPGA Manager driver +---------------------------------------------- + +.. 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:: drivers/fpga/fpga-mgr.c + :functions: fpga_mgr_create + +.. kernel-doc:: drivers/fpga/fpga-mgr.c + :functions: fpga_mgr_free + +.. kernel-doc:: drivers/fpga/fpga-mgr.c + :functions: fpga_mgr_register + +.. kernel-doc:: drivers/fpga/fpga-mgr.c + :functions: fpga_mgr_unregister + +API for programming a FPGA +-------------------------- + +.. kernel-doc:: include/linux/fpga/fpga-mgr.h + :functions: fpga_image_info + +.. kernel-doc:: include/linux/fpga/fpga-mgr.h + :functions: fpga_mgr_states + +.. kernel-doc:: drivers/fpga/fpga-mgr.c + :functions: fpga_image_info_alloc + +.. kernel-doc:: drivers/fpga/fpga-mgr.c + :functions: fpga_image_info_free + +.. kernel-doc:: drivers/fpga/fpga-mgr.c + :functions: of_fpga_mgr_get + +.. kernel-doc:: drivers/fpga/fpga-mgr.c + :functions: fpga_mgr_get + +.. kernel-doc:: drivers/fpga/fpga-mgr.c + :functions: fpga_mgr_put + +.. kernel-doc:: drivers/fpga/fpga-mgr.c + :functions: fpga_mgr_lock + +.. kernel-doc:: drivers/fpga/fpga-mgr.c + :functions: fpga_mgr_unlock + +.. kernel-doc:: include/linux/fpga/fpga-mgr.h + :functions: fpga_mgr_states + +Note - use :c:func:`fpga_region_program_fpga()` instead of :c:func:`fpga_mgr_load()` + +.. kernel-doc:: drivers/fpga/fpga-mgr.c + :functions: fpga_mgr_load diff --git a/Documentation/driver-api/fpga/index.rst b/Documentation/driver-api/fpga/index.rst index 71e568aea6cd..34b20754517f 100644 --- a/Documentation/driver-api/fpga/index.rst +++ b/Documentation/driver-api/fpga/index.rst @@ -8,3 +8,4 @@ FPGA Subsystem :maxdepth: 2 intro + fpga-mgr diff --git a/Documentation/fpga/fpga-mgr.txt b/Documentation/fpga/fpga-mgr.txt deleted file mode 100644 index 86b6df66a905..000000000000 --- a/Documentation/fpga/fpga-mgr.txt +++ /dev/null @@ -1,218 +0,0 @@ -FPGA Manager Core - -Alan Tull 2015 - -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. - -API Functions: -============== - -To program the FPGA: --------------------- - - int fpga_mgr_load(struct fpga_manager *mgr, - struct fpga_image_info *info); - -Load the FPGA from an image which is indicated in the info. If successful, -the FPGA ends up in operating mode. Return 0 on success or a negative error -code. - -To allocate or free a struct fpga_image_info: ---------------------------------------------- - - struct fpga_image_info *fpga_image_info_alloc(struct device *dev); - - void fpga_image_info_free(struct fpga_image_info *info); - -To get/put a reference to a FPGA manager: ------------------------------------------ - - struct fpga_manager *of_fpga_mgr_get(struct device_node *node); - struct fpga_manager *fpga_mgr_get(struct device *dev); - void fpga_mgr_put(struct fpga_manager *mgr); - -Given a DT node or device, get a reference to a FPGA manager. This pointer -can be saved until you are ready to program the FPGA. fpga_mgr_put releases -the reference. - - -To get exclusive control of a FPGA manager: -------------------------------------------- - - int fpga_mgr_lock(struct fpga_manager *mgr); - void fpga_mgr_unlock(struct fpga_manager *mgr); - -The user should call fpga_mgr_lock and verify that it returns 0 before -attempting to program the FPGA. Likewise, the user should call -fpga_mgr_unlock when done programming the FPGA. - -To alloc/free a FPGA manager struct: ------------------------------------- - - struct fpga_manager *fpga_mgr_create(struct device *dev, - const char *name, - const struct fpga_manager_ops *mops, - void *priv); - void fpga_mgr_free(struct fpga_manager *mgr); - -To register or unregister the low level FPGA-specific driver: -------------------------------------------------------------- - - int fpga_mgr_register(struct fpga_manager *mgr); - - void fpga_mgr_unregister(struct fpga_manager *mgr); - -Use of these functions is described below in "How To Support a new FPGA -device." - - -How to write an image buffer to a supported FPGA -================================================ -#include <linux/fpga/fpga-mgr.h> - -struct fpga_manager *mgr; -struct fpga_image_info *info; -int ret; - -/* - * Get a reference to FPGA manager. The manager is not locked, so you can - * hold onto this reference without it preventing programming. - * - * This example uses the device node of the manager. Alternatively, use - * fpga_mgr_get(dev) instead if you have the device. - */ -mgr = of_fpga_mgr_get(mgr_node); - -/* struct with information about the FPGA image to program. */ -info = fpga_image_info_alloc(dev); - -/* flags indicates whether to do full or partial reconfiguration */ -info->flags = FPGA_MGR_PARTIAL_RECONFIG; - -/* - * At this point, indicate where the image is. This is pseudo-code; you're - * going to use one of these three. - */ -if (image is in a scatter gather table) { - - info->sgt = [your scatter gather table] - -} else if (image is in a buffer) { - - info->buf = [your image buffer] - info->count = [image buffer size] - -} else if (image is in a firmware file) { - - info->firmware_name = devm_kstrdup(dev, firmware_name, GFP_KERNEL); - -} - -/* Get exclusive control of FPGA manager */ -ret = fpga_mgr_lock(mgr); - -/* Load the buffer to the FPGA */ -ret = fpga_mgr_buf_load(mgr, &info, buf, count); - -/* Release the FPGA manager */ -fpga_mgr_unlock(mgr); -fpga_mgr_put(mgr); - -/* Deallocate the image info if you're done with it */ -fpga_image_info_free(info); - -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: - -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_create(dev, "Altera SOCFPGA FPGA Manager", - &socfpga_fpga_ops, priv); - if (!mgr) - return -ENOMEM; - - platform_set_drvdata(pdev, mgr); - - ret = fpga_mgr_register(mgr); - if (ret) - fpga_mgr_free(mgr); - - return ret; -} - -static int socfpga_fpga_remove(struct platform_device *pdev) -{ - struct fpga_manager *mgr = platform_get_drvdata(pdev); - - fpga_mgr_unregister(mgr); - - return 0; -} - - -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 atmost .initial_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 read the hardware FPGA manager and -return a code of type enum fpga_mgr_states. It doesn't result in a change in -hardware state. |