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Diffstat (limited to 'kernel/Documentation/fmc/API.txt')
| -rw-r--r-- | kernel/Documentation/fmc/API.txt | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/kernel/Documentation/fmc/API.txt b/kernel/Documentation/fmc/API.txt new file mode 100644 index 000000000..06b06b92c --- /dev/null +++ b/kernel/Documentation/fmc/API.txt @@ -0,0 +1,47 @@ +Functions Exported by fmc.ko +**************************** + +The FMC core exports the usual 4 functions that are needed for a bus to +work, and a few more: + + int fmc_driver_register(struct fmc_driver *drv); + void fmc_driver_unregister(struct fmc_driver *drv); + int fmc_device_register(struct fmc_device *fmc); + void fmc_device_unregister(struct fmc_device *fmc); + + int fmc_device_register_n(struct fmc_device **fmc, int n); + void fmc_device_unregister_n(struct fmc_device **fmc, int n); + + uint32_t fmc_readl(struct fmc_device *fmc, int offset); + void fmc_writel(struct fmc_device *fmc, uint32_t val, int off); + void *fmc_get_drvdata(struct fmc_device *fmc); + void fmc_set_drvdata(struct fmc_device *fmc, void *data); + + int fmc_reprogram(struct fmc_device *f, struct fmc_driver *d, char *gw, + int sdb_entry); + +The data structure that describe a device is detailed in *note FMC +Device::, the one that describes a driver is detailed in *note FMC +Driver::. Please note that structures of type fmc_device must be +allocated by the caller, but must not be released after unregistering. +The fmc-bus itself takes care of releasing the structure when their use +count reaches zero - actually, the device model does that in lieu of us. + +The functions to register and unregister n devices are meant to be used +by carriers that host more than one mezzanine. The devices must all be +registered at the same time because if the FPGA is reprogrammed, all +devices in the array are affected. Usually, the driver matching the +first device will reprogram the FPGA, so other devices must know they +are already driven by a reprogrammed FPGA. + +If a carrier hosts slots that are driven by different FPGA devices, it +should register as a group only mezzanines that are driven by the same +FPGA, for the reason outlined above. + +Finally, the fmc_reprogram function calls the reprogram method (see +*note The API Offered by Carriers:: and also scans the memory area for +an SDB tree. You can pass -1 as sdb_entry to disable such scan. +Otherwise, the function fails if no tree is found at the specified +entry point. The function is meant to factorize common code, and by +the time you read this it is already used by the spec-sw and fine-delay +modules. |