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![Alessandro Rubini](/assets/img/avatar_default.png)
This is selected sections of the current manual for fmc-bus, as developed outside of the kernel before submission. Like the other patches in this set, it corresponds to commit ab23167f of the repository at ohwr.org Signed-off-by: Alessandro Rubini <rubini@gnudd.com> Acked-by: Juan David Gonzalez Cobas <dcobas@cern.ch> Acked-by: Emilio G. Cota <cota@braap.org> Acked-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com> Acked-by: Rob Landley <rob@landley.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
47 lines
2.3 KiB
Text
47 lines
2.3 KiB
Text
Functions Exported by fmc.ko
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****************************
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The FMC core exports the usual 4 functions that are needed for a bus to
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work, and a few more:
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int fmc_driver_register(struct fmc_driver *drv);
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void fmc_driver_unregister(struct fmc_driver *drv);
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int fmc_device_register(struct fmc_device *fmc);
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void fmc_device_unregister(struct fmc_device *fmc);
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int fmc_device_register_n(struct fmc_device **fmc, int n);
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void fmc_device_unregister_n(struct fmc_device **fmc, int n);
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uint32_t fmc_readl(struct fmc_device *fmc, int offset);
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void fmc_writel(struct fmc_device *fmc, uint32_t val, int off);
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void *fmc_get_drvdata(struct fmc_device *fmc);
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void fmc_set_drvdata(struct fmc_device *fmc, void *data);
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int fmc_reprogram(struct fmc_device *f, struct fmc_driver *d, char *gw,
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int sdb_entry);
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The data structure that describe a device is detailed in *note FMC
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Device::, the one that describes a driver is detailed in *note FMC
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Driver::. Please note that structures of type fmc_device must be
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allocated by the caller, but must not be released after unregistering.
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The fmc-bus itself takes care of releasing the structure when their use
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count reaches zero - actually, the device model does that in lieu of us.
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The functions to register and unregister n devices are meant to be used
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by carriers that host more than one mezzanine. The devices must all be
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registered at the same time because if the FPGA is reprogrammed, all
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devices in the array are affected. Usually, the driver matching the
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first device will reprogram the FPGA, so other devices must know they
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are already driven by a reprogrammed FPGA.
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If a carrier hosts slots that are driven by different FPGA devices, it
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should register as a group only mezzanines that are driven by the same
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FPGA, for the reason outlined above.
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Finally, the fmc_reprogram function calls the reprogram method (see
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*note The API Offered by Carriers:: and also scans the memory area for
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an SDB tree. You can pass -1 as sdb_entry to disable such scan.
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Otherwise, the function fails if no tree is found at the specified
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entry point. The function is meant to factorize common code, and by
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the time you read this it is already used by the spec-sw and fine-delay
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modules.
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