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56 lines
1.5 KiB
C
56 lines
1.5 KiB
C
/*
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* include/ubb/mmcclk.h - Calculate MMC bus clock speed
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*
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* Written 2013 by Werner Almesberger
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* Copyright 2013 Werner Almesberger
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#ifndef UBB_MMCCLK_H
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#define UBB_MMCCLK_H
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#include <stdint.h>
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#define BEN_PLL_CLK_HZ 336000000
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/*
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* By default (flags = 0), only clocks that can be used with any mode of
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* operation will be generated. The following flags also include clocks ...
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*/
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#define MMCCLK_FLAG_RD_ONLY (1 << 0) /* not suitable for writing */
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#define MMCCLK_FLAG_WR_ONLY (1 << 1) /* not suitable for reading */
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#define MMCCLK_FLAG_INTERNAL (1 << 2) /* not suitable for bus use */
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#define MMCCLK_FLAG_UNSAFE (1 << 3) /* that may hang the MSC */
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#define MMCCLK_FLAG_ALL (1 << 4) /* that will hang the MSC */
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/*
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* For now, only MMCCLK_FLAG_UNSAFE and MMCCLK_FLAG_ALL are implemented, but
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* further research may also reveal limits that depend on the type of
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* operation.
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*/
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struct mmcclk {
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int sys_clk_hz; /* system clock speed in Hz */
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double bus_clk_hz; /* MMC bus clock in Hz */
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uint32_t clkdiv; /* MSC controller clock */
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uint32_t clkrt; /* bus clock divider */
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unsigned flags;
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};
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void mmcclk_first(struct mmcclk *dsc, int sys_clk_hz, unsigned flags);
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int mmcclk_next(struct mmcclk *dsc);
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void mmcclk_start(struct mmcclk *dsc);
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void mmcclk_stop(void);
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#endif /* !UBB_MMCCLK_H */
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