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/*
* This file is part of the coreboot project.
*
* Copyright 2018 SiFive, Inc
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef __SOC_SIFIVE_HIFIVE_U_SPI_INTERNAL_H__
#define __SOC_SIFIVE_HIFIVE_U_SPI_INTERNAL_H__
#include <stdint.h>
#define _ASSERT_SIZEOF(type, size) _Static_assert( \
sizeof(type) == (size), \
#type " must be " #size " bytes wide")
#define FU540_SPI_CSMODE_AUTO 0
#define FU540_SPI_CSMODE_HOLD 2
#define FU540_SPI_CSMODE_OFF 3
typedef union {
struct {
uint32_t pha : 1;
uint32_t pol : 1;
uint32_t reserved : 30;
};
uint32_t raw_bits;
} spi_reg_sckmode;
_ASSERT_SIZEOF(spi_reg_sckmode, 4);
typedef union {
struct {
uint32_t mode : 2;
uint32_t reserved : 30;
};
uint32_t raw_bits;
} spi_reg_csmode;
_ASSERT_SIZEOF(spi_reg_csmode, 4);
typedef union {
struct {
uint32_t cssck : 8;
uint32_t reserved0 : 8;
uint32_t sckcs : 8;
uint32_t reserved1 : 8;
};
uint32_t raw_bits;
} spi_reg_delay0;
_ASSERT_SIZEOF(spi_reg_delay0, 4);
typedef union {
struct {
uint32_t intercs : 8;
uint32_t reserved0 : 8;
uint32_t interxfr : 8;
uint32_t reserved1 : 8;
};
uint32_t raw_bits;
} spi_reg_delay1;
_ASSERT_SIZEOF(spi_reg_delay1, 4);
typedef union {
struct {
uint32_t proto : 2;
uint32_t endian : 1;
uint32_t dir : 1;
uint32_t reserved0 : 12;
uint32_t len : 4;
uint32_t reserved1 : 12;
};
uint32_t raw_bits;
} spi_reg_fmt;
_ASSERT_SIZEOF(spi_reg_fmt, 4);
typedef union {
struct {
uint32_t data : 8;
uint32_t reserved : 23;
uint32_t full : 1;
};
uint32_t raw_bits;
} spi_reg_txdata;
_ASSERT_SIZEOF(spi_reg_txdata, 4);
typedef union {
struct {
uint32_t data : 8;
uint32_t reserved : 23;
uint32_t empty : 1;
};
uint32_t raw_bits;
} spi_reg_rxdata;
_ASSERT_SIZEOF(spi_reg_rxdata, 4);
typedef union {
struct {
uint32_t txmark : 3;
uint32_t reserved : 29;
};
uint32_t raw_bits;
} spi_reg_txmark;
_ASSERT_SIZEOF(spi_reg_txmark, 4);
typedef union {
struct {
uint32_t rxmark : 3;
uint32_t reserved : 29;
};
uint32_t raw_bits;
} spi_reg_rxmark;
_ASSERT_SIZEOF(spi_reg_rxmark, 4);
typedef union {
struct {
uint32_t en : 1;
uint32_t reserved : 31;
};
uint32_t raw_bits;
} spi_reg_fctrl;
_ASSERT_SIZEOF(spi_reg_fctrl, 4);
typedef union {
struct {
uint32_t cmd_en : 1;
uint32_t addr_len : 3;
uint32_t pad_cnt : 4;
uint32_t command_proto : 2;
uint32_t addr_proto : 2;
uint32_t data_proto : 2;
uint32_t reserved : 2;
uint32_t command_code : 8;
uint32_t pad_code : 8;
};
uint32_t raw_bits;
} spi_reg_ffmt;
_ASSERT_SIZEOF(spi_reg_ffmt, 4);
typedef union {
struct {
uint32_t txwm : 1;
uint32_t rxwm : 1;
uint32_t reserved : 30;
};
uint32_t raw_bits;
} spi_reg_ie;
typedef spi_reg_ie spi_reg_ip;
_ASSERT_SIZEOF(spi_reg_ie, 4);
_ASSERT_SIZEOF(spi_reg_ip, 4);
#undef _ASSERT_SIZEOF
/**
* SPI control register memory map.
*
* All functions take a pointer to a SPI device's control registers.
*/
struct spi_ctrl {
uint32_t sckdiv;
spi_reg_sckmode sckmode;
uint32_t reserved08;
uint32_t reserved0c;
uint32_t csid;
uint32_t csdef;
spi_reg_csmode csmode;
uint32_t reserved1c;
uint32_t reserved20;
uint32_t reserved24;
spi_reg_delay0 delay0;
spi_reg_delay1 delay1;
uint32_t reserved30;
uint32_t reserved34;
uint32_t reserved38;
uint32_t reserved3c;
spi_reg_fmt fmt;
uint32_t reserved44;
spi_reg_txdata txdata;
spi_reg_rxdata rxdata;
spi_reg_txmark txmark;
spi_reg_rxmark rxmark;
uint32_t reserved58;
uint32_t reserved5c;
spi_reg_fctrl fctrl;
spi_reg_ffmt ffmt;
uint32_t reserved68;
uint32_t reserved6c;
spi_reg_ie ie;
spi_reg_ip ip;
};
/**
* Get smallest clock divisor that divides input_khz to a quotient less than or
* equal to max_target_khz;
*/
static inline unsigned int
spi_min_clk_divisor(unsigned int input_khz, unsigned int max_target_khz)
{
// f_sck = f_in / (2 * (div + 1)) => div = (f_in / (2*f_sck)) - 1
//
// The nearest integer solution for div requires rounding up as to not
// exceed max_target_khz.
//
// div = ceil(f_in / (2*f_sck)) - 1
// = floor((f_in - 1 + 2*f_sck) / (2*f_sck)) - 1
//
// This should not overflow as long as (f_in - 1 + 2*f_sck) does not
// exceed 2^32 - 1, which is unlikely since we represent frequencies
// in kHz.
unsigned int quotient =
(input_khz + 2 * max_target_khz - 1) / (2 * max_target_khz);
// Avoid underflow
if (quotient == 0)
return 0;
return quotient - 1;
}
#endif /* __SOC_SIFIVE_HIFIVE_U_SPI_INTERNAL_H__ */
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