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/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (C) 2022-2024 Linaro Ltd. */
#ifndef _REG_H_
#define _REG_H_
#include <linux/array_size.h>
#include <linux/bits.h>
#include <linux/bug.h>
#include <linux/log2.h>
#include <linux/types.h>
/**
* struct reg - A register descriptor
* @offset: Register offset relative to base of register memory
* @stride: Distance between two instances, if parameterized
* @fcount: Number of entries in the @fmask array
* @fmask: Array of mask values defining position and width of fields
* @name: Upper-case name of the register
*/
struct reg {
u32 offset;
u32 stride;
u32 fcount;
const u32 *fmask; /* BIT(nr) or GENMASK(h, l) */
const char *name;
};
/* Helper macro for defining "simple" (non-parameterized) registers */
#define REG(__NAME, __reg_id, __offset) \
REG_STRIDE(__NAME, __reg_id, __offset, 0)
/* Helper macro for defining parameterized registers, specifying stride */
#define REG_STRIDE(__NAME, __reg_id, __offset, __stride) \
static const struct reg reg_ ## __reg_id = { \
.name = #__NAME, \
.offset = __offset, \
.stride = __stride, \
}
#define REG_FIELDS(__NAME, __name, __offset) \
REG_STRIDE_FIELDS(__NAME, __name, __offset, 0)
#define REG_STRIDE_FIELDS(__NAME, __name, __offset, __stride) \
static const struct reg reg_ ## __name = { \
.name = #__NAME, \
.offset = __offset, \
.stride = __stride, \
.fcount = ARRAY_SIZE(reg_ ## __name ## _fmask), \
.fmask = reg_ ## __name ## _fmask, \
}
/**
* struct regs - Description of registers supported by hardware
* @reg_count: Number of registers in the @reg[] array
* @reg: Array of register descriptors
*/
struct regs {
u32 reg_count;
const struct reg **reg;
};
static inline const struct reg *reg(const struct regs *regs, u32 reg_id)
{
if (WARN(reg_id >= regs->reg_count,
"reg out of range (%u > %u)\n", reg_id, regs->reg_count - 1))
return NULL;
return regs->reg[reg_id];
}
/* Return the field mask for a field in a register, or 0 on error */
static inline u32 reg_fmask(const struct reg *reg, u32 field_id)
{
if (!reg || WARN_ON(field_id >= reg->fcount))
return 0;
return reg->fmask[field_id];
}
/* Return the mask for a single-bit field in a register, or 0 on error */
static inline u32 reg_bit(const struct reg *reg, u32 field_id)
{
u32 fmask = reg_fmask(reg, field_id);
if (WARN_ON(!is_power_of_2(fmask)))
return 0;
return fmask;
}
/* Return the maximum value representable by the given field; always 2^n - 1 */
static inline u32 reg_field_max(const struct reg *reg, u32 field_id)
{
u32 fmask = reg_fmask(reg, field_id);
return fmask ? fmask >> __ffs(fmask) : 0;
}
/* Encode a value into the given field of a register */
static inline u32 reg_encode(const struct reg *reg, u32 field_id, u32 val)
{
u32 fmask = reg_fmask(reg, field_id);
if (!fmask)
return 0;
val <<= __ffs(fmask);
if (WARN_ON(val & ~fmask))
return 0;
return val;
}
/* Given a register value, decode (extract) the value in the given field */
static inline u32 reg_decode(const struct reg *reg, u32 field_id, u32 val)
{
u32 fmask = reg_fmask(reg, field_id);
return fmask ? (val & fmask) >> __ffs(fmask) : 0;
}
/* Returns 0 for NULL reg; warning should have already been issued */
static inline u32 reg_offset(const struct reg *reg)
{
return reg ? reg->offset : 0;
}
/* Returns 0 for NULL reg; warning should have already been issued */
static inline u32 reg_n_offset(const struct reg *reg, u32 n)
{
return reg ? reg->offset + n * reg->stride : 0;
}
#endif /* _REG_H_ */
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