diff options
Diffstat (limited to 'drivers/clk/zynqmp/divider.c')
| -rw-r--r-- | drivers/clk/zynqmp/divider.c | 377 |
1 files changed, 377 insertions, 0 deletions
diff --git a/drivers/clk/zynqmp/divider.c b/drivers/clk/zynqmp/divider.c new file mode 100644 index 000000000..33a3b2a22 --- /dev/null +++ b/drivers/clk/zynqmp/divider.c @@ -0,0 +1,377 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Zynq UltraScale+ MPSoC Divider support + * + * Copyright (C) 2016-2019 Xilinx + * + * Adjustable divider clock implementation + */ + +#include <linux/clk.h> +#include <linux/clk-provider.h> +#include <linux/slab.h> +#include "clk-zynqmp.h" + +/* + * DOC: basic adjustable divider clock that cannot gate + * + * Traits of this clock: + * prepare - clk_prepare only ensures that parents are prepared + * enable - clk_enable only ensures that parents are enabled + * rate - rate is adjustable. clk->rate = ceiling(parent->rate / divisor) + * parent - fixed parent. No clk_set_parent support + */ + +#define to_zynqmp_clk_divider(_hw) \ + container_of(_hw, struct zynqmp_clk_divider, hw) + +#define CLK_FRAC BIT(13) /* has a fractional parent */ +#define CUSTOM_FLAG_CLK_FRAC BIT(0) /* has a fractional parent in custom type flag */ + +/** + * struct zynqmp_clk_divider - adjustable divider clock + * @hw: handle between common and hardware-specific interfaces + * @flags: Hardware specific flags + * @is_frac: The divider is a fractional divider + * @clk_id: Id of clock + * @div_type: divisor type (TYPE_DIV1 or TYPE_DIV2) + * @max_div: maximum supported divisor (fetched from firmware) + */ +struct zynqmp_clk_divider { + struct clk_hw hw; + u8 flags; + bool is_frac; + u32 clk_id; + u32 div_type; + u16 max_div; +}; + +static inline int zynqmp_divider_get_val(unsigned long parent_rate, + unsigned long rate, u16 flags) +{ + int up, down; + unsigned long up_rate, down_rate; + + if (flags & CLK_DIVIDER_POWER_OF_TWO) { + up = DIV_ROUND_UP_ULL((u64)parent_rate, rate); + down = DIV_ROUND_DOWN_ULL((u64)parent_rate, rate); + + up = __roundup_pow_of_two(up); + down = __rounddown_pow_of_two(down); + + up_rate = DIV_ROUND_UP_ULL((u64)parent_rate, up); + down_rate = DIV_ROUND_UP_ULL((u64)parent_rate, down); + + return (rate - up_rate) <= (down_rate - rate) ? up : down; + + } else { + return DIV_ROUND_CLOSEST(parent_rate, rate); + } +} + +/** + * zynqmp_clk_divider_recalc_rate() - Recalc rate of divider clock + * @hw: handle between common and hardware-specific interfaces + * @parent_rate: rate of parent clock + * + * Return: 0 on success else error+reason + */ +static unsigned long zynqmp_clk_divider_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw); + const char *clk_name = clk_hw_get_name(hw); + u32 clk_id = divider->clk_id; + u32 div_type = divider->div_type; + u32 div, value; + int ret; + + ret = zynqmp_pm_clock_getdivider(clk_id, &div); + + if (ret) + pr_debug("%s() get divider failed for %s, ret = %d\n", + __func__, clk_name, ret); + + if (div_type == TYPE_DIV1) + value = div & 0xFFFF; + else + value = div >> 16; + + if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) + value = 1 << value; + + if (!value) { + WARN(!(divider->flags & CLK_DIVIDER_ALLOW_ZERO), + "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n", + clk_name); + return parent_rate; + } + + return DIV_ROUND_UP_ULL(parent_rate, value); +} + +static void zynqmp_get_divider2_val(struct clk_hw *hw, + unsigned long rate, + struct zynqmp_clk_divider *divider, + u32 *bestdiv) +{ + int div1; + int div2; + long error = LONG_MAX; + unsigned long div1_prate; + struct clk_hw *div1_parent_hw; + struct zynqmp_clk_divider *pdivider; + struct clk_hw *div2_parent_hw = clk_hw_get_parent(hw); + + if (!div2_parent_hw) + return; + + pdivider = to_zynqmp_clk_divider(div2_parent_hw); + if (!pdivider) + return; + + div1_parent_hw = clk_hw_get_parent(div2_parent_hw); + if (!div1_parent_hw) + return; + + div1_prate = clk_hw_get_rate(div1_parent_hw); + *bestdiv = 1; + for (div1 = 1; div1 <= pdivider->max_div;) { + for (div2 = 1; div2 <= divider->max_div;) { + long new_error = ((div1_prate / div1) / div2) - rate; + + if (abs(new_error) < abs(error)) { + *bestdiv = div2; + error = new_error; + } + if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) + div2 = div2 << 1; + else + div2++; + } + if (pdivider->flags & CLK_DIVIDER_POWER_OF_TWO) + div1 = div1 << 1; + else + div1++; + } +} + +/** + * zynqmp_clk_divider_round_rate() - Round rate of divider clock + * @hw: handle between common and hardware-specific interfaces + * @rate: rate of clock to be set + * @prate: rate of parent clock + * + * Return: 0 on success else error+reason + */ +static long zynqmp_clk_divider_round_rate(struct clk_hw *hw, + unsigned long rate, + unsigned long *prate) +{ + struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw); + const char *clk_name = clk_hw_get_name(hw); + u32 clk_id = divider->clk_id; + u32 div_type = divider->div_type; + u32 bestdiv; + int ret; + + /* if read only, just return current value */ + if (divider->flags & CLK_DIVIDER_READ_ONLY) { + ret = zynqmp_pm_clock_getdivider(clk_id, &bestdiv); + + if (ret) + pr_debug("%s() get divider failed for %s, ret = %d\n", + __func__, clk_name, ret); + if (div_type == TYPE_DIV1) + bestdiv = bestdiv & 0xFFFF; + else + bestdiv = bestdiv >> 16; + + if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) + bestdiv = 1 << bestdiv; + + return DIV_ROUND_UP_ULL((u64)*prate, bestdiv); + } + + bestdiv = zynqmp_divider_get_val(*prate, rate, divider->flags); + + /* + * In case of two divisors, compute best divider values and return + * divider2 value based on compute value. div1 will be automatically + * set to optimum based on required total divider value. + */ + if (div_type == TYPE_DIV2 && + (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) { + zynqmp_get_divider2_val(hw, rate, divider, &bestdiv); + } + + if ((clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && divider->is_frac) + bestdiv = rate % *prate ? 1 : bestdiv; + + bestdiv = min_t(u32, bestdiv, divider->max_div); + *prate = rate * bestdiv; + + return rate; +} + +/** + * zynqmp_clk_divider_set_rate() - Set rate of divider clock + * @hw: handle between common and hardware-specific interfaces + * @rate: rate of clock to be set + * @parent_rate: rate of parent clock + * + * Return: 0 on success else error+reason + */ +static int zynqmp_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw); + const char *clk_name = clk_hw_get_name(hw); + u32 clk_id = divider->clk_id; + u32 div_type = divider->div_type; + u32 value, div; + int ret; + + value = zynqmp_divider_get_val(parent_rate, rate, divider->flags); + if (div_type == TYPE_DIV1) { + div = value & 0xFFFF; + div |= 0xffff << 16; + } else { + div = 0xffff; + div |= value << 16; + } + + if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) + div = __ffs(div); + + ret = zynqmp_pm_clock_setdivider(clk_id, div); + + if (ret) + pr_debug("%s() set divider failed for %s, ret = %d\n", + __func__, clk_name, ret); + + return ret; +} + +static const struct clk_ops zynqmp_clk_divider_ops = { + .recalc_rate = zynqmp_clk_divider_recalc_rate, + .round_rate = zynqmp_clk_divider_round_rate, + .set_rate = zynqmp_clk_divider_set_rate, +}; + +static const struct clk_ops zynqmp_clk_divider_ro_ops = { + .recalc_rate = zynqmp_clk_divider_recalc_rate, + .round_rate = zynqmp_clk_divider_round_rate, +}; + +/** + * zynqmp_clk_get_max_divisor() - Get maximum supported divisor from firmware. + * @clk_id: Id of clock + * @type: Divider type + * + * Return: Maximum divisor of a clock if query data is successful + * U16_MAX in case of query data is not success + */ +static u32 zynqmp_clk_get_max_divisor(u32 clk_id, u32 type) +{ + struct zynqmp_pm_query_data qdata = {0}; + u32 ret_payload[PAYLOAD_ARG_CNT]; + int ret; + + qdata.qid = PM_QID_CLOCK_GET_MAX_DIVISOR; + qdata.arg1 = clk_id; + qdata.arg2 = type; + ret = zynqmp_pm_query_data(qdata, ret_payload); + /* + * To maintain backward compatibility return maximum possible value + * (0xFFFF) if query for max divisor is not successful. + */ + if (ret) + return U16_MAX; + + return ret_payload[1]; +} + +static inline unsigned long zynqmp_clk_map_divider_ccf_flags( + const u32 zynqmp_type_flag) +{ + unsigned long ccf_flag = 0; + + if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_ONE_BASED) + ccf_flag |= CLK_DIVIDER_ONE_BASED; + if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_POWER_OF_TWO) + ccf_flag |= CLK_DIVIDER_POWER_OF_TWO; + if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_ALLOW_ZERO) + ccf_flag |= CLK_DIVIDER_ALLOW_ZERO; + if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_POWER_OF_TWO) + ccf_flag |= CLK_DIVIDER_HIWORD_MASK; + if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_ROUND_CLOSEST) + ccf_flag |= CLK_DIVIDER_ROUND_CLOSEST; + if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_READ_ONLY) + ccf_flag |= CLK_DIVIDER_READ_ONLY; + if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_MAX_AT_ZERO) + ccf_flag |= CLK_DIVIDER_MAX_AT_ZERO; + + return ccf_flag; +} + +/** + * zynqmp_clk_register_divider() - Register a divider clock + * @name: Name of this clock + * @clk_id: Id of clock + * @parents: Name of this clock's parents + * @num_parents: Number of parents + * @nodes: Clock topology node + * + * Return: clock hardware to registered clock divider + */ +struct clk_hw *zynqmp_clk_register_divider(const char *name, + u32 clk_id, + const char * const *parents, + u8 num_parents, + const struct clock_topology *nodes) +{ + struct zynqmp_clk_divider *div; + struct clk_hw *hw; + struct clk_init_data init; + int ret; + + /* allocate the divider */ + div = kzalloc(sizeof(*div), GFP_KERNEL); + if (!div) + return ERR_PTR(-ENOMEM); + + init.name = name; + if (nodes->type_flag & CLK_DIVIDER_READ_ONLY) + init.ops = &zynqmp_clk_divider_ro_ops; + else + init.ops = &zynqmp_clk_divider_ops; + + init.flags = zynqmp_clk_map_common_ccf_flags(nodes->flag); + + init.parent_names = parents; + init.num_parents = 1; + + /* struct clk_divider assignments */ + div->is_frac = !!((nodes->flag & CLK_FRAC) | + (nodes->custom_type_flag & CUSTOM_FLAG_CLK_FRAC)); + div->flags = zynqmp_clk_map_divider_ccf_flags(nodes->type_flag); + div->hw.init = &init; + div->clk_id = clk_id; + div->div_type = nodes->type; + + /* + * To achieve best possible rate, maximum limit of divider is required + * while computation. + */ + div->max_div = zynqmp_clk_get_max_divisor(clk_id, nodes->type); + + hw = &div->hw; + ret = clk_hw_register(NULL, hw); + if (ret) { + kfree(div); + hw = ERR_PTR(ret); + } + + return hw; +} |