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-rw-r--r--drivers/clk/zynqmp/divider.c288
1 files changed, 288 insertions, 0 deletions
diff --git a/drivers/clk/zynqmp/divider.c b/drivers/clk/zynqmp/divider.c
new file mode 100644
index 000000000..acfd4878c
--- /dev/null
+++ b/drivers/clk/zynqmp/divider.c
@@ -0,0 +1,288 @@
+// 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)
+ */
+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_warn_once("%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);
+}
+
+/**
+ * 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;
+ u8 width;
+
+ /* 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_warn_once("%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);
+ }
+
+ width = fls(divider->max_div);
+
+ rate = divider_round_rate(hw, rate, prate, NULL, width, divider->flags);
+
+ if (divider->is_frac && (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && (rate % *prate))
+ *prate = rate;
+
+ 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_warn_once("%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,
+};
+
+/**
+ * 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];
+}
+
+/**
+ * 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;
+ init.ops = &zynqmp_clk_divider_ops;
+ /* CLK_FRAC is not defined in the common clk framework */
+ init.flags = nodes->flag & ~CLK_FRAC;
+ 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 = 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;
+}