From 7681f64e6404edbca2f67501c98d596e5c307993 Mon Sep 17 00:00:00 2001 From: Shubhrajyoti Datta Date: Mon, 6 Jan 2025 13:59:37 +0530 Subject: [PATCH] clk: clocking-wizard: calculate dividers fractional parts Calculate dividers fractional parts to optimally modulate output frequency. Clocking wizard supports having multiplier m and divisors d and o. Currently the fractional parts of m and o are not utilised. For the pixel clock usecases a higher accuracy is needed.. Adding support for m and o to have fractional values. Co-developed-by: Anatoliy Klymenko Signed-off-by: Anatoliy Klymenko Signed-off-by: Shubhrajyoti Datta Tested-by: Anatoliy Klymenko Link: https://lore.kernel.org/r/20250106082937.29555-1-shubhrajyoti.datta@amd.com Signed-off-by: Stephen Boyd --- drivers/clk/xilinx/clk-xlnx-clock-wizard.c | 121 ++++++++++++--------- 1 file changed, 69 insertions(+), 52 deletions(-) diff --git a/drivers/clk/xilinx/clk-xlnx-clock-wizard.c b/drivers/clk/xilinx/clk-xlnx-clock-wizard.c index b2233d3ff9a99..bbf7714480e7b 100644 --- a/drivers/clk/xilinx/clk-xlnx-clock-wizard.c +++ b/drivers/clk/xilinx/clk-xlnx-clock-wizard.c @@ -52,6 +52,8 @@ #define WZRD_CLKFBOUT_MULT_SHIFT 8 #define WZRD_CLKFBOUT_MULT_MASK (0xff << WZRD_CLKFBOUT_MULT_SHIFT) +#define WZRD_CLKFBOUT_MULT_FRAC_MASK GENMASK(25, 16) +#define WZRD_CLKFBOUT_O_MASK GENMASK(7, 0) #define WZRD_CLKFBOUT_L_SHIFT 0 #define WZRD_CLKFBOUT_H_SHIFT 8 #define WZRD_CLKFBOUT_L_MASK GENMASK(7, 0) @@ -87,14 +89,14 @@ #define DIV_O 0x01 #define DIV_ALL 0x03 -#define WZRD_M_MIN 2 -#define WZRD_M_MAX 128 -#define WZRD_D_MIN 1 -#define WZRD_D_MAX 106 -#define WZRD_VCO_MIN 800000000 -#define WZRD_VCO_MAX 1600000000 -#define WZRD_O_MIN 1 -#define WZRD_O_MAX 128 +#define WZRD_M_MIN 2ULL +#define WZRD_M_MAX 128ULL +#define WZRD_D_MIN 1ULL +#define WZRD_D_MAX 106ULL +#define WZRD_VCO_MIN 800000000ULL +#define WZRD_VCO_MAX 1600000000ULL +#define WZRD_O_MIN 2ULL +#define WZRD_O_MAX 128ULL #define VER_WZRD_M_MIN 4 #define VER_WZRD_M_MAX 432 #define VER_WZRD_D_MIN 1 @@ -153,8 +155,10 @@ struct clk_wzrd { * @flags: clk_wzrd divider flags * @table: array of value/divider pairs, last entry should have div = 0 * @m: value of the multiplier + * @m_frac: fractional value of the multiplier * @d: value of the common divider * @o: value of the leaf divider + * @o_frac: value of the fractional leaf divider * @lock: register lock */ struct clk_wzrd_divider { @@ -166,8 +170,10 @@ struct clk_wzrd_divider { u8 flags; const struct clk_div_table *table; u32 m; + u32 m_frac; u32 d; u32 o; + u32 o_frac; spinlock_t *lock; /* divider lock */ }; @@ -372,38 +378,40 @@ static int clk_wzrd_get_divisors(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate) { struct clk_wzrd_divider *divider = to_clk_wzrd_divider(hw); - u64 vco_freq, freq, diff, vcomin, vcomax; - u32 m, d, o; - u32 mmin, mmax, dmin, dmax, omin, omax; + u64 vco_freq, freq, diff, vcomin, vcomax, best_diff = -1ULL; + u64 m, d, o; + u64 mmin, mmax, dmin, dmax, omin, omax, mdmin, mdmax; - mmin = WZRD_M_MIN; - mmax = WZRD_M_MAX; + mmin = WZRD_M_MIN << 3; + mmax = WZRD_M_MAX << 3; dmin = WZRD_D_MIN; dmax = WZRD_D_MAX; - omin = WZRD_O_MIN; - omax = WZRD_O_MAX; - vcomin = WZRD_VCO_MIN; - vcomax = WZRD_VCO_MAX; + omin = WZRD_O_MIN << 3; + omax = WZRD_O_MAX << 3; + vcomin = WZRD_VCO_MIN << 3; + vcomax = WZRD_VCO_MAX << 3; for (m = mmin; m <= mmax; m++) { - for (d = dmin; d <= dmax; d++) { - vco_freq = DIV_ROUND_CLOSEST((parent_rate * m), d); - if (vco_freq >= vcomin && vco_freq <= vcomax) { - for (o = omin; o <= omax; o++) { - freq = DIV_ROUND_CLOSEST_ULL(vco_freq, o); - diff = abs(freq - rate); - - if (diff < WZRD_MIN_ERR) { - divider->m = m; - divider->d = d; - divider->o = o; - return 0; - } - } + mdmin = max(dmin, div64_u64(parent_rate * m + vcomax / 2, vcomax)); + mdmax = min(dmax, div64_u64(parent_rate * m + vcomin / 2, vcomin)); + for (d = mdmin; d <= mdmax; d++) { + vco_freq = DIV_ROUND_CLOSEST_ULL((parent_rate * m), d); + o = DIV_ROUND_CLOSEST_ULL(vco_freq, rate); + if (o < omin || o > omax) + continue; + freq = DIV_ROUND_CLOSEST_ULL(vco_freq, o); + diff = freq - rate; + if (diff < best_diff) { + best_diff = diff; + divider->m = m >> 3; + divider->m_frac = (m - (divider->m << 3)) * 125; + divider->d = d; + divider->o = o >> 3; + divider->o_frac = (o - (divider->o << 3)) * 125; } } } - return -EBUSY; + return best_diff < WZRD_MIN_ERR ? 0 : -EBUSY; } static int clk_wzrd_reconfig(struct clk_wzrd_divider *divider, void __iomem *div_addr) @@ -496,33 +504,22 @@ static int clk_wzrd_dynamic_all_nolock(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate) { struct clk_wzrd_divider *divider = to_clk_wzrd_divider(hw); - unsigned long vco_freq, rate_div, clockout0_div; void __iomem *div_addr; - u32 reg, pre, f; + u32 reg; int err; err = clk_wzrd_get_divisors(hw, rate, parent_rate); if (err) return err; - vco_freq = DIV_ROUND_CLOSEST(parent_rate * divider->m, divider->d); - rate_div = DIV_ROUND_CLOSEST_ULL((vco_freq * WZRD_FRAC_POINTS), rate); - - clockout0_div = div_u64(rate_div, WZRD_FRAC_POINTS); - - pre = DIV_ROUND_CLOSEST_ULL(vco_freq * WZRD_FRAC_POINTS, rate); - f = (pre - (clockout0_div * WZRD_FRAC_POINTS)); - f &= WZRD_CLKOUT_FRAC_MASK; - - reg = FIELD_PREP(WZRD_CLKOUT_DIVIDE_MASK, clockout0_div) | - FIELD_PREP(WZRD_CLKOUT0_FRAC_MASK, f); + reg = FIELD_PREP(WZRD_CLKOUT_DIVIDE_MASK, divider->o) | + FIELD_PREP(WZRD_CLKOUT0_FRAC_MASK, divider->o_frac); writel(reg, divider->base + WZRD_CLK_CFG_REG(0, 2)); - /* Set divisor and clear phase offset */ reg = FIELD_PREP(WZRD_CLKFBOUT_MULT_MASK, divider->m) | + FIELD_PREP(WZRD_CLKFBOUT_MULT_FRAC_MASK, divider->m_frac) | FIELD_PREP(WZRD_DIVCLK_DIVIDE_MASK, divider->d); writel(reg, divider->base + WZRD_CLK_CFG_REG(0, 0)); - writel(divider->o, divider->base + WZRD_CLK_CFG_REG(0, 2)); writel(0, divider->base + WZRD_CLK_CFG_REG(0, 3)); div_addr = divider->base + WZRD_DR_INIT_REG_OFFSET; return clk_wzrd_reconfig(divider, div_addr); @@ -564,18 +561,19 @@ static unsigned long clk_wzrd_recalc_rate_all(struct clk_hw *hw, unsigned long parent_rate) { struct clk_wzrd_divider *divider = to_clk_wzrd_divider(hw); - u32 m, d, o, div, reg, f; + u32 m, d, o, reg, f, mf; + u64 mul; reg = readl(divider->base + WZRD_CLK_CFG_REG(0, 0)); d = FIELD_GET(WZRD_DIVCLK_DIVIDE_MASK, reg); m = FIELD_GET(WZRD_CLKFBOUT_MULT_MASK, reg); + mf = FIELD_GET(WZRD_CLKFBOUT_MULT_FRAC_MASK, reg); reg = readl(divider->base + WZRD_CLK_CFG_REG(0, 2)); o = FIELD_GET(WZRD_DIVCLK_DIVIDE_MASK, reg); f = FIELD_GET(WZRD_CLKOUT0_FRAC_MASK, reg); - div = DIV_ROUND_CLOSEST(d * (WZRD_FRAC_POINTS * o + f), WZRD_FRAC_POINTS); - return divider_recalc_rate(hw, parent_rate * m, div, divider->table, - divider->flags, divider->width); + mul = m * 1000 + mf; + return DIV_ROUND_CLOSEST_ULL(parent_rate * mul, d * (o * 1000 + f)); } static unsigned long clk_wzrd_recalc_rate_all_ver(struct clk_hw *hw, @@ -646,6 +644,25 @@ static unsigned long clk_wzrd_recalc_rate_all_ver(struct clk_hw *hw, static long clk_wzrd_round_rate_all(struct clk_hw *hw, unsigned long rate, unsigned long *prate) +{ + struct clk_wzrd_divider *divider = to_clk_wzrd_divider(hw); + u32 m, d, o; + int err; + + err = clk_wzrd_get_divisors(hw, rate, *prate); + if (err) + return err; + + m = divider->m; + d = divider->d; + o = divider->o; + + rate = div_u64(*prate * (m * 1000 + divider->m_frac), d * (o * 1000 + divider->o_frac)); + return rate; +} + +static long clk_wzrd_ver_round_rate_all(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) { struct clk_wzrd_divider *divider = to_clk_wzrd_divider(hw); unsigned long int_freq; @@ -678,7 +695,7 @@ static const struct clk_ops clk_wzrd_ver_divider_ops = { }; static const struct clk_ops clk_wzrd_ver_div_all_ops = { - .round_rate = clk_wzrd_round_rate_all, + .round_rate = clk_wzrd_ver_round_rate_all, .set_rate = clk_wzrd_dynamic_all_ver, .recalc_rate = clk_wzrd_recalc_rate_all_ver, };