1 files changed, 251 insertions, 0 deletions

diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c
new file mode 100644
index 000000000..6fdad22a5
--- /dev/null
+++ b/drivers/clk/meson/clk-pll.c
@@ -0,0 +1,251 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2015 Endless Mobile, Inc.
+ * Author: Carlo Caione <carlo@endlessm.com>
+ *
+ * Copyright (c) 2018 Baylibre, SAS.
+ * Author: Jerome Brunet <jbrunet@baylibre.com>
+ */
+
+/*
+ * In the most basic form, a Meson PLL is composed as follows:
+ *
+ *                     PLL
+ *      +------------------------------+
+ *      |                              |
+ * in -----[ /N ]---[ *M ]---[ >>OD ]----->> out
+ *      |         ^        ^           |
+ *      +------------------------------+
+ *                |        |
+ *               FREF     VCO
+ *
+ * out = in * (m + frac / frac_max) / (n << sum(ods))
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+#include "clkc.h"
+
+static inline struct meson_clk_pll_data *
+meson_clk_pll_data(struct clk_regmap *clk)
+{
+	return (struct meson_clk_pll_data *)clk->data;
+}
+
+static unsigned long __pll_params_to_rate(unsigned long parent_rate,
+					  const struct pll_rate_table *pllt,
+					  u16 frac,
+					  struct meson_clk_pll_data *pll)
+{
+	u64 rate = (u64)parent_rate * pllt->m;
+	unsigned int od = pllt->od + pllt->od2 + pllt->od3;
+
+	if (frac && MESON_PARM_APPLICABLE(&pll->frac)) {
+		u64 frac_rate = (u64)parent_rate * frac;
+
+		rate += DIV_ROUND_UP_ULL(frac_rate,
+					 (1 << pll->frac.width));
+	}
+
+	return DIV_ROUND_UP_ULL(rate, pllt->n << od);
+}
+
+static unsigned long meson_clk_pll_recalc_rate(struct clk_hw *hw,
+						unsigned long parent_rate)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct meson_clk_pll_data *pll = meson_clk_pll_data(clk);
+	struct pll_rate_table pllt;
+	u16 frac;
+
+	pllt.n = meson_parm_read(clk->map, &pll->n);
+	pllt.m = meson_parm_read(clk->map, &pll->m);
+	pllt.od = meson_parm_read(clk->map, &pll->od);
+
+	pllt.od2 = MESON_PARM_APPLICABLE(&pll->od2) ?
+		meson_parm_read(clk->map, &pll->od2) :
+		0;
+
+	pllt.od3 = MESON_PARM_APPLICABLE(&pll->od3) ?
+		meson_parm_read(clk->map, &pll->od3) :
+		0;
+
+	frac = MESON_PARM_APPLICABLE(&pll->frac) ?
+		meson_parm_read(clk->map, &pll->frac) :
+		0;
+
+	return __pll_params_to_rate(parent_rate, &pllt, frac, pll);
+}
+
+static u16 __pll_params_with_frac(unsigned long rate,
+				  unsigned long parent_rate,
+				  const struct pll_rate_table *pllt,
+				  struct meson_clk_pll_data *pll)
+{
+	u16 frac_max = (1 << pll->frac.width);
+	u64 val = (u64)rate * pllt->n;
+
+	val <<= pllt->od + pllt->od2 + pllt->od3;
+
+	if (pll->flags & CLK_MESON_PLL_ROUND_CLOSEST)
+		val = DIV_ROUND_CLOSEST_ULL(val * frac_max, parent_rate);
+	else
+		val = div_u64(val * frac_max, parent_rate);
+
+	val -= pllt->m * frac_max;
+
+	return min((u16)val, (u16)(frac_max - 1));
+}
+
+static const struct pll_rate_table *
+meson_clk_get_pll_settings(unsigned long rate,
+			   struct meson_clk_pll_data *pll)
+{
+	const struct pll_rate_table *table = pll->table;
+	unsigned int i = 0;
+
+	if (!table)
+		return NULL;
+
+	/* Find the first table element exceeding rate */
+	while (table[i].rate && table[i].rate <= rate)
+		i++;
+
+	if (i != 0) {
+		if (MESON_PARM_APPLICABLE(&pll->frac) ||
+		    !(pll->flags & CLK_MESON_PLL_ROUND_CLOSEST) ||
+		    (abs(rate - table[i - 1].rate) <
+		     abs(rate - table[i].rate)))
+			i--;
+	}
+
+	return (struct pll_rate_table *)&table[i];
+}
+
+static long meson_clk_pll_round_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long *parent_rate)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct meson_clk_pll_data *pll = meson_clk_pll_data(clk);
+	const struct pll_rate_table *pllt =
+		meson_clk_get_pll_settings(rate, pll);
+	u16 frac;
+
+	if (!pllt)
+		return meson_clk_pll_recalc_rate(hw, *parent_rate);
+
+	if (!MESON_PARM_APPLICABLE(&pll->frac)
+	    || rate == pllt->rate)
+		return pllt->rate;
+
+	/*
+	 * The rate provided by the setting is not an exact match, let's
+	 * try to improve the result using the fractional parameter
+	 */
+	frac = __pll_params_with_frac(rate, *parent_rate, pllt, pll);
+
+	return __pll_params_to_rate(*parent_rate, pllt, frac, pll);
+}
+
+static int meson_clk_pll_wait_lock(struct clk_hw *hw)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct meson_clk_pll_data *pll = meson_clk_pll_data(clk);
+	int delay = 24000000;
+
+	do {
+		/* Is the clock locked now ? */
+		if (meson_parm_read(clk->map, &pll->l))
+			return 0;
+
+		delay--;
+	} while (delay > 0);
+
+	return -ETIMEDOUT;
+}
+
+static void meson_clk_pll_init(struct clk_hw *hw)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct meson_clk_pll_data *pll = meson_clk_pll_data(clk);
+
+	if (pll->init_count) {
+		meson_parm_write(clk->map, &pll->rst, 1);
+		regmap_multi_reg_write(clk->map, pll->init_regs,
+				       pll->init_count);
+		meson_parm_write(clk->map, &pll->rst, 0);
+	}
+}
+
+static int meson_clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
+				  unsigned long parent_rate)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct meson_clk_pll_data *pll = meson_clk_pll_data(clk);
+	const struct pll_rate_table *pllt;
+	unsigned long old_rate;
+	u16 frac = 0;
+
+	if (parent_rate == 0 || rate == 0)
+		return -EINVAL;
+
+	old_rate = clk_hw_get_rate(hw);
+
+	pllt = meson_clk_get_pll_settings(rate, pll);
+	if (!pllt)
+		return -EINVAL;
+
+	/* Put the pll in reset to write the params */
+	meson_parm_write(clk->map, &pll->rst, 1);
+
+	meson_parm_write(clk->map, &pll->n, pllt->n);
+	meson_parm_write(clk->map, &pll->m, pllt->m);
+	meson_parm_write(clk->map, &pll->od, pllt->od);
+
+	if (MESON_PARM_APPLICABLE(&pll->od2))
+		meson_parm_write(clk->map, &pll->od2, pllt->od2);
+
+	if (MESON_PARM_APPLICABLE(&pll->od3))
+		meson_parm_write(clk->map, &pll->od3, pllt->od3);
+
+	if (MESON_PARM_APPLICABLE(&pll->frac)) {
+		frac = __pll_params_with_frac(rate, parent_rate, pllt, pll);
+		meson_parm_write(clk->map, &pll->frac, frac);
+	}
+
+	/* make sure the reset is cleared at this point */
+	meson_parm_write(clk->map, &pll->rst, 0);
+
+	if (meson_clk_pll_wait_lock(hw)) {
+		pr_warn("%s: pll did not lock, trying to restore old rate %lu\n",
+			__func__, old_rate);
+		/*
+		 * FIXME: Do we really need/want this HACK ?
+		 * It looks unsafe. what happens if the clock gets into a
+		 * broken state and we can't lock back on the old_rate ? Looks
+		 * like an infinite recursion is possible
+		 */
+		meson_clk_pll_set_rate(hw, old_rate, parent_rate);
+	}
+
+	return 0;
+}
+
+const struct clk_ops meson_clk_pll_ops = {
+	.init		= meson_clk_pll_init,
+	.recalc_rate	= meson_clk_pll_recalc_rate,
+	.round_rate	= meson_clk_pll_round_rate,
+	.set_rate	= meson_clk_pll_set_rate,
+};
+
+const struct clk_ops meson_clk_pll_ro_ops = {
+	.recalc_rate	= meson_clk_pll_recalc_rate,
+};