From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- drivers/clk/meson/clk-pll.c | 453 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 453 insertions(+) create mode 100644 drivers/clk/meson/clk-pll.c (limited to 'drivers/clk/meson/clk-pll.c') diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c new file mode 100644 index 000000000..9e55617bc --- /dev/null +++ b/drivers/clk/meson/clk-pll.c @@ -0,0 +1,453 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2015 Endless Mobile, Inc. + * Author: Carlo Caione + * + * Copyright (c) 2018 Baylibre, SAS. + * Author: Jerome Brunet + */ + +/* + * In the most basic form, a Meson PLL is composed as follows: + * + * PLL + * +--------------------------------+ + * | | + * | +--+ | + * in >>-----[ /N ]--->| | +-----+ | + * | | |------| DCO |---->> out + * | +--------->| | +--v--+ | + * | | +--+ | | + * | | | | + * | +--[ *(M + (F/Fmax) ]<--+ | + * | | + * +--------------------------------+ + * + * out = in * (m + frac / frac_max) / n + */ + +#include +#include +#include +#include +#include +#include +#include + +#include "clk-regmap.h" +#include "clk-pll.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 int __pll_round_closest_mult(struct meson_clk_pll_data *pll) +{ + if ((pll->flags & CLK_MESON_PLL_ROUND_CLOSEST) && + !MESON_PARM_APPLICABLE(&pll->frac)) + return 1; + + return 0; +} + +static unsigned long __pll_params_to_rate(unsigned long parent_rate, + unsigned int m, unsigned int n, + unsigned int frac, + struct meson_clk_pll_data *pll) +{ + u64 rate = (u64)parent_rate * m; + + 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, n); +} + +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); + unsigned int m, n, frac; + + n = meson_parm_read(clk->map, &pll->n); + + /* + * On some HW, N is set to zero on init. This value is invalid as + * it would result in a division by zero. The rate can't be + * calculated in this case + */ + if (n == 0) + return 0; + + m = meson_parm_read(clk->map, &pll->m); + + frac = MESON_PARM_APPLICABLE(&pll->frac) ? + meson_parm_read(clk->map, &pll->frac) : + 0; + + return __pll_params_to_rate(parent_rate, m, n, frac, pll); +} + +static unsigned int __pll_params_with_frac(unsigned long rate, + unsigned long parent_rate, + unsigned int m, + unsigned int n, + struct meson_clk_pll_data *pll) +{ + unsigned int frac_max = (1 << pll->frac.width); + u64 val = (u64)rate * n; + + /* Bail out if we are already over the requested rate */ + if (rate < parent_rate * m / n) + return 0; + + 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 -= m * frac_max; + + return min((unsigned int)val, (frac_max - 1)); +} + +static bool meson_clk_pll_is_better(unsigned long rate, + unsigned long best, + unsigned long now, + struct meson_clk_pll_data *pll) +{ + if (__pll_round_closest_mult(pll)) { + /* Round Closest */ + if (abs(now - rate) < abs(best - rate)) + return true; + } else { + /* Round down */ + if (now <= rate && best < now) + return true; + } + + return false; +} + +static int meson_clk_get_pll_table_index(unsigned int index, + unsigned int *m, + unsigned int *n, + struct meson_clk_pll_data *pll) +{ + if (!pll->table[index].n) + return -EINVAL; + + *m = pll->table[index].m; + *n = pll->table[index].n; + + return 0; +} + +static unsigned int meson_clk_get_pll_range_m(unsigned long rate, + unsigned long parent_rate, + unsigned int n, + struct meson_clk_pll_data *pll) +{ + u64 val = (u64)rate * n; + + if (__pll_round_closest_mult(pll)) + return DIV_ROUND_CLOSEST_ULL(val, parent_rate); + + return div_u64(val, parent_rate); +} + +static int meson_clk_get_pll_range_index(unsigned long rate, + unsigned long parent_rate, + unsigned int index, + unsigned int *m, + unsigned int *n, + struct meson_clk_pll_data *pll) +{ + *n = index + 1; + + /* Check the predivider range */ + if (*n >= (1 << pll->n.width)) + return -EINVAL; + + if (*n == 1) { + /* Get the boundaries out the way */ + if (rate <= pll->range->min * parent_rate) { + *m = pll->range->min; + return -ENODATA; + } else if (rate >= pll->range->max * parent_rate) { + *m = pll->range->max; + return -ENODATA; + } + } + + *m = meson_clk_get_pll_range_m(rate, parent_rate, *n, pll); + + /* the pre-divider gives a multiplier too big - stop */ + if (*m >= (1 << pll->m.width)) + return -EINVAL; + + return 0; +} + +static int meson_clk_get_pll_get_index(unsigned long rate, + unsigned long parent_rate, + unsigned int index, + unsigned int *m, + unsigned int *n, + struct meson_clk_pll_data *pll) +{ + if (pll->range) + return meson_clk_get_pll_range_index(rate, parent_rate, + index, m, n, pll); + else if (pll->table) + return meson_clk_get_pll_table_index(index, m, n, pll); + + return -EINVAL; +} + +static int meson_clk_get_pll_settings(unsigned long rate, + unsigned long parent_rate, + unsigned int *best_m, + unsigned int *best_n, + struct meson_clk_pll_data *pll) +{ + unsigned long best = 0, now = 0; + unsigned int i, m, n; + int ret; + + for (i = 0, ret = 0; !ret; i++) { + ret = meson_clk_get_pll_get_index(rate, parent_rate, + i, &m, &n, pll); + if (ret == -EINVAL) + break; + + now = __pll_params_to_rate(parent_rate, m, n, 0, pll); + if (meson_clk_pll_is_better(rate, best, now, pll)) { + best = now; + *best_m = m; + *best_n = n; + + if (now == rate) + break; + } + } + + return best ? 0 : -EINVAL; +} + +static int meson_clk_pll_determine_rate(struct clk_hw *hw, + struct clk_rate_request *req) +{ + struct clk_regmap *clk = to_clk_regmap(hw); + struct meson_clk_pll_data *pll = meson_clk_pll_data(clk); + unsigned int m, n, frac; + unsigned long round; + int ret; + + ret = meson_clk_get_pll_settings(req->rate, req->best_parent_rate, + &m, &n, pll); + if (ret) + return ret; + + round = __pll_params_to_rate(req->best_parent_rate, m, n, 0, pll); + + if (!MESON_PARM_APPLICABLE(&pll->frac) || req->rate == round) { + req->rate = round; + return 0; + } + + /* + * 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(req->rate, req->best_parent_rate, m, n, pll); + req->rate = __pll_params_to_rate(req->best_parent_rate, m, n, frac, pll); + + return 0; +} + +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 int 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); + } + + return 0; +} + +static int meson_clk_pll_is_enabled(struct clk_hw *hw) +{ + struct clk_regmap *clk = to_clk_regmap(hw); + struct meson_clk_pll_data *pll = meson_clk_pll_data(clk); + + if (meson_parm_read(clk->map, &pll->rst) || + !meson_parm_read(clk->map, &pll->en) || + !meson_parm_read(clk->map, &pll->l)) + return 0; + + return 1; +} + +static int meson_clk_pcie_pll_enable(struct clk_hw *hw) +{ + meson_clk_pll_init(hw); + + if (meson_clk_pll_wait_lock(hw)) + return -EIO; + + return 0; +} + +static int meson_clk_pll_enable(struct clk_hw *hw) +{ + struct clk_regmap *clk = to_clk_regmap(hw); + struct meson_clk_pll_data *pll = meson_clk_pll_data(clk); + + /* do nothing if the PLL is already enabled */ + if (clk_hw_is_enabled(hw)) + return 0; + + /* Make sure the pll is in reset */ + meson_parm_write(clk->map, &pll->rst, 1); + + /* Enable the pll */ + meson_parm_write(clk->map, &pll->en, 1); + + /* Take the pll out reset */ + meson_parm_write(clk->map, &pll->rst, 0); + + if (meson_clk_pll_wait_lock(hw)) + return -EIO; + + return 0; +} + +static void meson_clk_pll_disable(struct clk_hw *hw) +{ + struct clk_regmap *clk = to_clk_regmap(hw); + struct meson_clk_pll_data *pll = meson_clk_pll_data(clk); + + /* Put the pll is in reset */ + meson_parm_write(clk->map, &pll->rst, 1); + + /* Disable the pll */ + meson_parm_write(clk->map, &pll->en, 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); + unsigned int enabled, m, n, frac = 0; + unsigned long old_rate; + int ret; + + if (parent_rate == 0 || rate == 0) + return -EINVAL; + + old_rate = clk_hw_get_rate(hw); + + ret = meson_clk_get_pll_settings(rate, parent_rate, &m, &n, pll); + if (ret) + return ret; + + enabled = meson_parm_read(clk->map, &pll->en); + if (enabled) + meson_clk_pll_disable(hw); + + meson_parm_write(clk->map, &pll->n, n); + meson_parm_write(clk->map, &pll->m, m); + + if (MESON_PARM_APPLICABLE(&pll->frac)) { + frac = __pll_params_with_frac(rate, parent_rate, m, n, pll); + meson_parm_write(clk->map, &pll->frac, frac); + } + + /* If the pll is stopped, bail out now */ + if (!enabled) + return 0; + + ret = meson_clk_pll_enable(hw); + if (ret) { + 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 ret; +} + +/* + * The Meson G12A PCIE PLL is fined tuned to deliver a very precise + * 100MHz reference clock for the PCIe Analog PHY, and thus requires + * a strict register sequence to enable the PLL. + * To simplify, re-use the _init() op to enable the PLL and keep + * the other ops except set_rate since the rate is fixed. + */ +const struct clk_ops meson_clk_pcie_pll_ops = { + .recalc_rate = meson_clk_pll_recalc_rate, + .determine_rate = meson_clk_pll_determine_rate, + .is_enabled = meson_clk_pll_is_enabled, + .enable = meson_clk_pcie_pll_enable, + .disable = meson_clk_pll_disable +}; +EXPORT_SYMBOL_GPL(meson_clk_pcie_pll_ops); + +const struct clk_ops meson_clk_pll_ops = { + .init = meson_clk_pll_init, + .recalc_rate = meson_clk_pll_recalc_rate, + .determine_rate = meson_clk_pll_determine_rate, + .set_rate = meson_clk_pll_set_rate, + .is_enabled = meson_clk_pll_is_enabled, + .enable = meson_clk_pll_enable, + .disable = meson_clk_pll_disable +}; +EXPORT_SYMBOL_GPL(meson_clk_pll_ops); + +const struct clk_ops meson_clk_pll_ro_ops = { + .recalc_rate = meson_clk_pll_recalc_rate, + .is_enabled = meson_clk_pll_is_enabled, +}; +EXPORT_SYMBOL_GPL(meson_clk_pll_ro_ops); + +MODULE_DESCRIPTION("Amlogic PLL driver"); +MODULE_AUTHOR("Carlo Caione "); +MODULE_AUTHOR("Jerome Brunet "); +MODULE_LICENSE("GPL v2"); -- cgit v1.2.3