Quelle  ccu_pll.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2024 SpacemiT Technology Co. Ltd
 * Copyright (c) 2024-2025 Haylen Chu <heylenay@4d2.org>
 */

#include <linux/clk-provider.h>
#include <linux/math.h>
#include <linux/regmap.h>

#include "ccu_common.h"
#include "ccu_pll.h"

#define PLL_TIMEOUT_US  3000
#define PLL_DELAY_US  5

#define PLL_SWCR3_EN  ((u32)BIT(31))
#define PLL_SWCR3_MASK  GENMASK(30, 0)

static const struct ccu_pll_rate_tbl *ccu_pll_lookup_best_rate(struct ccu_pll *pll,
              unsigned long rate)
{
 struct ccu_pll_config *config = &pll->config;
 const struct ccu_pll_rate_tbl *best_entry;
 unsigned long best_delta = ULONG_MAX;
 int i;

 for (i = 0; i < config->tbl_num; i++) {
  const struct ccu_pll_rate_tbl *entry = &config->rate_tbl[i];
  unsigned long delta = abs_diff(entry->rate, rate);

  if (delta < best_delta) {
   best_delta = delta;
   best_entry = entry;
  }
 }

 return best_entry;
}

static const struct ccu_pll_rate_tbl *ccu_pll_lookup_matched_entry(struct ccu_pll *pll)
{
 struct ccu_pll_config *config = &pll->config;
 u32 swcr1, swcr3;
 int i;

 swcr1 = ccu_read(&pll->common, swcr1);
 swcr3 = ccu_read(&pll->common, swcr3);
 swcr3 &= PLL_SWCR3_MASK;

 for (i = 0; i < config->tbl_num; i++) {
  const struct ccu_pll_rate_tbl *entry = &config->rate_tbl[i];

  if (swcr1 == entry->swcr1 && swcr3 == entry->swcr3)
   return entry;
 }

 return NULL;
}

static void ccu_pll_update_param(struct ccu_pll *pll, const struct ccu_pll_rate_tbl *entry)
{
 struct ccu_common *common = &pll->common;

 regmap_write(common->regmap, common->reg_swcr1, entry->swcr1);
 ccu_update(common, swcr3, PLL_SWCR3_MASK, entry->swcr3);
}

static int ccu_pll_is_enabled(struct clk_hw *hw)
{
 struct ccu_common *common = hw_to_ccu_common(hw);

 return ccu_read(common, swcr3) & PLL_SWCR3_EN;
}

static int ccu_pll_enable(struct clk_hw *hw)
{
 struct ccu_pll *pll = hw_to_ccu_pll(hw);
 struct ccu_common *common = &pll->common;
 unsigned int tmp;

 ccu_update(common, swcr3, PLL_SWCR3_EN, PLL_SWCR3_EN);

 /* check lock status */
 return regmap_read_poll_timeout_atomic(common->lock_regmap,
            pll->config.reg_lock,
            tmp,
            tmp & pll->config.mask_lock,
            PLL_DELAY_US, PLL_TIMEOUT_US);
}

static void ccu_pll_disable(struct clk_hw *hw)
{
 struct ccu_common *common = hw_to_ccu_common(hw);

 ccu_update(common, swcr3, PLL_SWCR3_EN, 0);
}

/*
 * PLLs must be gated before changing rate, which is ensured by
 * flag CLK_SET_RATE_GATE.
 */
static int ccu_pll_set_rate(struct clk_hw *hw, unsigned long rate,
       unsigned long parent_rate)
{
 struct ccu_pll *pll = hw_to_ccu_pll(hw);
 const struct ccu_pll_rate_tbl *entry;

 entry = ccu_pll_lookup_best_rate(pll, rate);
 ccu_pll_update_param(pll, entry);

 return 0;
}

static unsigned long ccu_pll_recalc_rate(struct clk_hw *hw,
      unsigned long parent_rate)
{
 struct ccu_pll *pll = hw_to_ccu_pll(hw);
 const struct ccu_pll_rate_tbl *entry;

 entry = ccu_pll_lookup_matched_entry(pll);

 WARN_ON_ONCE(!entry);

 return entry ? entry->rate : 0;
}

static long ccu_pll_round_rate(struct clk_hw *hw, unsigned long rate,
          unsigned long *prate)
{
 struct ccu_pll *pll = hw_to_ccu_pll(hw);

 return ccu_pll_lookup_best_rate(pll, rate)->rate;
}

static int ccu_pll_init(struct clk_hw *hw)
{
 struct ccu_pll *pll = hw_to_ccu_pll(hw);

 if (ccu_pll_lookup_matched_entry(pll))
  return 0;

 ccu_pll_disable(hw);
 ccu_pll_update_param(pll, &pll->config.rate_tbl[0]);

 return 0;
}

const struct clk_ops spacemit_ccu_pll_ops = {
 .init  = ccu_pll_init,
 .enable  = ccu_pll_enable,
 .disable = ccu_pll_disable,
 .set_rate = ccu_pll_set_rate,
 .recalc_rate = ccu_pll_recalc_rate,
 .round_rate = ccu_pll_round_rate,
 .is_enabled = ccu_pll_is_enabled,
};