// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <stdint.h>
#include <stdlib.h>
#include <threads.h>
#include <unistd.h>
#include <zircon/assert.h>
#include <zircon/types.h>

#include <bits/limits.h>
#include <ddk/debug.h>
#include <soc/aml-a113/a113-clocks.h>

#define DIV_ROUND_UP(n, d) ((n + d - 1) / d)

/* create instance of a113_clock_t and do basic initialization.
 */
zx_status_t a113_clk_init(a113_clk_dev_t **device) {
  *device = calloc(1, sizeof(a113_clk_dev_t));
  if (!(*device)) {
    return ZX_ERR_NO_MEMORY;
  }

  // Please do not use get_root_resource() in new code. See fxbug.dev/31358.
  zx_handle_t resource = get_root_resource();
  zx_status_t status;

  status = mmio_buffer_init_physical(&(*device)->mmio, A113_CLOCKS_BASE_PHYS, PAGE_SIZE, resource,
                                     ZX_CACHE_POLICY_UNCACHED_DEVICE);

  if (status != ZX_OK) {
    zxlogf(ERROR, "a113_clk_init: mmio_buffer_init_physical failed %d", status);
    goto init_fail;
  }
  (*device)->regs_vaddr = (*device)->mmio.vaddr;

  return ZX_OK;

init_fail:
  mmio_buffer_release(&(*device)->mmio);
  free(*device);
  return status;
}

static void a113_clk_update_reg(a113_clk_dev_t *dev, uint32_t offset, uint32_t pos, uint32_t bits,
                                uint32_t value) {
  uint32_t reg = a113_clk_get_reg(dev, offset);
  reg &= ~(((1 << bits) - 1) << pos);
  reg |= (value & ((1 << bits) - 1)) << pos;
  a113_clk_set_reg(dev, offset, reg);
}

zx_status_t a113_clk_set_mpll2(a113_clk_dev_t *device, uint64_t rate, uint64_t *actual) {
  /* Overall ratio is reference/(n + sdm/16384)
     In this case the 2.0GHz fixed rate pll is the reference
  */
  uint64_t n = A113_FIXED_PLL_RATE / rate;  // calculate the integer ratio;
  ZX_DEBUG_ASSERT(n < (1 << 9));

  uint64_t sdm = DIV_ROUND_UP((A113_FIXED_PLL_RATE - n * rate) * SDM_FRACTIONALITY, rate);
  ZX_DEBUG_ASSERT(sdm < (1 << 14));
  zxlogf(INFO, "%s sdm= %ld  n= %ld", __func__, sdm, n);
  a113_clk_update_reg(device, A113_HHI_MPLL_CNTL8, 0, 14, (uint32_t)sdm);
  a113_clk_update_reg(device, A113_HHI_MPLL_CNTL8, 16, 9, (uint32_t)n);

  // Enable sdm divider
  a113_clk_update_reg(device, A113_HHI_MPLL_CNTL8, 15, 1, 1);
  // Enable mpll2
  a113_clk_update_reg(device, A113_HHI_MPLL_CNTL8, 14, 1, 1);
  // Gate mpll2 through to rest of system
  a113_clk_update_reg(device, A113_HHI_PLL_TOP_MISC, 2, 1, 1);

  if (actual) {
    *actual = ((uint64_t)SDM_FRACTIONALITY * A113_FIXED_PLL_RATE) / ((SDM_FRACTIONALITY * n) + sdm);
  }

  return ZX_OK;
}