// 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 <threads.h>
#include <unistd.h>


#include <bits/limits.h>
#include <ddk/debug.h>
#include <hw/reg.h>

#include <zircon/assert.h>
#include <zircon/types.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(zx_handle_t bti, a113_clk_dev_t **device) {

    *device = calloc(1, sizeof(a113_clk_dev_t));
    if (!(*device)) {
        return ZX_ERR_NO_MEMORY;
    }

    zx_handle_t resource = get_root_resource();
    zx_status_t status;

    status = io_buffer_init_physical(&(*device)->regs_iobuff, bti, A113_CLOCKS_BASE_PHYS,PAGE_SIZE,
                                     resource, ZX_CACHE_POLICY_UNCACHED_DEVICE);

    if (status != ZX_OK) {
        zxlogf(ERROR, "a113_clk_init: io_buffer_init_physical failed %d\n", status);
        goto init_fail;
    }

    (*device)->virt_regs = (zx_vaddr_t)(io_buffer_virt(&(*device)->regs_iobuff));

    return ZX_OK;

init_fail:
    if (*device) {
        io_buffer_release(&(*device)->regs_iobuff);
        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\n",__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;
}