101 lines
2.4 KiB
C
101 lines
2.4 KiB
C
/*
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* Copyright 2008-2012 Freescale Semiconductor, Inc.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* Version 2 as published by the Free Software Foundation.
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*/
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#include <common.h>
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#include <asm/fsl_law.h>
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#include <asm-generic/div64.h>
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#include <mach/clock.h>
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#include "ddr.h"
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#define ULL_2E12 2000000000000ULL
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#define UL_5POW12 244140625UL
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#define UL_2POW13 (1UL << 13)
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#define ULL_8FS 0xFFFFFFFFULL
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/*
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* Round up mclk_ps to nearest 1 ps in memory controller code
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* if the error is 0.5ps or more.
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*
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* If an imprecise data rate is too high due to rounding error
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* propagation, compute a suitably rounded mclk_ps to compute
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* a working memory controller configuration.
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*/
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uint32_t get_memory_clk_period_ps(void)
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{
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uint32_t result, data_rate = fsl_get_ddr_freq(0);
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/* Round to nearest 10ps, being careful about 64-bit multiply/divide */
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uint64_t rem, mclk_ps = ULL_2E12;
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/* Now perform the big divide, the result fits in 32-bits */
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rem = do_div(mclk_ps, data_rate);
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if (rem >= (data_rate >> 1))
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result = mclk_ps + 1;
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else
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result = mclk_ps;
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return result;
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}
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/* Convert picoseconds into DRAM clock cycles (rounding up if needed). */
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uint32_t picos_to_mclk(uint32_t picos)
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{
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uint64_t clks, clks_rem;
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uint32_t data_rate = fsl_get_ddr_freq(0);
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if (!picos)
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return 0;
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/* First multiply the time by the data rate (32x32 => 64) */
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clks = picos * (uint64_t)data_rate;
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/*
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* Now divide by 5^12 and track the 32-bit remainder, then divide
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* by 2*(2^12) using shifts (and updating the remainder).
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*/
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clks_rem = do_div(clks, UL_5POW12);
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clks_rem += (clks & (UL_2POW13 - 1)) * UL_5POW12;
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clks >>= 13;
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/* If we had a remainder greater than the 1ps error, then round up */
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if (clks_rem > data_rate)
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clks++;
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if (clks > ULL_8FS)
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clks = ULL_8FS;
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return (uint32_t)clks;
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}
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uint32_t mclk_to_picos(unsigned int mclk)
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{
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return get_memory_clk_period_ps() * mclk;
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}
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int fsl_ddr_set_lawbar(
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const struct common_timing_params_s *params,
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uint32_t law_memctl)
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{
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uint64_t base = params->base_address;
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uint64_t size = params->total_mem;
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if (!params->ndimms_present)
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goto out;
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if (base >= MAX_MEM_MAPPED)
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goto error;
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if ((base + size) >= MAX_MEM_MAPPED)
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size = MAX_MEM_MAPPED - base;
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if (fsl_set_ddr_laws(base, size, law_memctl) < 0)
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goto error;
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out:
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return 0;
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error:
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return 1;
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}
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