0d4f97e270
This patch moves ARM core and DRAM timing functions around to simplify
the dependencies for system_clock_init().
The original code was architected such that the system_clock_init()
function called other functions to obtain core and memory timings.
Due to the way memory timing information must be obtained on Snow,
which entails decoding platform-specific board straps, the bottom-
up approach resulted in having the low-level clock init code
implicitly depend on board and vendor-specific info:
main()
->system_clock_init()
-> get_arm_ratios()
-> CPU-specific code
-> clock_get_mem_timings()
-> board_get_revision()
-> read GPIOs (3-state logic)
-> Decode GPIOs in a vendor-specific manner
-> Choose memory timings from module-specific look-up table
...then proceed to init clocks
...come back to main()
The new approach gathers all board and vendor-specific info in a
more appropriate location and passes it into system_clock_init():
main()
-> get_arm_ratios()
-> CPU-specific code
-> get_mem_timings()
-> board_get_config()
-> read GPIOs (3-state logic)
-> Decode GPIOs in a vendor-specific manner
-> Choose memory timings from module-specific look-up table
-> system_clock_init()
...back to main()
Change-Id: Ie237ebff76fc2d8a4d2f4577a226ac3909e4d4e8
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/2271
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
60 lines
1.7 KiB
C
60 lines
1.7 KiB
C
/*
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* Clock initialization routines
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*
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* Copyright (c) 2011 The Chromium OS Authors.
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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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 as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#ifndef __EXYNOS_CLOCK_INIT_H
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#define __EXYNOS_CLOCK_INIT_H
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/* These are the ratio's for configuring ARM clock */
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struct arm_clk_ratios {
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unsigned int arm_freq_mhz; /* Frequency of ARM core in MHz */
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unsigned int apll_mdiv;
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unsigned int apll_pdiv;
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unsigned int apll_sdiv;
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unsigned int arm2_ratio;
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unsigned int apll_ratio;
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unsigned int pclk_dbg_ratio;
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unsigned int atb_ratio;
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unsigned int periph_ratio;
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unsigned int acp_ratio;
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unsigned int cpud_ratio;
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unsigned int arm_ratio;
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};
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/**
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* Get the clock ratios for CPU configuration
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*
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* @return pointer to the clock ratios that we should use
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*/
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struct arm_clk_ratios *get_arm_clk_ratios(void);
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/*
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* Initialize clock for the device
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*/
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struct mem_timings;
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void system_clock_init(struct mem_timings *mem,
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struct arm_clk_ratios *arm_clk_ratio);
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#endif
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