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Diffstat (limited to 'cpu/at32ap/hsdramc.c')
| -rw-r--r-- | cpu/at32ap/hsdramc.c | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/cpu/at32ap/hsdramc.c b/cpu/at32ap/hsdramc.c new file mode 100644 index 0000000..f36da35 --- /dev/null +++ b/cpu/at32ap/hsdramc.c @@ -0,0 +1,155 @@ +/* + * Copyright (C) 2005-2006 Atmel Corporation + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ +#include <common.h> + +#ifdef CFG_HSDRAMC +#include <asm/io.h> +#include <asm/sdram.h> + +#include <asm/arch/platform.h> + +#include "hsdramc1.h" + +struct hsdramc { + const struct device *hebi; + void *regs; +}; + +static struct hsdramc hsdramc; + +unsigned long sdram_init(const struct sdram_info *info) +{ + unsigned long *sdram = (unsigned long *)uncached(info->phys_addr); + unsigned long sdram_size; + unsigned long tmp; + unsigned long bus_hz; + unsigned int i; + + hsdramc.hebi = get_device(DEVICE_HEBI); + if (!hsdramc.hebi) + return 0; + + /* FIXME: Both of these lines are complete hacks */ + hsdramc.regs = hsdramc.hebi->regs + 0x400; + bus_hz = pm_get_clock_freq(hsdramc.hebi->resource[0].u.clock.id); + + cpu_enable_sdram(); + + tmp = (HSDRAMC1_BF(NC, info->col_bits - 8) + | HSDRAMC1_BF(NR, info->row_bits - 11) + | HSDRAMC1_BF(NB, info->bank_bits - 1) + | HSDRAMC1_BF(CAS, info->cas) + | HSDRAMC1_BF(TWR, info->twr) + | HSDRAMC1_BF(TRC, info->trc) + | HSDRAMC1_BF(TRP, info->trp) + | HSDRAMC1_BF(TRCD, info->trcd) + | HSDRAMC1_BF(TRAS, info->tras) + | HSDRAMC1_BF(TXSR, info->txsr)); + +#ifdef CFG_SDRAM_16BIT + tmp |= HSDRAMC1_BIT(DBW); + sdram_size = 1 << (info->row_bits + info->col_bits + + info->bank_bits + 1); +#else + sdram_size = 1 << (info->row_bits + info->col_bits + + info->bank_bits + 2); +#endif + + hsdramc1_writel(&hsdramc, CR, tmp); + + /* + * Initialization sequence for SDRAM, from the data sheet: + * + * 1. A minimum pause of 200 us is provided to precede any + * signal toggle. + */ + udelay(200); + + /* + * 2. A Precharge All command is issued to the SDRAM + */ + hsdramc1_writel(&hsdramc, MR, HSDRAMC1_MODE_BANKS_PRECHARGE); + hsdramc1_readl(&hsdramc, MR); + writel(0, sdram); + + /* + * 3. Eight auto-refresh (CBR) cycles are provided + */ + hsdramc1_writel(&hsdramc, MR, HSDRAMC1_MODE_AUTO_REFRESH); + hsdramc1_readl(&hsdramc, MR); + for (i = 0; i < 8; i++) + writel(0, sdram); + + /* + * 4. A mode register set (MRS) cycle is issued to program + * SDRAM parameters, in particular CAS latency and burst + * length. + * + * CAS from info struct, burst length 1, serial burst type + */ + hsdramc1_writel(&hsdramc, MR, HSDRAMC1_MODE_LOAD_MODE); + hsdramc1_readl(&hsdramc, MR); + writel(0, sdram + (info->cas << 4)); + + /* + * 5. A Normal Mode command is provided, 3 clocks after tMRD + * is met. + * + * From the timing diagram, it looks like tMRD is 3 + * cycles...try a dummy read from the peripheral bus. + */ + hsdramc1_readl(&hsdramc, MR); + hsdramc1_writel(&hsdramc, MR, HSDRAMC1_MODE_NORMAL); + hsdramc1_readl(&hsdramc, MR); + writel(0, sdram); + + /* + * 6. Write refresh rate into SDRAMC refresh timer count + * register (refresh rate = timing between refresh cycles). + * + * 15.6 us is a typical value for a burst of length one + */ + hsdramc1_writel(&hsdramc, TR, (156 * (bus_hz / 1000)) / 10000); + + printf("SDRAM: %u MB at address 0x%08lx\n", + sdram_size >> 20, info->phys_addr); + + printf("Testing SDRAM..."); + for (i = 0; i < sdram_size / 4; i++) + sdram[i] = i; + + for (i = 0; i < sdram_size / 4; i++) { + tmp = sdram[i]; + if (tmp != i) { + printf("FAILED at address 0x%08lx\n", + info->phys_addr + i * 4); + printf("SDRAM: read 0x%lx, expected 0x%lx\n", tmp, i); + return 0; + } + } + + puts("OK\n"); + + return sdram_size; +} + +#endif /* CFG_HSDRAMC */ |