Signed-off-by: Jan Luebbe <jlu@xxxxxxxxxxxxxx> --- arch/arm/mach-davinci/Makefile | 1 + arch/arm/mach-davinci/aemif.c | 128 ++++++++++++++++++++++++++++ arch/arm/mach-davinci/include/mach/aemif.h | 36 ++++++++ 3 files changed, 165 insertions(+) create mode 100644 arch/arm/mach-davinci/aemif.c create mode 100644 arch/arm/mach-davinci/include/mach/aemif.h diff --git a/arch/arm/mach-davinci/Makefile b/arch/arm/mach-davinci/Makefile index 0df1e92..2c35ca0 100644 --- a/arch/arm/mach-davinci/Makefile +++ b/arch/arm/mach-davinci/Makefile @@ -1,3 +1,4 @@ +obj-y += aemif.o obj-y += clock.o obj-y += clocksource.o obj-y += da850.o diff --git a/arch/arm/mach-davinci/aemif.c b/arch/arm/mach-davinci/aemif.c new file mode 100644 index 0000000..1468899 --- /dev/null +++ b/arch/arm/mach-davinci/aemif.c @@ -0,0 +1,128 @@ +/* + * AEMIF support for DaVinci SoCs + * + * Copyright (C) 2010 Texas Instruments Incorporated. http://www.ti.com/ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <common.h> +#include <errno.h> +#include <io.h> + +#include <mach/hardware.h> +#include <mach/aemif.h> + +#define NSEC_PER_MSEC (1000*1000) + +/* Timing value configuration */ + +#define TA(x) ((x) << 2) +#define RHOLD(x) ((x) << 4) +#define RSTROBE(x) ((x) << 7) +#define RSETUP(x) ((x) << 13) +#define WHOLD(x) ((x) << 17) +#define WSTROBE(x) ((x) << 20) +#define WSETUP(x) ((x) << 26) + +#define TA_MAX 0x3 +#define RHOLD_MAX 0x7 +#define RSTROBE_MAX 0x3f +#define RSETUP_MAX 0xf +#define WHOLD_MAX 0x7 +#define WSTROBE_MAX 0x3f +#define WSETUP_MAX 0xf + +#define TIMING_MASK (TA(TA_MAX) | \ + RHOLD(RHOLD_MAX) | \ + RSTROBE(RSTROBE_MAX) | \ + RSETUP(RSETUP_MAX) | \ + WHOLD(WHOLD_MAX) | \ + WSTROBE(WSTROBE_MAX) | \ + WSETUP(WSETUP_MAX)) + +/* + * aemif_calc_rate - calculate timing data. + * @wanted: The cycle time needed in nanoseconds. + * @clk: The input clock rate in kHz. + * @max: The maximum divider value that can be programmed. + * + * On success, returns the calculated timing value minus 1 for easy + * programming into AEMIF timing registers, else negative errno. + */ +static int aemif_calc_rate(int wanted, unsigned long clk, int max) +{ + int result; + + result = DIV_ROUND_UP((wanted * clk), NSEC_PER_MSEC) - 1; + + pr_debug("%s: result %d from %ld, %d\n", __func__, result, clk, wanted); + + /* It is generally OK to have a more relaxed timing than requested... */ + if (result < 0) + result = 0; + + /* ... But configuring tighter timings is not an option. */ + else if (result > max) + result = -EINVAL; + + return result; +} + +/** + * davinci_aemif_setup_timing - setup timing values for a given AEMIF interface + * @t: timing values to be progammed + * @base: The virtual base address of the AEMIF interface + * @cs: chip-select to program the timing values for + * + * This function programs the given timing values (in real clock) into the + * AEMIF registers taking the AEMIF clock into account. + * + * This function does not use any locking while programming the AEMIF + * because it is expected that there is only one user of a given + * chip-select. + * + * Returns 0 on success, else negative errno. + */ +int davinci_aemif_setup_timing(struct davinci_aemif_timing *t, + void __iomem *base, unsigned cs) +{ + unsigned set, val; + int ta, rhold, rstrobe, rsetup, whold, wstrobe, wsetup; + unsigned offset = A1CR_OFFSET + cs * 4; + unsigned long clkrate; + + if (!t) + return 0; /* Nothing to do */ + + clkrate = da8xx_clk_get(DAVINCI_EMIFA_CLKID); + + clkrate /= 1000; /* turn clock into kHz for ease of use */ + + ta = aemif_calc_rate(t->ta, clkrate, TA_MAX); + rhold = aemif_calc_rate(t->rhold, clkrate, RHOLD_MAX); + rstrobe = aemif_calc_rate(t->rstrobe, clkrate, RSTROBE_MAX); + rsetup = aemif_calc_rate(t->rsetup, clkrate, RSETUP_MAX); + whold = aemif_calc_rate(t->whold, clkrate, WHOLD_MAX); + wstrobe = aemif_calc_rate(t->wstrobe, clkrate, WSTROBE_MAX); + wsetup = aemif_calc_rate(t->wsetup, clkrate, WSETUP_MAX); + + if (ta < 0 || rhold < 0 || rstrobe < 0 || rsetup < 0 || + whold < 0 || wstrobe < 0 || wsetup < 0) { + pr_err("%s: cannot get suitable timings\n", __func__); + return -EINVAL; + } + + set = TA(ta) | RHOLD(rhold) | RSTROBE(rstrobe) | RSETUP(rsetup) | + WHOLD(whold) | WSTROBE(wstrobe) | WSETUP(wsetup); + + val = readl(base + offset); + val &= ~TIMING_MASK; + val |= set; + writel(val, base + offset); + + return 0; +} +EXPORT_SYMBOL(davinci_aemif_setup_timing); diff --git a/arch/arm/mach-davinci/include/mach/aemif.h b/arch/arm/mach-davinci/include/mach/aemif.h new file mode 100644 index 0000000..05b2934 --- /dev/null +++ b/arch/arm/mach-davinci/include/mach/aemif.h @@ -0,0 +1,36 @@ +/* + * TI DaVinci AEMIF support + * + * Copyright 2010 (C) Texas Instruments, Inc. http://www.ti.com/ + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ +#ifndef _MACH_DAVINCI_AEMIF_H +#define _MACH_DAVINCI_AEMIF_H + +#define NRCSR_OFFSET 0x00 +#define AWCCR_OFFSET 0x04 +#define A1CR_OFFSET 0x10 + +#define ACR_ASIZE_MASK 0x3 +#define ACR_EW_MASK BIT(30) +#define ACR_SS_MASK BIT(31) + +/* All timings in nanoseconds */ +struct davinci_aemif_timing { + u8 wsetup; + u8 wstrobe; + u8 whold; + + u8 rsetup; + u8 rstrobe; + u8 rhold; + + u8 ta; +}; + +int davinci_aemif_setup_timing(struct davinci_aemif_timing *t, + void __iomem *base, unsigned cs); +#endif -- 1.7.10 _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
