Messages in this thread Patch in this message | | | From | Jean-Jacques Hiblot <> | Subject | [PATCH v2 06/12] at91: smc: Adds helper functions to validate and clip the smc timings. | Date | Thu, 9 Jan 2014 13:31:43 +0100 |
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This patchs implememnts 2 functions to help with the configuration of a chip-select's timing: * sam9_smc_check_cs_configuration : checks that the values would fit in the registers. * sam9_smc_clip_cs_configuration : clip the values to their maximum.
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com> --- arch/arm/mach-at91/include/mach/at91sam9_smc.h | 2 + arch/arm/mach-at91/sam9_smc.c | 77 ++++++++++++++++++++++++++ 2 files changed, 79 insertions(+)
diff --git a/arch/arm/mach-at91/include/mach/at91sam9_smc.h b/arch/arm/mach-at91/include/mach/at91sam9_smc.h index c3e29311..615ac56 100644 --- a/arch/arm/mach-at91/include/mach/at91sam9_smc.h +++ b/arch/arm/mach-at91/include/mach/at91sam9_smc.h @@ -47,6 +47,8 @@ extern void sam9_smc_read_mode(int id, int cs, struct sam9_smc_config *config); extern void sam9_smc_write_mode(int id, int cs, struct sam9_smc_config *config); extern void sam9_smc_cs_read(void __iomem *, struct sam9_smc_config *config); extern void sam9_smc_cs_configure(void __iomem *, struct sam9_smc_config *cfg); +extern int sam9_smc_check_cs_configuration(struct sam9_smc_config *config); +extern void sam9_smc_clip_cs_configuration(struct sam9_smc_config *config); #endif #define AT91_SMC_SETUP 0x00 /* Setup Register for CS n */ diff --git a/arch/arm/mach-at91/sam9_smc.c b/arch/arm/mach-at91/sam9_smc.c index d7a6156..fe3c492 100644 --- a/arch/arm/mach-at91/sam9_smc.c +++ b/arch/arm/mach-at91/sam9_smc.c @@ -23,6 +23,83 @@ static void __iomem *smc_base_addr[2]; +static int count_trailing_zeroes(u32 x) +{ + int ret = 0; + if (!(x & 0xFFFF)) { + ret += 16; + x = x >> 16; + } + if (!(x & 0xFF)) { + ret += 8; + x = x >> 8; + } + if (!(x & 0xF)) { + ret += 4; + x = x >> 4; + } + if (!(x & 0x3)) { + ret += 2; + x = x >> 2; + } + if (!(x & 0x1)) { + ret += 1; + x = x >> 1; + } + if (!(x & 0x1)) + ret += 1; + + return ret; +} + + +#define __CHECK_CFG(config, x, y) do {\ + if (x##_(config->y) > x) {\ + pr_debug("error: %s (0x%x) is out of range\n", #y,\ + config->y >> count_trailing_zeroes(x));\ + return -EINVAL;\ + } \ + } while (0) + +int sam9_smc_check_cs_configuration(struct sam9_smc_config *config) +{ + __CHECK_CFG(config, AT91_SMC_NWESETUP, nwe_setup); + __CHECK_CFG(config, AT91_SMC_NCS_WRSETUP, ncs_write_setup); + __CHECK_CFG(config, AT91_SMC_NRDSETUP, nrd_setup); + __CHECK_CFG(config, AT91_SMC_NCS_RDSETUP, ncs_read_setup); + __CHECK_CFG(config, AT91_SMC_NWEPULSE, nwe_pulse); + __CHECK_CFG(config, AT91_SMC_NCS_WRPULSE, ncs_write_pulse); + __CHECK_CFG(config, AT91_SMC_NRDPULSE, nrd_pulse); + __CHECK_CFG(config, AT91_SMC_NCS_RDPULSE, ncs_read_pulse); + __CHECK_CFG(config, AT91_SMC_NWECYCLE, write_cycle); + __CHECK_CFG(config, AT91_SMC_NRDCYCLE, read_cycle); + __CHECK_CFG(config, AT91_SMC_TDF, tdf_cycles); + return 0; +} + +#define __CLIP_CFG(config, x, y) do {\ + if (x##_(config->y) > x) {\ + config->y = x >> count_trailing_zeroes(x);\ + pr_debug("clipping %s to %d\n", #y, config->y);\ + } \ + } while (0) + +void sam9_smc_clip_cs_configuration(struct sam9_smc_config *config) +{ + __CLIP_CFG(config, AT91_SMC_NWESETUP, nwe_setup); + __CLIP_CFG(config, AT91_SMC_NCS_WRSETUP, ncs_write_setup); + __CLIP_CFG(config, AT91_SMC_NRDSETUP, nrd_setup); + __CLIP_CFG(config, AT91_SMC_NCS_RDSETUP, ncs_read_setup); + __CLIP_CFG(config, AT91_SMC_NWEPULSE, nwe_pulse); + __CLIP_CFG(config, AT91_SMC_NCS_WRPULSE, ncs_write_pulse); + __CLIP_CFG(config, AT91_SMC_NRDPULSE, nrd_pulse); + __CLIP_CFG(config, AT91_SMC_NCS_RDPULSE, ncs_read_pulse); + __CLIP_CFG(config, AT91_SMC_NWECYCLE, write_cycle); + __CLIP_CFG(config, AT91_SMC_NRDCYCLE, read_cycle); + __CLIP_CFG(config, AT91_SMC_TDF, tdf_cycles); + +} + static void sam9_smc_cs_write_mode(void __iomem *base, struct sam9_smc_config *config) { -- 1.8.5.2
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