Messages in this thread | | | Date | Wed, 15 Jan 2014 10:54:45 +0100 | Subject | Re: [PATCH v2 06/12] at91: smc: Adds helper functions to validate and clip the smc timings. | From | Jean-Jacques Hiblot <> |
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2014/1/15 Nicolas Ferre <nicolas.ferre@atmel.com>: > On 09/01/2014 13:31, Jean-Jacques Hiblot : >> 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) > > Don't we have something generic for this? > > Check include/asm-generic/bitops/count_zeros.h
I wonder how I could have missed this one :o)
> >> +{ >> + 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) > > I do not like the use of macro for this. You can convert them to > functions and it would increase readability. I am pretty confident that > gcc will optimize it so that is won't impact performance.
It's not a matter of performance. I wanted to use the stringification for the debug message.
> >> +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) > > Ditto. > >> + >> +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) >> { >> > > > -- > Nicolas Ferre
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