Re: [PATCH 1/7] mfd: syscon: atmel-smc: Add new helpers to ease SMC regs manipulation

[Lee Jones]

On Mon, 20 Feb 2017, Boris Brezillon wrote:

> These new helpers + macro definitions are meant to replace the old ones
> which are unpractical to use.
> 
> Note that the macros and function prefixes have been intentionally
> changed to ATMEL_[H]SMC_XX and atmel_[h]smc_ to reflect the fact that
> this IP is also embedded in avr32 SoCs (and not only in at91 ones).

I'm going to NACK this patch.

I don't see any reason why all those functions have to be inline and
shoved into a header file.

> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
> ---
>  include/linux/mfd/syscon/atmel-smc.h | 362 +++++++++++++++++++++++++++++++++++
>  1 file changed, 362 insertions(+)
> 
> diff --git a/include/linux/mfd/syscon/atmel-smc.h b/include/linux/mfd/syscon/atmel-smc.h
> index be6ebe64eebe..6124f3d2b965 100644
> --- a/include/linux/mfd/syscon/atmel-smc.h
> +++ b/include/linux/mfd/syscon/atmel-smc.h
> @@ -69,6 +69,368 @@
>  #define AT91_SMC_PS_16			(2 << 28)
>  #define AT91_SMC_PS_32			(3 << 28)
>  
> +#define ATMEL_SMC_SETUP(cs)			(((cs) * 0x10))
> +#define ATMEL_HSMC_SETUP(cs)			(0x600 + ((cs) * 0x14))
> +#define ATMEL_SMC_PULSE(cs)			(((cs) * 0x10) + 0x4)
> +#define ATMEL_HSMC_PULSE(cs)			(0x600 + ((cs) * 0x14) + 0x4)
> +#define ATMEL_SMC_CYCLE(cs)			(((cs) * 0x10) + 0x8)
> +#define ATMEL_HSMC_CYCLE(cs)			(0x600 + ((cs) * 0x14) + 0x8)
> +#define ATMEL_SMC_NWE_SHIFT			0
> +#define ATMEL_SMC_NCS_WR_SHIFT			8
> +#define ATMEL_SMC_NRD_SHIFT			16
> +#define ATMEL_SMC_NCS_RD_SHIFT			24
> +
> +#define ATMEL_SMC_MODE(cs)			(((cs) * 0x10) + 0xc)
> +#define ATMEL_HSMC_MODE(cs)			(0x600 + ((cs) * 0x14) + 0x10)
> +#define ATMEL_SMC_MODE_READMODE_MASK		BIT(0)
> +#define ATMEL_SMC_MODE_READMODE_NCS		(0 << 0)
> +#define ATMEL_SMC_MODE_READMODE_NRD		(1 << 0)
> +#define ATMEL_SMC_MODE_WRITEMODE_MASK		BIT(1)
> +#define ATMEL_SMC_MODE_WRITEMODE_NCS		(0 << 1)
> +#define ATMEL_SMC_MODE_WRITEMODE_NWE		(1 << 1)
> +#define ATMEL_SMC_MODE_EXNWMODE_MASK		GENMASK(5, 4)
> +#define ATMEL_SMC_MODE_EXNWMODE_DISABLE		(0 << 4)
> +#define ATMEL_SMC_MODE_EXNWMODE_FROZEN		(2 << 4)
> +#define ATMEL_SMC_MODE_EXNWMODE_READY		(3 << 4)
> +#define ATMEL_SMC_MODE_BAT_MASK			BIT(8)
> +#define ATMEL_SMC_MODE_BAT_SELECT		(0 << 8)
> +#define ATMEL_SMC_MODE_BAT_WRITE		(1 << 8)
> +#define ATMEL_SMC_MODE_DBW_MASK			GENMASK(13, 12)
> +#define ATMEL_SMC_MODE_DBW_8			(0 << 12)
> +#define ATMEL_SMC_MODE_DBW_16			(1 << 12)
> +#define ATMEL_SMC_MODE_DBW_32			(2 << 12)
> +#define ATMEL_SMC_MODE_TDF_MASK			GENMASK(19, 16)
> +#define ATMEL_SMC_MODE_TDF(x)			(((x) - 1) << 16)
> +#define ATMEL_SMC_MODE_TDF_MAX			16
> +#define ATMEL_SMC_MODE_TDFMODE_OPTIMIZED	BIT(20)
> +#define ATMEL_SMC_MODE_PMEN			BIT(24)
> +#define ATMEL_SMC_MODE_PS_MASK			GENMASK(29, 28)
> +#define ATMEL_SMC_MODE_PS_4			(0 << 28)
> +#define ATMEL_SMC_MODE_PS_8			(1 << 28)
> +#define ATMEL_SMC_MODE_PS_16			(2 << 28)
> +#define ATMEL_SMC_MODE_PS_32			(3 << 28)
> +
> +#define ATMEL_HSMC_TIMINGS(cs)			(0x600 + ((cs) * 0x14) + 0xc)
> +#define ATMEL_HSMC_TIMINGS_OCMS			BIT(12)
> +#define ATMEL_HSMC_TIMINGS_RBNSEL(x)		((x) << 28)
> +#define ATMEL_HSMC_TIMINGS_NFSEL		BIT(31)
> +#define ATMEL_HSMC_TIMINGS_TCLR_SHIFT		0
> +#define ATMEL_HSMC_TIMINGS_TADL_SHIFT		4
> +#define ATMEL_HSMC_TIMINGS_TAR_SHIFT		8
> +#define ATMEL_HSMC_TIMINGS_TRR_SHIFT		16
> +#define ATMEL_HSMC_TIMINGS_TWB_SHIFT		24
> +
> +/**
> + * struct atmel_smc_cs_conf - SMC CS config as described in the datasheet.
> + * @setup: NCS/NWE/NRD setup timings (not applicable to at91rm9200)
> + * @pulse: NCS/NWE/NRD pulse timings (not applicable to at91rm9200)
> + * @cycle: NWE/NRD cycle timings (not applicable to at91rm9200)
> + * @timings: advanced NAND related timings (only applicable to HSMC)
> + * @mode: all kind of config parameters (see the fields definition above).
> + *	  The mode fields are different on at91rm9200
> + */
> +struct atmel_smc_cs_conf {
> +	u32 setup;
> +	u32 pulse;
> +	u32 cycle;
> +	u32 timings;
> +	u32 mode;
> +};
> +
> +/**
> + * atmel_smc_cs_conf_init - initialize a SMC CS conf
> + * @conf: the SMC CS conf to initialize
> + *
> + * Set all fields to 0 so that one can start defining a new config.
> + */
> +static inline void atmel_smc_cs_conf_init(struct atmel_smc_cs_conf *conf)
> +{
> +	memset(conf, 0, sizeof(*conf));
> +}
> +
> +/**
> + * atmel_smc_cs_encode_ncycles - encode a number of MCK clk cycles in the
> + *				 format expected by the SMC engine
> + * @ncycles: number of MCK clk cycles
> + * @msbpos: position of the MSB part of the timing field
> + * @msbwidth: width of the MSB part of the timing field
> + * @msbfactor: factor applied to the MSB
> + * @encodedval: param used to store the encoding result
> + *
> + * This function encodes the @ncycles value as described in the datasheet
> + * (section "SMC Setup/Pulse/Cycle/Timings Register"). This is a generic
> + * helper which called with different parameter depending on the encoding
> + * scheme.
> + *
> + * If the @ncycles value is too big to be encoded, -ERANGE is returned and
> + * the encodedval is contains the maximum val. Otherwise, 0 is returned.
> + */
> +static inline int atmel_smc_cs_encode_ncycles(unsigned int ncycles,
> +					      unsigned int msbpos,
> +					      unsigned int msbwidth,
> +					      unsigned int msbfactor,
> +					      unsigned int *encodedval)
> +{
> +	unsigned int lsbmask = GENMASK(msbpos - 1, 0);
> +	unsigned int msbmask = GENMASK(msbwidth - 1, 0);
> +	unsigned int msb, lsb;
> +	int ret = 0;
> +
> +	msb = ncycles / msbfactor;
> +	lsb = ncycles % msbfactor;
> +
> +	if (lsb > lsbmask) {
> +		lsb = 0;
> +		msb++;
> +	}
> +
> +	/*
> +	 * Let's just put the maximum we can if the requested setting does
> +	 * not fit in the register field.
> +	 * We still return -ERANGE in case the caller cares.
> +	 */
> +	if (msb > msbmask) {
> +		msb = msbmask;
> +		lsb = lsbmask;
> +		ret = -ERANGE;
> +	}
> +
> +	*encodedval = (msb << msbpos) | lsb;
> +
> +	return ret;
> +}
> +
> +/**
> + * atmel_smc_cs_conf_set_timing - set the SMC CS conf Txx parameter to a
> + *				  specific value
> + * @conf: SMC CS conf descriptor
> + * @shift: the position of the Txx field in the TIMINGS register
> + * @ncycles: value (expressed in MCK clk cycles) to assign to this Txx
> + *	     parameter
> + *
> + * This function encodes the @ncycles value as described in the datasheet
> + * (section "SMC Timings Register"), and then stores the result in the
> + * @conf->timings field at @shift position.
> + *
> + * Returns -EINVAL if shift is invalid, -ERANGE if ncycles does not fit in
> + * the field, and 0 otherwise.
> + */
> +static inline int atmel_smc_cs_conf_set_timing(struct atmel_smc_cs_conf *conf,
> +					       unsigned int shift,
> +					       unsigned int ncycles)
> +{
> +	unsigned int val;
> +	int ret;
> +
> +	if (shift != ATMEL_HSMC_TIMINGS_TCLR_SHIFT &&
> +	    shift != ATMEL_HSMC_TIMINGS_TADL_SHIFT &&
> +	    shift != ATMEL_HSMC_TIMINGS_TAR_SHIFT &&
> +	    shift != ATMEL_HSMC_TIMINGS_TRR_SHIFT &&
> +	    shift != ATMEL_HSMC_TIMINGS_TWB_SHIFT)
> +		return -EINVAL;
> +
> +	/*
> +	 * The formula described in atmel datasheets (section "HSMC Timings
> +	 * Register"):
> +	 *
> +	 * ncycles = (Txx[3] * 64) + Txx[2:0]
> +	 */
> +	ret = atmel_smc_cs_encode_ncycles(ncycles, 3, 1, 64, &val);
> +	conf->timings &= ~GENMASK(shift + 3, shift);
> +	conf->timings |= val << shift;
> +
> +	return ret;
> +}
> +
> +/**
> + * atmel_smc_cs_conf_set_setup - set the SMC CS conf xx_SETUP parameter to a
> + *				 specific value
> + * @conf: SMC CS conf descriptor
> + * @shift: the position of the xx_SETUP field in the SETUP register
> + * @ncycles: value (expressed in MCK clk cycles) to assign to this xx_SETUP
> + *	     parameter
> + *
> + * This function encodes the @ncycles value as described in the datasheet
> + * (section "SMC Setup Register"), and then stores the result in the
> + * @conf->setup field at @shift position.
> + *
> + * Returns -EINVAL if @shift is invalid, -ERANGE if @ncycles does not fit in
> + * the field, and 0 otherwise.
> + */
> +static inline int atmel_smc_cs_conf_set_setup(struct atmel_smc_cs_conf *conf,
> +					      unsigned int shift,
> +					      unsigned int ncycles)
> +{
> +	unsigned int val;
> +	int ret;
> +
> +	if (shift != ATMEL_SMC_NWE_SHIFT && shift != ATMEL_SMC_NCS_WR_SHIFT &&
> +	    shift != ATMEL_SMC_NRD_SHIFT && shift != ATMEL_SMC_NCS_RD_SHIFT)
> +		return -EINVAL;
> +
> +	/*
> +	 * The formula described in atmel datasheets (section "SMC Setup
> +	 * Register"):
> +	 *
> +	 * ncycles = (128 * xx_SETUP[5]) + xx_SETUP[4:0]
> +	 */
> +	ret = atmel_smc_cs_encode_ncycles(ncycles, 5, 1, 128, &val);
> +	conf->setup &= ~GENMASK(shift + 7, shift);
> +	conf->setup |= val << shift;
> +
> +	return ret;
> +}
> +
> +/**
> + * atmel_smc_cs_conf_set_pulse - set the SMC CS conf xx_PULSE parameter to a
> + *				 specific value
> + * @conf: SMC CS conf descriptor
> + * @shift: the position of the xx_PULSE field in the PULSE register
> + * @ncycles: value (expressed in MCK clk cycles) to assign to this xx_PULSE
> + *	     parameter
> + *
> + * This function encodes the @ncycles value as described in the datasheet
> + * (section "SMC Pulse Register"), and then stores the result in the
> + * @conf->setup field at @shift position.
> + *
> + * Returns -EINVAL if @shift is invalid, -ERANGE if @ncycles does not fit in
> + * the field, and 0 otherwise.
> + */
> +static inline int atmel_smc_cs_conf_set_pulse(struct atmel_smc_cs_conf *conf,
> +					      unsigned int shift,
> +					      unsigned int ncycles)
> +{
> +	unsigned int val;
> +	int ret;
> +
> +	if (shift != ATMEL_SMC_NWE_SHIFT && shift != ATMEL_SMC_NCS_WR_SHIFT &&
> +	    shift != ATMEL_SMC_NRD_SHIFT && shift != ATMEL_SMC_NCS_RD_SHIFT)
> +		return -EINVAL;
> +
> +	/*
> +	 * The formula described in atmel datasheets (section "SMC Pulse
> +	 * Register"):
> +	 *
> +	 * ncycles = (256 * xx_PULSE[6]) + xx_PULSE[5:0]
> +	 */
> +	ret = atmel_smc_cs_encode_ncycles(ncycles, 6, 1, 256, &val);
> +	conf->pulse &= ~GENMASK(shift + 7, shift);
> +	conf->pulse |= val << shift;
> +
> +	return ret;
> +}
> +
> +/**
> + * atmel_smc_cs_conf_set_cycle - set the SMC CS conf xx_CYCLE parameter to a
> + *				 specific value
> + * @conf: SMC CS conf descriptor
> + * @shift: the position of the xx_CYCLE field in the CYCLE register
> + * @ncycles: value (expressed in MCK clk cycles) to assign to this xx_CYCLE
> + *	     parameter
> + *
> + * This function encodes the @ncycles value as described in the datasheet
> + * (section "SMC Pulse Register"), and then stores the result in the
> + * @conf->setup field at @shift position.
> + *
> + * Returns -EINVAL if @shift is invalid, -ERANGE if @ncycles does not fit in
> + * the field, and 0 otherwise.
> + */
> +static inline int atmel_smc_cs_conf_set_cycle(struct atmel_smc_cs_conf *conf,
> +					      unsigned int shift,
> +					      unsigned int ncycles)
> +{
> +	unsigned int val;
> +	int ret;
> +
> +	if (shift != ATMEL_SMC_NWE_SHIFT && shift != ATMEL_SMC_NRD_SHIFT)
> +		return -EINVAL;
> +
> +	/*
> +	 * The formula described in atmel datasheets (section "SMC Cycle
> +	 * Register"):
> +	 *
> +	 * ncycles = (xx_CYCLE[8:7] * 256) + xx_CYCLE[6:0]
> +	 */
> +	ret = atmel_smc_cs_encode_ncycles(ncycles, 7, 2, 256, &val);
> +	conf->cycle &= ~GENMASK(shift + 15, shift);
> +	conf->cycle |= val << shift;
> +
> +	return ret;
> +}
> +
> +/**
> + * atmel_smc_cs_conf_apply - apply an SMC CS conf
> + * @regmap: the SMC regmap
> + * @cs: the CS id
> + * @conf the SMC CS conf to apply
> + *
> + * Applies an SMC CS configuration.
> + * Only valid on at91sam9/avr32 SoCs.
> + */
> +static inline void atmel_smc_cs_conf_apply(struct regmap *regmap, int cs,
> +					   const struct atmel_smc_cs_conf *conf)
> +{
> +	regmap_write(regmap, ATMEL_SMC_SETUP(cs), conf->setup);
> +	regmap_write(regmap, ATMEL_SMC_PULSE(cs), conf->pulse);
> +	regmap_write(regmap, ATMEL_SMC_CYCLE(cs), conf->cycle);
> +	regmap_write(regmap, ATMEL_SMC_MODE(cs), conf->mode);
> +}
> +
> +/**
> + * atmel_hsmc_cs_conf_apply - apply an SMC CS conf
> + * @regmap: the HSMC regmap
> + * @cs: the CS id
> + * @conf the SMC CS conf to apply
> + *
> + * Applies an SMC CS configuration.
> + * Only valid on post-sama5 SoCs.
> + */
> +static inline void atmel_hsmc_cs_conf_apply(struct regmap *regmap, int cs,
> +					const struct atmel_smc_cs_conf *conf)
> +{
> +	regmap_write(regmap, ATMEL_HSMC_SETUP(cs), conf->setup);
> +	regmap_write(regmap, ATMEL_HSMC_PULSE(cs), conf->pulse);
> +	regmap_write(regmap, ATMEL_HSMC_CYCLE(cs), conf->cycle);
> +	regmap_write(regmap, ATMEL_HSMC_TIMINGS(cs), conf->timings);
> +	regmap_write(regmap, ATMEL_HSMC_MODE(cs), conf->mode);
> +}
> +
> +/**
> + * atmel_smc_cs_conf_get - retrieve the current SMC CS conf
> + * @regmap: the SMC regmap
> + * @cs: the CS id
> + * @conf: the SMC CS conf object to store the current conf
> + *
> + * Retrieve the SMC CS configuration.
> + * Only valid on at91sam9/avr32 SoCs.
> + */
> +static inline void atmel_smc_cs_conf_get(struct regmap *regmap, int cs,
> +					 struct atmel_smc_cs_conf *conf)
> +{
> +	regmap_read(regmap, ATMEL_SMC_SETUP(cs), &conf->setup);
> +	regmap_read(regmap, ATMEL_SMC_PULSE(cs), &conf->pulse);
> +	regmap_read(regmap, ATMEL_SMC_CYCLE(cs), &conf->cycle);
> +	regmap_read(regmap, ATMEL_SMC_MODE(cs), &conf->mode);
> +}
> +
> +/**
> + * atmel_hsmc_cs_conf_get - retrieve the current SMC CS conf
> + * @regmap: the HSMC regmap
> + * @cs: the CS id
> + * @conf: the SMC CS conf object to store the current conf
> + *
> + * Retrieve the SMC CS configuration.
> + * Only valid on post-sama5 SoCs.
> + */
> +static inline void atmel_hsmc_cs_conf_get(struct regmap *regmap, int cs,
> +					  struct atmel_smc_cs_conf *conf)
> +{
> +	regmap_read(regmap, ATMEL_HSMC_SETUP(cs), &conf->setup);
> +	regmap_read(regmap, ATMEL_HSMC_PULSE(cs), &conf->pulse);
> +	regmap_read(regmap, ATMEL_HSMC_CYCLE(cs), &conf->cycle);
> +	regmap_read(regmap, ATMEL_HSMC_TIMINGS(cs), &conf->timings);
> +	regmap_read(regmap, ATMEL_HSMC_MODE(cs), &conf->mode);
> +}
>  
>  /*
>   * This function converts a setup timing expressed in nanoseconds into an

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org â Open source software for ARM SoCs
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