Re: [RFC PATCH v1] spi: fsl_spi: Convert to transfer_one

[Christophe Leroy]

Le 18/08/2022 à 15:38, Christophe Leroy a écrit :
> Let the core handle all the chipselect bakery and replace
> transfer_one_message() by transfer_one() and prepare_message().
> 
> At the time being, there is fsl_spi_cs_control() to handle
> chipselects. That function handles both GPIO and non-GPIO
> chipselects. The GPIO chipselects will now be handled by
> the core directly, so only handle non-GPIO chipselects and
> hook it to ->set_cs

Any comment for/about this conversion ?
Did I do it the right way ? Any recommendation ?

Thanks
Christophe


> 
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> ---
> Sending as an RFC as I'm not 100% sure of the correctness.
> I successfully tested it on the hardware I have though.
> Not sure about the change from m->is_dma_mapped to !!t->tx_dma || !!t->rx_dma
> ---
>   drivers/spi/spi-fsl-spi.c | 157 +++++++++++---------------------------
>   1 file changed, 43 insertions(+), 114 deletions(-)
> 
> diff --git a/drivers/spi/spi-fsl-spi.c b/drivers/spi/spi-fsl-spi.c
> index bdf94cc7be1a..731624f157fc 100644
> --- a/drivers/spi/spi-fsl-spi.c
> +++ b/drivers/spi/spi-fsl-spi.c
> @@ -111,32 +111,6 @@ static void fsl_spi_change_mode(struct spi_device *spi)
>   	local_irq_restore(flags);
>   }
>   
> -static void fsl_spi_chipselect(struct spi_device *spi, int value)
> -{
> -	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);
> -	struct fsl_spi_platform_data *pdata;
> -	struct spi_mpc8xxx_cs	*cs = spi->controller_state;
> -
> -	pdata = spi->dev.parent->parent->platform_data;
> -
> -	if (value == BITBANG_CS_INACTIVE) {
> -		if (pdata->cs_control)
> -			pdata->cs_control(spi, false);
> -	}
> -
> -	if (value == BITBANG_CS_ACTIVE) {
> -		mpc8xxx_spi->rx_shift = cs->rx_shift;
> -		mpc8xxx_spi->tx_shift = cs->tx_shift;
> -		mpc8xxx_spi->get_rx = cs->get_rx;
> -		mpc8xxx_spi->get_tx = cs->get_tx;
> -
> -		fsl_spi_change_mode(spi);
> -
> -		if (pdata->cs_control)
> -			pdata->cs_control(spi, true);
> -	}
> -}
> -
>   static void fsl_spi_qe_cpu_set_shifts(u32 *rx_shift, u32 *tx_shift,
>   				      int bits_per_word, int msb_first)
>   {
> @@ -354,15 +328,11 @@ static int fsl_spi_bufs(struct spi_device *spi, struct spi_transfer *t,
>   	return mpc8xxx_spi->count;
>   }
>   
> -static int fsl_spi_do_one_msg(struct spi_master *master,
> -			      struct spi_message *m)
> +static int fsl_spi_prepare_message(struct spi_controller *ctlr,
> +				   struct spi_message *m)
>   {
> -	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(master);
> -	struct spi_device *spi = m->spi;
> -	struct spi_transfer *t, *first;
> -	unsigned int cs_change;
> -	const int nsecs = 50;
> -	int status, last_bpw;
> +	struct mpc8xxx_spi *mpc8xxx_spi = spi_controller_get_devdata(ctlr);
> +	struct spi_transfer *t;
>   
>   	/*
>   	 * In CPU mode, optimize large byte transfers to use larger
> @@ -378,62 +348,30 @@ static int fsl_spi_do_one_msg(struct spi_master *master,
>   				t->bits_per_word = 16;
>   		}
>   	}
> +	return 0;
> +}
>   
> -	/* Don't allow changes if CS is active */
> -	cs_change = 1;
> -	list_for_each_entry(t, &m->transfers, transfer_list) {
> -		if (cs_change)
> -			first = t;
> -		cs_change = t->cs_change;
> -		if (first->speed_hz != t->speed_hz) {
> -			dev_err(&spi->dev,
> -				"speed_hz cannot change while CS is active\n");
> -			return -EINVAL;
> -		}
> -	}
> -
> -	last_bpw = -1;
> -	cs_change = 1;
> -	status = -EINVAL;
> -	list_for_each_entry(t, &m->transfers, transfer_list) {
> -		if (cs_change || last_bpw != t->bits_per_word)
> -			status = fsl_spi_setup_transfer(spi, t);
> -		if (status < 0)
> -			break;
> -		last_bpw = t->bits_per_word;
> -
> -		if (cs_change) {
> -			fsl_spi_chipselect(spi, BITBANG_CS_ACTIVE);
> -			ndelay(nsecs);
> -		}
> -		cs_change = t->cs_change;
> -		if (t->len)
> -			status = fsl_spi_bufs(spi, t, m->is_dma_mapped);
> -		if (status) {
> -			status = -EMSGSIZE;
> -			break;
> -		}
> -		m->actual_length += t->len;
> -
> -		spi_transfer_delay_exec(t);
> -
> -		if (cs_change) {
> -			ndelay(nsecs);
> -			fsl_spi_chipselect(spi, BITBANG_CS_INACTIVE);
> -			ndelay(nsecs);
> -		}
> -	}
> +static int fsl_spi_transfer_one(struct spi_controller *controller,
> +				struct spi_device *spi,
> +				struct spi_transfer *t)
> +{
> +	int status;
>   
> -	m->status = status;
> +	status = fsl_spi_setup_transfer(spi, t);
> +	if (status < 0)
> +		return status;
> +	if (t->len)
> +		status = fsl_spi_bufs(spi, t, !!t->tx_dma || !!t->rx_dma);
> +	if (status > 0)
> +		return -EMSGSIZE;
>   
> -	if (status || !cs_change) {
> -		ndelay(nsecs);
> -		fsl_spi_chipselect(spi, BITBANG_CS_INACTIVE);
> -	}
> +	return status;
> +}
>   
> -	fsl_spi_setup_transfer(spi, NULL);
> -	spi_finalize_current_message(master);
> -	return 0;
> +static int fsl_spi_unprepare_message(struct spi_controller *controller,
> +				     struct spi_message *msg)
> +{
> +	return fsl_spi_setup_transfer(msg->spi, NULL);
>   }
>   
>   static int fsl_spi_setup(struct spi_device *spi)
> @@ -482,9 +420,6 @@ static int fsl_spi_setup(struct spi_device *spi)
>   		return retval;
>   	}
>   
> -	/* Initialize chipselect - might be active for SPI_CS_HIGH mode */
> -	fsl_spi_chipselect(spi, BITBANG_CS_INACTIVE);
> -
>   	return 0;
>   }
>   
> @@ -557,9 +492,7 @@ static void fsl_spi_grlib_cs_control(struct spi_device *spi, bool on)
>   	u32 slvsel;
>   	u16 cs = spi->chip_select;
>   
> -	if (spi->cs_gpiod) {
> -		gpiod_set_value(spi->cs_gpiod, on);
> -	} else if (cs < mpc8xxx_spi->native_chipselects) {
> +	if (cs < mpc8xxx_spi->native_chipselects) {
>   		slvsel = mpc8xxx_spi_read_reg(&reg_base->slvsel);
>   		slvsel = on ? (slvsel | (1 << cs)) : (slvsel & ~(1 << cs));
>   		mpc8xxx_spi_write_reg(&reg_base->slvsel, slvsel);
> @@ -568,7 +501,6 @@ static void fsl_spi_grlib_cs_control(struct spi_device *spi, bool on)
>   
>   static void fsl_spi_grlib_probe(struct device *dev)
>   {
> -	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
>   	struct spi_master *master = dev_get_drvdata(dev);
>   	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(master);
>   	struct fsl_spi_reg __iomem *reg_base = mpc8xxx_spi->reg_base;
> @@ -588,7 +520,18 @@ static void fsl_spi_grlib_probe(struct device *dev)
>   		mpc8xxx_spi_write_reg(&reg_base->slvsel, 0xffffffff);
>   	}
>   	master->num_chipselect = mpc8xxx_spi->native_chipselects;
> -	pdata->cs_control = fsl_spi_grlib_cs_control;
> +	master->set_cs = fsl_spi_grlib_cs_control;
> +}
> +
> +static void fsl_spi_cs_control(struct spi_device *spi, bool on)
> +{
> +	struct device *dev = spi->dev.parent->parent;
> +	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
> +	struct mpc8xxx_spi_probe_info *pinfo = to_of_pinfo(pdata);
> +
> +	if (WARN_ON_ONCE(!pinfo->immr_spi_cs))
> +		return;
> +	iowrite32be(on ? 0 : SPI_BOOT_SEL_BIT, pinfo->immr_spi_cs);
>   }
>   
>   static struct spi_master *fsl_spi_probe(struct device *dev,
> @@ -613,8 +556,11 @@ static struct spi_master *fsl_spi_probe(struct device *dev,
>   
>   	master->setup = fsl_spi_setup;
>   	master->cleanup = fsl_spi_cleanup;
> -	master->transfer_one_message = fsl_spi_do_one_msg;
> +	master->prepare_message = fsl_spi_prepare_message;
> +	master->transfer_one = fsl_spi_transfer_one;
> +	master->unprepare_message = fsl_spi_unprepare_message;
>   	master->use_gpio_descriptors = true;
> +	master->set_cs = fsl_spi_cs_control;
>   
>   	mpc8xxx_spi = spi_master_get_devdata(master);
>   	mpc8xxx_spi->max_bits_per_word = 32;
> @@ -688,21 +634,6 @@ static struct spi_master *fsl_spi_probe(struct device *dev,
>   	return ERR_PTR(ret);
>   }
>   
> -static void fsl_spi_cs_control(struct spi_device *spi, bool on)
> -{
> -	if (spi->cs_gpiod) {
> -		gpiod_set_value(spi->cs_gpiod, on);
> -	} else {
> -		struct device *dev = spi->dev.parent->parent;
> -		struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
> -		struct mpc8xxx_spi_probe_info *pinfo = to_of_pinfo(pdata);
> -
> -		if (WARN_ON_ONCE(!pinfo->immr_spi_cs))
> -			return;
> -		iowrite32be(on ? 0 : SPI_BOOT_SEL_BIT, pinfo->immr_spi_cs);
> -	}
> -}
> -
>   static int of_fsl_spi_probe(struct platform_device *ofdev)
>   {
>   	struct device *dev = &ofdev->dev;
> @@ -744,12 +675,10 @@ static int of_fsl_spi_probe(struct platform_device *ofdev)
>   		ret = gpiod_count(dev, "cs");
>   		if (ret < 0)
>   			ret = 0;
> -		if (ret == 0 && !spisel_boot) {
> +		if (ret == 0 && !spisel_boot)
>   			pdata->max_chipselect = 1;
> -		} else {
> +		else
>   			pdata->max_chipselect = ret + spisel_boot;
> -			pdata->cs_control = fsl_spi_cs_control;
> -		}
>   	}
>   
>   	ret = of_address_to_resource(np, 0, &mem);