linux-kernel - Re: [PATCH 2/2] spi: spi-geni-qcom: Add SPI SLAVE mode support for GENI based QuPv3

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Date:   Wed, 14 Jun 2023 00:12:42 +0530
From:   Vijaya Krishna Nivarthi <quic_vnivarth@...cinc.com>
To:     Praveen Talari <quic_ptalari@...cinc.com>, <agross@...nel.org>,
        <andersson@...nel.org>, <konrad.dybcio@...aro.org>,
        <broonie@...nel.org>, <linux-arm-msm@...r.kernel.org>,
        <linux-spi@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:     <quic_msavaliy@...cinc.com>, <quic_vtanuku@...cinc.com>,
        <quic_arandive@...cinc.com>
Subject: Re: [PATCH 2/2] spi: spi-geni-qcom: Add SPI SLAVE mode support for
 GENI based QuPv3

Hi,


On 6/13/2023 12:22 PM, Praveen Talari wrote:
> Add SPI SLAVE mode support for GENI based QuPv3.
>
> Signed-off-by: Praveen Talari <quic_ptalari@...cinc.com>
> ---
>   drivers/spi/spi-geni-qcom.c | 55 +++++++++++++++++++++++++++++++++----
>   1 file changed, 49 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c
> index 206cc04bb1ed..2e3ae29e79e0 100644
> --- a/drivers/spi/spi-geni-qcom.c
> +++ b/drivers/spi/spi-geni-qcom.c
> @@ -12,6 +12,7 @@
>   #include <linux/platform_device.h>
>   #include <linux/pm_opp.h>
>   #include <linux/pm_runtime.h>
> +#include <linux/property.h>
>   #include <linux/soc/qcom/geni-se.h>
>   #include <linux/spi/spi.h>
>   #include <linux/spinlock.h>
> @@ -52,6 +53,9 @@
>   #define SPI_CS_CLK_DELAY_MSK		GENMASK(19, 10)
>   #define SPI_CS_CLK_DELAY_SHFT		10
>   
> +#define SE_SPI_SLAVE_EN				(0x2BC)
> +#define SPI_SLAVE_EN				BIT(0)
> +
>   /* M_CMD OP codes for SPI */
>   #define SPI_TX_ONLY		1
>   #define SPI_RX_ONLY		2
> @@ -99,6 +103,24 @@ struct spi_geni_master {
>   	int cur_xfer_mode;
>   };
>   
> +static struct spi_master *get_spi_master(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct spi_master *spi = platform_get_drvdata(pdev);
> +
> +	return spi;
> +}

I would recommend to drop this function.

The objective of this is to retrieve spi_master

The call sequence is probe() => geni_init() => get_spi_master()

probe() already has access to spi_master

why not simply pass it down to geni_init()?

Thank you.

> +
> +static void spi_slv_setup(struct spi_geni_master *mas)
> +{
> +	struct geni_se *se = &mas->se;
> +
> +	writel(SPI_SLAVE_EN, se->base + SE_SPI_SLAVE_EN);
> +	writel(GENI_IO_MUX_0_EN, se->base + GENI_OUTPUT_CTRL);
> +	writel(START_TRIGGER, se->base + SE_GENI_CFG_SEQ_START);
> +	dev_info(mas->dev, "spi slave setup done\n");
> +}
> +
>   static int get_spi_clk_cfg(unsigned int speed_hz,
>   			struct spi_geni_master *mas,
>   			unsigned int *clk_idx,
> @@ -140,12 +162,18 @@ static void handle_se_timeout(struct spi_master *spi,
>   	const struct spi_transfer *xfer;
>   
>   	spin_lock_irq(&mas->lock);
> -	reinit_completion(&mas->cancel_done);
>   	if (mas->cur_xfer_mode == GENI_SE_FIFO)
>   		writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
>   
>   	xfer = mas->cur_xfer;
>   	mas->cur_xfer = NULL;
> +
> +	if (spi->slave) {
> +		spin_unlock_irq(&mas->lock);
> +		goto unmap_if_dma;
> +	}
> +
> +	reinit_completion(&mas->cancel_done);
>   	geni_se_cancel_m_cmd(se);
>   	spin_unlock_irq(&mas->lock);
>   
> @@ -541,6 +569,8 @@ static bool geni_can_dma(struct spi_controller *ctlr,
>   
>   	if (mas->cur_xfer_mode == GENI_GPI_DMA)
>   		return true;
> +	if (ctlr->slave)
> +		return true;
>   
>   	len = get_xfer_len_in_words(xfer, mas);
>   	fifo_size = mas->tx_fifo_depth * mas->fifo_width_bits / mas->cur_bits_per_word;
> @@ -619,6 +649,7 @@ static void spi_geni_release_dma_chan(struct spi_geni_master *mas)
>   
>   static int spi_geni_init(struct spi_geni_master *mas)
>   {
> +	struct spi_master *spi = get_spi_master(mas->dev);
>   	struct geni_se *se = &mas->se;
>   	unsigned int proto, major, minor, ver;
>   	u32 spi_tx_cfg, fifo_disable;
> @@ -627,7 +658,14 @@ static int spi_geni_init(struct spi_geni_master *mas)
>   	pm_runtime_get_sync(mas->dev);
>   
>   	proto = geni_se_read_proto(se);
> -	if (proto != GENI_SE_SPI) {
> +
> +	if (spi->slave) {
> +		if (proto != GENI_SE_SPI_SLAVE) {
> +			dev_err(mas->dev, "Invalid proto %d\n", proto);
> +			goto out_pm;
> +		}
> +		spi_slv_setup(mas);
> +	} else if (proto != GENI_SE_SPI) {
>   		dev_err(mas->dev, "Invalid proto %d\n", proto);
>   		goto out_pm;
>   	}
> @@ -677,9 +715,11 @@ static int spi_geni_init(struct spi_geni_master *mas)
>   	}
>   
>   	/* We always control CS manually */
> -	spi_tx_cfg = readl(se->base + SE_SPI_TRANS_CFG);
> -	spi_tx_cfg &= ~CS_TOGGLE;
> -	writel(spi_tx_cfg, se->base + SE_SPI_TRANS_CFG);
> +	if (!spi->slave) {
> +		spi_tx_cfg = readl(se->base + SE_SPI_TRANS_CFG);
> +		spi_tx_cfg &= ~CS_TOGGLE;
> +		writel(spi_tx_cfg, se->base + SE_SPI_TRANS_CFG);
> +	}
>   
>   out_pm:
>   	pm_runtime_put(mas->dev);
> @@ -1072,6 +1112,9 @@ static int spi_geni_probe(struct platform_device *pdev)
>   	pm_runtime_set_autosuspend_delay(&pdev->dev, 250);
>   	pm_runtime_enable(dev);
>   
> +	if (device_property_read_bool(&pdev->dev, "qcom,slv-ctrl"))
> +		spi->slave = true;
> +
>   	ret = geni_icc_get(&mas->se, NULL);
>   	if (ret)
>   		goto spi_geni_probe_runtime_disable;
> @@ -1092,7 +1135,7 @@ static int spi_geni_probe(struct platform_device *pdev)
>   	 * for dma (gsi) mode, the gsi will set cs based on params passed in
>   	 * TRE
>   	 */
> -	if (mas->cur_xfer_mode == GENI_SE_FIFO)
> +	if (!spi->slave && mas->cur_xfer_mode == GENI_SE_FIFO)
>   		spi->set_cs = spi_geni_set_cs;
>   
>   	ret = request_irq(mas->irq, geni_spi_isr, 0, dev_name(dev), spi);