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Message-ID: <d39df510-c0d0-97c2-4a35-e28829ddd761@linaro.org>
Date:   Tue, 13 Jun 2023 14:27:02 +0200
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To:     Praveen Talari <quic_ptalari@quicinc.com>, agross@kernel.org,
        andersson@kernel.org, broonie@kernel.org,
        linux-arm-msm@vger.kernel.org, linux-spi@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     quic_msavaliy@quicinc.com, quic_vtanuku@quicinc.com,
        quic_vnivarth@quicinc.com, quic_arandive@quicinc.com
References: <20230613065229.5619-1-quic_ptalari@quicinc.com>
 <20230613065229.5619-3-quic_ptalari@quicinc.com>
From:   Konrad Dybcio <konrad.dybcio@linaro.org>
Subject: Re: [PATCH 2/2] spi: spi-geni-qcom: Add SPI SLAVE mode support for
 GENI based QuPv3
In-Reply-To: <20230613065229.5619-3-quic_ptalari@quicinc.com>
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On 13.06.2023 08:52, Praveen Talari wrote:
> Add SPI SLAVE mode support for GENI based QuPv3.
> 
Copying the commit title in the commit message is a bit lackluster for
adding new functionality.

> Signed-off-by: Praveen Talari <quic_ptalari@quicinc.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;
> +}
> +
> +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");
dev_dbg

> +}
> +
>  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);
Moving reiniting cancel_done after possibly writing the register
for both mas/slv cases sounds like a separate change - is it
necessary?

>  	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;
Regardless of the xfer mode?

>  
>  	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;
Missing dt-bindings

Konrad
> +
>  	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);