Subject: Re: [PATCH v6 13/13] spi: atmel-quadspi: add support for sam9x60 qspi controller

From: Boris Brezillon <[email-masked]>
Date: Tue, 5 Feb 2019 23:23:35 +0100

On Tue, 5 Feb 2019 17:33:38 +0000
<[email-masked]> wrote:

> From: Tudor Ambarus <[email-masked]>
> 
> The sam9x60 qspi controller uses 2 clocks, one for the peripheral register
> access, the other for the qspi core and phy. Both are mandatory. It uses
> different transfer type bits in IFR register. It has dedicated registers
> to specify a read or a write instruction: Read Instruction Code Register
> (RICR) and Write Instruction Code Register (WICR). ICR/RICR/WICR have
> identical fields.
> 
> Tested with sst26vf064b jedec,spi-nor flash. Backward compatibility test
> done on sama5d2 qspi controller and mx25l25635e jedec,spi-nor flash.
> 
> Signed-off-by: Tudor Ambarus <[email-masked]>

Reviewed-by: Boris Brezillon <[email-masked]>

> ---
> v6: add a caps instance to the sama5d2 entry instead of allowing caps
>     to be NULL
> v5:
> - use WICR for sam9x60
> - remove ops hooks and introduce caps->has_ricr
> - get rid of the cfg struct
> - group IO accesses together in atmel_qspi_set_cfg()
> v4:
> - drop local variables that kept aq->regs and &pdev->dev, the compiler
>   should be smart enough to store them in a register
> - add comment saying QSPI_IFR_APBTFRTYP_READ is defined in sam9x60
> - s/sama5d2_qspi_modes/atmel_qspi_modes, modes are the same both
>   controllers
> - fix kernel doc header
> - move comment in function body
> v3:
> - reorganize the code and change ops functions pointers to avoid code
>   duplication. From the IP perspective, the transfer type bits are
>   different, and what registers are written: ricr/wicr instead of icr.
> - treat just regular spi transfers. Mem transfers will be added together
>   with dirmap support.
> v2:
> - rework clock handling
> - reorder setting of register values in set_cfg() calls -> move functions
>   that can fail in the upper part of the function body.
> 
>  drivers/spi/atmel-quadspi.c | 163 ++++++++++++++++++++++++++++++++++----------
>  1 file changed, 128 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c
> index 336501d962e5..fffc21cd5f79 100644
> --- a/drivers/spi/atmel-quadspi.c
> +++ b/drivers/spi/atmel-quadspi.c
> @@ -19,6 +19,7 @@
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> +#include <linux/of_platform.h>
>  #include <linux/platform_device.h>
>  #include <linux/spi/spi-mem.h>
>  
> @@ -35,7 +36,9 @@
>  
>  #define QSPI_IAR     0x0030  /* Instruction Address Register */
>  #define QSPI_ICR     0x0034  /* Instruction Code Register */
> +#define QSPI_WICR    0x0034  /* Write Instruction Code Register */
>  #define QSPI_IFR     0x0038  /* Instruction Frame Register */
> +#define QSPI_RICR    0x003C  /* Read Instruction Code Register */
>  
>  #define QSPI_SMR     0x0040  /* Scrambling Mode Register */
>  #define QSPI_SKR     0x0044  /* Scrambling Key Register */
> @@ -88,7 +91,7 @@
>  #define QSPI_SCR_DLYBS_MASK             GENMASK(23, 16)
>  #define QSPI_SCR_DLYBS(n)               (((n) << 16) & QSPI_SCR_DLYBS_MASK)
>  
> -/* Bitfields in QSPI_ICR (Instruction Code Register) */
> +/* Bitfields in QSPI_ICR (Read/Write Instruction Code Register) */
>  #define QSPI_ICR_INST_MASK              GENMASK(7, 0)
>  #define QSPI_ICR_INST(inst)             (((inst) << 0) & QSPI_ICR_INST_MASK)
>  #define QSPI_ICR_OPT_MASK               GENMASK(23, 16)
> @@ -118,6 +121,7 @@
>  #define QSPI_IFR_CRM                    BIT(14)
>  #define QSPI_IFR_NBDUM_MASK             GENMASK(20, 16)
>  #define QSPI_IFR_NBDUM(n)               (((n) << 16) & QSPI_IFR_NBDUM_MASK)
> +#define QSPI_IFR_APBTFRTYP_READ		BIT(24)	/* Defined in SAM9X60 */
>  
>  /* Bitfields in QSPI_SMR (Scrambling Mode Register) */
>  #define QSPI_SMR_SCREN                  BIT(0)
> @@ -133,12 +137,18 @@
>  #define QSPI_WPSR_WPVSRC_MASK           GENMASK(15, 8)
>  #define QSPI_WPSR_WPVSRC(src)           (((src) << 8) & QSPI_WPSR_WPVSRC)
>  
> +struct atmel_qspi_caps {
> +	bool has_qspick;
> +	bool has_ricr;
> +};
>  
>  struct atmel_qspi {
>  	void __iomem		*regs;
>  	void __iomem		*mem;
>  	struct clk		*pclk;
> +	struct clk		*qspick;
>  	struct platform_device	*pdev;
> +	const struct atmel_qspi_caps *caps;
>  	u32			pending;
>  	u32			mr;
>  	struct completion	cmd_completion;
> @@ -151,7 +161,7 @@ struct atmel_qspi_mode {
>  	u32 config;
>  };
>  
> -static const struct atmel_qspi_mode sama5d2_qspi_modes[] = {
> +static const struct atmel_qspi_mode atmel_qspi_modes[] = {
>  	{ 1, 1, 1, QSPI_IFR_WIDTH_SINGLE_BIT_SPI },
>  	{ 1, 1, 2, QSPI_IFR_WIDTH_DUAL_OUTPUT },
>  	{ 1, 1, 4, QSPI_IFR_WIDTH_QUAD_OUTPUT },
> @@ -180,8 +190,8 @@ static int atmel_qspi_find_mode(const struct spi_mem_op *op)
>  {
>  	u32 i;
>  
> -	for (i = 0; i < ARRAY_SIZE(sama5d2_qspi_modes); i++)
> -		if (atmel_qspi_is_compatible(op, &sama5d2_qspi_modes[i]))
> +	for (i = 0; i < ARRAY_SIZE(atmel_qspi_modes); i++)
> +		if (atmel_qspi_is_compatible(op, &atmel_qspi_modes[i]))
>  			return i;
>  
>  	return -ENOTSUPP;
> @@ -201,36 +211,37 @@ static bool atmel_qspi_supports_op(struct spi_mem *mem,
>  	return true;
>  }
>  
> -static int atmel_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
> +static int atmel_qspi_set_cfg(struct atmel_qspi *aq,
> +			      const struct spi_mem_op *op, u32 *offset)
>  {
> -	struct atmel_qspi *aq = spi_controller_get_devdata(mem->spi->master);
> -	int mode;
> +	u32 iar, icr, ifr;
>  	u32 dummy_cycles = 0;
> -	u32 iar, icr, ifr, sr;
> -	int err = 0;
> +	int mode;
>  
>  	iar = 0;
>  	icr = QSPI_ICR_INST(op->cmd.opcode);
>  	ifr = QSPI_IFR_INSTEN;
>  
> -	/*
> -	 * If the QSPI controller is set in regular SPI mode, set it in
> -	 * Serial Memory Mode (SMM).
> -	 */
> -	if (aq->mr != QSPI_MR_SMM) {
> -		writel_relaxed(QSPI_MR_SMM, aq->regs + QSPI_MR);
> -		aq->mr = QSPI_MR_SMM;
> -	}
> -
>  	mode = atmel_qspi_find_mode(op);
>  	if (mode < 0)
>  		return mode;
> -
> -	ifr |= sama5d2_qspi_modes[mode].config;
> +	ifr |= atmel_qspi_modes[mode].config;
>  
>  	if (op->dummy.buswidth && op->dummy.nbytes)
>  		dummy_cycles = op->dummy.nbytes * 8 / op->dummy.buswidth;
>  
> +	/*
> +	 * The controller allows 24 and 32-bit addressing while NAND-flash
> +	 * requires 16-bit long. Handling 8-bit long addresses is done using
> +	 * the option field. For the 16-bit addresses, the workaround depends
> +	 * of the number of requested dummy bits. If there are 8 or more dummy
> +	 * cycles, the address is shifted and sent with the first dummy byte.
> +	 * Otherwise opcode is disabled and the first byte of the address
> +	 * contains the command opcode (works only if the opcode and address
> +	 * use the same buswidth). The limitation is when the 16-bit address is
> +	 * used without enough dummy cycles and the opcode is using a different
> +	 * buswidth than the address.
> +	 */
>  	if (op->addr.buswidth) {
>  		switch (op->addr.nbytes) {
>  		case 0:
> @@ -264,6 +275,9 @@ static int atmel_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>  		}
>  	}
>  
> +	/* offset of the data access in the QSPI memory space */
> +	*offset = iar;
> +
>  	/* Set number of dummy cycles */
>  	if (dummy_cycles)
>  		ifr |= QSPI_IFR_NBDUM(dummy_cycles);
> @@ -272,16 +286,51 @@ static int atmel_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>  	if (op->data.nbytes)
>  		ifr |= QSPI_IFR_DATAEN;
>  
> -	if (op->data.dir == SPI_MEM_DATA_OUT)
> -		ifr |= QSPI_IFR_SAMA5D2_WRITE_TRSFR;
> +	/*
> +	 * If the QSPI controller is set in regular SPI mode, set it in
> +	 * Serial Memory Mode (SMM).
> +	 */
> +	if (aq->mr != QSPI_MR_SMM) {
> +		writel_relaxed(QSPI_MR_SMM, aq->regs + QSPI_MR);
> +		aq->mr = QSPI_MR_SMM;
> +	}
>  
>  	/* Clear pending interrupts */
>  	(void)readl_relaxed(aq->regs + QSPI_SR);
>  
> -	/* Set QSPI Instruction Frame registers */
> -	writel_relaxed(iar, aq->regs + QSPI_IAR);
> -	writel_relaxed(icr, aq->regs + QSPI_ICR);
> -	writel_relaxed(ifr, aq->regs + QSPI_IFR);
> +	if (aq->caps->has_ricr) {
> +		if (!op->addr.nbytes && op->data.dir == SPI_MEM_DATA_IN)
> +			ifr |= QSPI_IFR_APBTFRTYP_READ;
> +
> +		/* Set QSPI Instruction Frame registers */
> +		writel_relaxed(iar, aq->regs + QSPI_IAR);
> +		if (op->data.dir == SPI_MEM_DATA_IN)
> +			writel_relaxed(icr, aq->regs + QSPI_RICR);
> +		else
> +			writel_relaxed(icr, aq->regs + QSPI_WICR);
> +		writel_relaxed(ifr, aq->regs + QSPI_IFR);
> +	} else {
> +		if (op->data.dir == SPI_MEM_DATA_OUT)
> +			ifr |= QSPI_IFR_SAMA5D2_WRITE_TRSFR;
> +
> +		/* Set QSPI Instruction Frame registers */
> +		writel_relaxed(iar, aq->regs + QSPI_IAR);
> +		writel_relaxed(icr, aq->regs + QSPI_ICR);
> +		writel_relaxed(ifr, aq->regs + QSPI_IFR);
> +	}
> +
> +	return 0;
> +}
> +
> +static int atmel_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
> +{
> +	struct atmel_qspi *aq = spi_controller_get_devdata(mem->spi->master);
> +	u32 sr, offset;
> +	int err;
> +
> +	err = atmel_qspi_set_cfg(aq, op, &offset);
> +	if (err)
> +		return err;
>  
>  	/* Skip to the final steps if there is no data */
>  	if (op->data.nbytes) {
> @@ -290,11 +339,11 @@ static int atmel_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>  
>  		/* Send/Receive data */
>  		if (op->data.dir == SPI_MEM_DATA_IN)
> -			_memcpy_fromio(op->data.buf.in,
> -				aq->mem + iar, op->data.nbytes);
> +			_memcpy_fromio(op->data.buf.in, aq->mem + offset,
> +				       op->data.nbytes);
>  		else
> -			_memcpy_toio(aq->mem + iar,
> -				op->data.buf.out, op->data.nbytes);
> +			_memcpy_toio(aq->mem + offset, op->data.buf.out,
> +				     op->data.nbytes);
>  
>  		/* Release the chip-select */
>  		writel_relaxed(QSPI_CR_LASTXFER, aq->regs + QSPI_CR);
> @@ -450,28 +499,55 @@ static int atmel_qspi_probe(struct platform_device *pdev)
>  		goto exit;
>  	}
>  
> +	aq->caps = of_device_get_match_data(&pdev->dev);
> +	if (!aq->caps) {
> +		dev_err(&pdev->dev, "Could not retrieve QSPI caps\n");
> +		err = -EINVAL;
> +		goto exit;
> +	}
> +
> +	if (aq->caps->has_qspick) {
> +		/* Get the QSPI system clock */
> +		aq->qspick = devm_clk_get(&pdev->dev, "qspick");
> +		if (IS_ERR(aq->qspick)) {
> +			dev_err(&pdev->dev, "missing system clock\n");
> +			err = PTR_ERR(aq->qspick);
> +			goto disable_pclk;
> +		}
> +
> +		/* Enable the QSPI system clock */
> +		err = clk_prepare_enable(aq->qspick);
> +		if (err) {
> +			dev_err(&pdev->dev,
> +				"failed to enable the QSPI system clock\n");
> +			goto disable_pclk;
> +		}
> +	}
> +
>  	/* Request the IRQ */
>  	irq = platform_get_irq(pdev, 0);
>  	if (irq < 0) {
>  		dev_err(&pdev->dev, "missing IRQ\n");
>  		err = irq;
> -		goto disable_pclk;
> +		goto disable_qspick;
>  	}
>  	err = devm_request_irq(&pdev->dev, irq, atmel_qspi_interrupt,
>  			       0, dev_name(&pdev->dev), aq);
>  	if (err)
> -		goto disable_pclk;
> +		goto disable_qspick;
>  
>  	err = atmel_qspi_init(aq);
>  	if (err)
> -		goto disable_pclk;
> +		goto disable_qspick;
>  
>  	err = spi_register_controller(ctrl);
>  	if (err)
> -		goto disable_pclk;
> +		goto disable_qspick;
>  
>  	return 0;
>  
> +disable_qspick:
> +	clk_disable_unprepare(aq->qspick);
>  disable_pclk:
>  	clk_disable_unprepare(aq->pclk);
>  exit:
> @@ -487,6 +563,7 @@ static int atmel_qspi_remove(struct platform_device *pdev)
>  
>  	spi_unregister_controller(ctrl);
>  	writel_relaxed(QSPI_CR_QSPIDIS, aq->regs + QSPI_CR);
> +	clk_disable_unprepare(aq->qspick);
>  	clk_disable_unprepare(aq->pclk);
>  	return 0;
>  }
> @@ -495,6 +572,7 @@ static int __maybe_unused atmel_qspi_suspend(struct device *dev)
>  {
>  	struct atmel_qspi *aq = dev_get_drvdata(dev);
>  
> +	clk_disable_unprepare(aq->qspick);
>  	clk_disable_unprepare(aq->pclk);
>  
>  	return 0;
> @@ -505,6 +583,7 @@ static int __maybe_unused atmel_qspi_resume(struct device *dev)
>  	struct atmel_qspi *aq = dev_get_drvdata(dev);
>  
>  	clk_prepare_enable(aq->pclk);
> +	clk_prepare_enable(aq->qspick);
>  
>  	return atmel_qspi_init(aq);
>  }
> @@ -512,8 +591,22 @@ static int __maybe_unused atmel_qspi_resume(struct device *dev)
>  static SIMPLE_DEV_PM_OPS(atmel_qspi_pm_ops, atmel_qspi_suspend,
>  			 atmel_qspi_resume);
>  
> +static const struct atmel_qspi_caps atmel_sama5d2_qspi_caps = {};
> +
> +static const struct atmel_qspi_caps atmel_sam9x60_qspi_caps = {
> +	.has_qspick = true,
> +	.has_ricr = true,
> +};
> +
>  static const struct of_device_id atmel_qspi_dt_ids[] = {
> -	{ .compatible = "atmel,sama5d2-qspi" },
> +	{
> +		.compatible = "atmel,sama5d2-qspi",
> +		.data = &atmel_sama5d2_qspi_caps,
> +	},
> +	{
> +		.compatible = "microchip,sam9x60-qspi",
> +		.data = &atmel_sam9x60_qspi_caps,
> +	},
>  	{ /* sentinel */ }
>  };
>  

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