Subject: [PATCH linux-next 5/5] mtd: atmel-quadspi: add driver for Atmel QSPI controller

From: [email-masked] (Nicolas Ferre)
Date: Fri, 11 Dec 2015 15:50:15 +0100

Le 07/12/2015 15:09, Cyrille Pitchen a ?crit :
> This driver add support to the new Atmel QSPI controller embedded into
> sama5d2x SoCs. It expects a NOR memory to be connected to the QSPI
> controller.
> 
> Signed-off-by: Cyrille Pitchen <[email-masked]>

Brian,

This driver has been maturing for months and my only goal is to keep on
supporting it.
As I already gave my Ack this summer, here is it now for sure:

Acked-by: Nicolas Ferre <[email-masked]>

I recall that Marek gave his as well and might also agree with the
changes and re-iterate his support.

Together with the current work of Cyrille on the spi-nor Quad SPI
support ("[PATCH linux-next 0/4] mtd: spi-nor: fix Quad SPI memory
support"), I have the feeling that this driver deserves an inclusion in
linux-next.
The infrastructure put in place and then used by this driver will
certainly help other developers to build their driver on top. I had the
impression that at least Marek was considering to use this for his
Cadence driver:

His quote from mid-September:
"
Are there any news on this patch series? I'd like to use that for my own
QSPI driver (the Cadence one), so I'd like to check on the status. Are you
still working on this please ?
"

Can we find a way to give this work even more exposure and consider at
least the spi-nor and m25p80 parts mentioned just above for mainline
inclusion?

Best regards,

> ---
>  drivers/mtd/spi-nor/Kconfig         |   8 +
>  drivers/mtd/spi-nor/Makefile        |   3 +-
>  drivers/mtd/spi-nor/atmel-quadspi.c | 877 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 887 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/mtd/spi-nor/atmel-quadspi.c
> 
> diff --git a/drivers/mtd/spi-nor/Kconfig b/drivers/mtd/spi-nor/Kconfig
> index 0dc927540b3d..15f45dbbfe0d 100644
> --- a/drivers/mtd/spi-nor/Kconfig
> +++ b/drivers/mtd/spi-nor/Kconfig
> @@ -37,6 +37,14 @@ config SPI_FSL_QUADSPI
>  	  This controller does not support generic SPI. It only supports
>  	  SPI NOR.
>  
> +config SPI_ATMEL_QUADSPI
> +	tristate "Atmel Quad SPI Controller"
> +	depends on OF && HAS_DMA && (ARCH_AT91 || COMPILE_TEST)
> +	help
> +	  This enables support for the Quad SPI controller in master mode.
> +	  This driver does not support generic SPI. The implementation only
> +	  supports SPI NOR.
> +
>  config SPI_NXP_SPIFI
>  	tristate "NXP SPI Flash Interface (SPIFI)"
>  	depends on OF && (ARCH_LPC18XX || COMPILE_TEST)
> diff --git a/drivers/mtd/spi-nor/Makefile b/drivers/mtd/spi-nor/Makefile
> index 0bf3a7f81675..0cbed0e4ae8c 100644
> --- a/drivers/mtd/spi-nor/Makefile
> +++ b/drivers/mtd/spi-nor/Makefile
> @@ -1,4 +1,5 @@
>  obj-$(CONFIG_MTD_SPI_NOR)	+= spi-nor.o
>  obj-$(CONFIG_SPI_FSL_QUADSPI)	+= fsl-quadspi.o
> -obj-$(CONFIG_MTD_MT81xx_NOR)    += mtk-quadspi.o
> +obj-$(CONFIG_MTD_MT81xx_NOR)	+= mtk-quadspi.o
> +obj-$(CONFIG_SPI_ATMEL_QUADSPI)	+= atmel-quadspi.o
>  obj-$(CONFIG_SPI_NXP_SPIFI)	+= nxp-spifi.o
> diff --git a/drivers/mtd/spi-nor/atmel-quadspi.c b/drivers/mtd/spi-nor/atmel-quadspi.c
> new file mode 100644
> index 000000000000..bdebfdc92842
> --- /dev/null
> +++ b/drivers/mtd/spi-nor/atmel-quadspi.c
> @@ -0,0 +1,877 @@
> +/*
> + * Driver for Atmel QSPI Controller
> + *
> + * Copyright (C) 2015 Atmel Corporation
> + *
> + * Author: Cyrille Pitchen <[email-masked]>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + *
> + * This driver is based on drivers/mtd/spi-nor/fsl-quadspi.c from Freescale.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/clk.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/delay.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/dmaengine.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/partitions.h>
> +#include <linux/mtd/spi-nor.h>
> +#include <linux/platform_data/atmel.h>
> +#include <linux/platform_data/dma-atmel.h>
> +#include <linux/of.h>
> +
> +#include <linux/io.h>
> +#include <linux/gpio.h>
> +#include <linux/pinctrl/consumer.h>
> +
> +/* QSPI register offsets */
> +#define QSPI_CR      0x0000  /* Control Register */
> +#define QSPI_MR      0x0004  /* Mode Register */
> +#define QSPI_RD      0x0008  /* Receive Data Register */
> +#define QSPI_TD      0x000c  /* Transmit Data Register */
> +#define QSPI_SR      0x0010  /* Status Register */
> +#define QSPI_IER     0x0014  /* Interrupt Enable Register */
> +#define QSPI_IDR     0x0018  /* Interrupt Disable Register */
> +#define QSPI_IMR     0x001c  /* Interrupt Mask Register */
> +#define QSPI_SCR     0x0020  /* Serial Clock Register */
> +
> +#define QSPI_IAR     0x0030  /* Instruction Address Register */
> +#define QSPI_ICR     0x0034  /* Instruction Code Register */
> +#define QSPI_IFR     0x0038  /* Instruction Frame Register */
> +
> +#define QSPI_SMR     0x0040  /* Scrambling Mode Register */
> +#define QSPI_SKR     0x0044  /* Scrambling Key Register */
> +
> +#define QSPI_WPMR    0x00E4  /* Write Protection Mode Register */
> +#define QSPI_WPSR    0x00E8  /* Write Protection Status Register */
> +
> +#define QSPI_VERSION 0x00FC  /* Version Register */
> +
> +
> +/* Bitfields in QSPI_CR (Control Register) */
> +#define QSPI_CR_QSPIEN                  BIT(0)
> +#define QSPI_CR_QSPIDIS                 BIT(1)
> +#define QSPI_CR_SWRST                   BIT(7)
> +#define QSPI_CR_LASTXFER                BIT(24)
> +
> +/* Bitfields in QSPI_MR (Mode Register) */
> +#define QSPI_MR_SSM                     BIT(0)
> +#define QSPI_MR_LLB                     BIT(1)
> +#define QSPI_MR_WDRBT                   BIT(2)
> +#define QSPI_MR_SMRM                    BIT(3)
> +#define QSPI_MR_CSMODE_MASK             GENMASK(5, 4)
> +#define QSPI_MR_CSMODE_NOT_RELOADED     (0 << 4)
> +#define QSPI_MR_CSMODE_LASTXFER         (1 << 4)
> +#define QSPI_MR_CSMODE_SYSTEMATICALLY   (2 << 4)
> +#define QSPI_MR_NBBITS_MASK             GENMASK(11, 8)
> +#define QSPI_MR_NBBITS(n)               ((((n) - 8) << 8) & QSPI_MR_NBBITS_MASK)
> +#define QSPI_MR_DLYBCT_MASK             GENMASK(23, 16)
> +#define QSPI_MR_DLYBCT(n)               (((n) << 16) & QSPI_MR_DLYBCT_MASK)
> +#define QSPI_MR_DLYCS_MASK              GENMASK(31, 24)
> +#define QSPI_MR_DLYCS(n)                (((n) << 24) & QSPI_MR_DLYCS_MASK)
> +
> +/* Bitfields in QSPI_SR/QSPI_IER/QSPI_IDR/QSPI_IMR  */
> +#define QSPI_SR_RDRF                    BIT(0)
> +#define QSPI_SR_TDRE                    BIT(1)
> +#define QSPI_SR_TXEMPTY                 BIT(2)
> +#define QSPI_SR_OVRES                   BIT(3)
> +#define QSPI_SR_CSR                     BIT(8)
> +#define QSPI_SR_CSS                     BIT(9)
> +#define QSPI_SR_INSTRE                  BIT(10)
> +#define QSPI_SR_QSPIENS                 BIT(24)
> +
> +/* Bitfields in QSPI_SCR (Serial Clock Register) */
> +#define QSPI_SCR_CPOL                   BIT(0)
> +#define QSPI_SCR_CPHA                   BIT(1)
> +#define QSPI_SCR_SCBR_MASK              GENMASK(15, 8)
> +#define QSPI_SCR_SCBR(n)                (((n) << 8) & QSPI_SCR_SCBR_MASK)
> +#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) */
> +#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)
> +#define QSPI_ICR_OPT(opt)               (((opt) << 16) & QSPI_ICR_OPT_MASK)
> +
> +/* Bitfields in QSPI_IFR (Instruction Frame Register) */
> +#define QSPI_IFR_WIDTH_MASK             GENMASK(2, 0)
> +#define QSPI_IFR_WIDTH_SINGLE_BIT_SPI   (0 << 0)
> +#define QSPI_IFR_WIDTH_DUAL_OUTPUT      (1 << 0)
> +#define QSPI_IFR_WIDTH_QUAD_OUTPUT      (2 << 0)
> +#define QSPI_IFR_WIDTH_DUAL_IO          (3 << 0)
> +#define QSPI_IFR_WIDTH_QUAD_IO          (4 << 0)
> +#define QSPI_IFR_WIDTH_DUAL_CMD         (5 << 0)
> +#define QSPI_IFR_WIDTH_QUAD_CMD         (6 << 0)
> +#define QSPI_IFR_INSTEN                 BIT(4)
> +#define QSPI_IFR_ADDREN                 BIT(5)
> +#define QSPI_IFR_OPTEN                  BIT(6)
> +#define QSPI_IFR_DATAEN                 BIT(7)
> +#define QSPI_IFR_OPTL_MASK              GENMASK(9, 8)
> +#define QSPI_IFR_OPTL_1BIT              (0 << 8)
> +#define QSPI_IFR_OPTL_2BIT              (1 << 8)
> +#define QSPI_IFR_OPTL_4BIT              (2 << 8)
> +#define QSPI_IFR_OPTL_8BIT              (3 << 8)
> +#define QSPI_IFR_ADDRL                  BIT(10)
> +#define QSPI_IFR_TFRTYP_MASK            GENMASK(13, 12)
> +#define QSPI_IFR_TFRTYP_TRSFR_READ      (0 << 12)
> +#define QSPI_IFR_TFRTYP_TRSFR_READ_MEM  (1 << 12)
> +#define QSPI_IFR_TFRTYP_TRSFR_WRITE     (2 << 12)
> +#define QSPI_IFR_TFRTYP_TRSFR_WRITE_MEM (3 << 13)
> +#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)
> +
> +/* Bitfields in QSPI_SMR (Scrambling Mode Register) */
> +#define QSPI_SMR_SCREN                  BIT(0)
> +#define QSPI_SMR_RVDIS                  BIT(1)
> +
> +/* Bitfields in QSPI_WPMR (Write Protection Mode Register) */
> +#define QSPI_WPMR_WPEN                  BIT(0)
> +#define QSPI_WPMR_WPKEY_MASK            GENMASK(31, 8)
> +#define QSPI_WPMR_WPKEY(wpkey)          (((wpkey) << 8) & QSPI_WPMR_WPKEY_MASK)
> +
> +/* Bitfields in QSPI_WPSR (Write Protection Status Register) */
> +#define QSPI_WPSR_WPVS                  BIT(0)
> +#define QSPI_WPSR_WPVSRC_MASK           GENMASK(15, 8)
> +#define QSPI_WPSR_WPVSRC(src)           (((src) << 8) & QSPI_WPSR_WPVSRC)
> +
> +
> +struct atmel_qspi {
> +	void __iomem		*regs;
> +	void __iomem		*mem;
> +	dma_addr_t		phys_addr;
> +	struct dma_chan		*chan;
> +	struct clk		*clk;
> +	struct platform_device	*pdev;
> +	u32			pending;
> +
> +	struct spi_nor		nor;
> +	u32			clk_rate;
> +	struct completion	cmd_completion;
> +	struct completion	dma_completion;
> +
> +#ifdef DEBUG
> +	u8			last_instruction;
> +#endif
> +};
> +
> +struct atmel_qspi_command {
> +	u32	ifr;
> +	union {
> +		struct {
> +			u32	instruction:1;
> +			u32	address:3;
> +			u32	mode:1;
> +			u32	dummy:1;
> +			u32	data:1;
> +			u32	dma:1;
> +			u32	reserved:24;
> +		}		bits;
> +		u32	word;
> +	}	enable;
> +	u8	instruction;
> +	u8	mode;
> +	u8	num_mode_cycles;
> +	u8	num_dummy_cycles;
> +	u32	address;
> +
> +	size_t		buf_len;
> +	const void	*tx_buf;
> +	void		*rx_buf;
> +};
> +
> +/* Register access functions */
> +static inline u32 qspi_readl(struct atmel_qspi *aq, u32 reg)
> +{
> +	return readl_relaxed(aq->regs + reg);
> +}
> +
> +static inline void qspi_writel(struct atmel_qspi *aq, u32 reg, u32 value)
> +{
> +	writel_relaxed(value, aq->regs + reg);
> +}
> +
> +
> +#define QSPI_DMA_THRESHOLD	32
> +
> +static void atmel_qspi_dma_callback(void *arg)
> +{
> +	struct completion *dma_completion = arg;
> +
> +	complete(dma_completion);
> +}
> +
> +static int atmel_qspi_run_dma_transfer(struct atmel_qspi *aq,
> +				       const struct atmel_qspi_command *cmd)
> +{
> +	u32 offset = (cmd->enable.bits.address) ? cmd->address : 0;
> +	struct dma_chan *chan = aq->chan;
> +	struct device *dev = &aq->pdev->dev;
> +	enum dma_data_direction direction;
> +	dma_addr_t phys_addr, dst, src;
> +	struct dma_async_tx_descriptor *desc;
> +	dma_cookie_t cookie;
> +	int err = 0;
> +
> +	if (cmd->tx_buf) {
> +		direction = DMA_TO_DEVICE;
> +		phys_addr = dma_map_single(dev, (void *)cmd->tx_buf,
> +					   cmd->buf_len, direction);
> +		src = phys_addr;
> +		dst = aq->phys_addr + offset;
> +	} else {
> +		direction = DMA_FROM_DEVICE;
> +		phys_addr = dma_map_single(dev, (void *)cmd->rx_buf,
> +					   cmd->buf_len, direction);
> +		src = aq->phys_addr + offset;
> +		dst = phys_addr;
> +	}
> +	if (dma_mapping_error(dev, phys_addr))
> +		return -ENOMEM;
> +
> +	desc = chan->device->device_prep_dma_memcpy(chan, dst, src,
> +						    cmd->buf_len,
> +						    DMA_PREP_INTERRUPT);
> +	if (!desc) {
> +		err = -ENOMEM;
> +		goto unmap_single;
> +	}
> +
> +	reinit_completion(&aq->dma_completion);
> +	desc->callback = atmel_qspi_dma_callback;
> +	desc->callback_param = &aq->dma_completion;
> +	cookie = dmaengine_submit(desc);
> +	err = dma_submit_error(cookie);
> +	if (err)
> +		goto unmap_single;
> +	dma_async_issue_pending(chan);
> +
> +	if (!wait_for_completion_timeout(&aq->dma_completion,
> +					 msecs_to_jiffies(1000)))
> +		err = -ETIMEDOUT;
> +
> +	if (dma_async_is_tx_complete(chan, cookie, NULL, NULL) != DMA_COMPLETE)
> +		err = -ETIMEDOUT;
> +
> +	if (err)
> +		dmaengine_terminate_all(chan);
> +unmap_single:
> +	dma_unmap_single(dev, phys_addr, cmd->buf_len, direction);
> +
> +	return err;
> +}
> +
> +static int atmel_qspi_run_transfer(struct atmel_qspi *aq,
> +				   const struct atmel_qspi_command *cmd)
> +{
> +	void __iomem *ahb_mem;
> +
> +	/* First try a DMA transfer */
> +	if (aq->chan && cmd->enable.bits.dma &&
> +	    cmd->buf_len >= QSPI_DMA_THRESHOLD)
> +		return atmel_qspi_run_dma_transfer(aq, cmd);
> +
> +	/* Then fallback to a PIO transfer (memcpy() DOES NOT work!) */
> +	ahb_mem = aq->mem;
> +	if (cmd->enable.bits.address)
> +		ahb_mem += cmd->address;
> +	if (cmd->tx_buf)
> +		_memcpy_toio(ahb_mem, cmd->tx_buf, cmd->buf_len);
> +	else
> +		_memcpy_fromio(cmd->rx_buf, ahb_mem, cmd->buf_len);
> +
> +	return 0;
> +}
> +
> +#ifdef DEBUG
> +static void atmel_qspi_debug_command(struct atmel_qspi *aq,
> +				     const struct atmel_qspi_command *cmd)
> +{
> +	u8 cmd_buf[SPI_NOR_MAX_CMD_SIZE];
> +	size_t len = 0;
> +	int i;
> +
> +	if (cmd->enable.bits.instruction) {
> +		if (aq->last_instruction == cmd->instruction)
> +			return;
> +		aq->last_instruction = cmd->instruction;
> +	}
> +
> +	if (cmd->enable.bits.instruction)
> +		cmd_buf[len++] = cmd->instruction;
> +
> +	for (i = cmd->enable.bits.address-1; i >= 0; --i)
> +		cmd_buf[len++] = (cmd->address >> (i << 3)) & 0xff;
> +
> +	if (cmd->enable.bits.mode)
> +		cmd_buf[len++] = cmd->mode;
> +
> +	if (cmd->enable.bits.dummy) {
> +		int num = cmd->num_dummy_cycles;
> +
> +		switch (cmd->ifr & QSPI_IFR_WIDTH_MASK) {
> +		case QSPI_IFR_WIDTH_SINGLE_BIT_SPI:
> +		case QSPI_IFR_WIDTH_DUAL_OUTPUT:
> +		case QSPI_IFR_WIDTH_QUAD_OUTPUT:
> +			num >>= 3;
> +			break;
> +		case QSPI_IFR_WIDTH_DUAL_IO:
> +		case QSPI_IFR_WIDTH_DUAL_CMD:
> +			num >>= 2;
> +			break;
> +		case QSPI_IFR_WIDTH_QUAD_IO:
> +		case QSPI_IFR_WIDTH_QUAD_CMD:
> +			num >>= 1;
> +			break;
> +		default:
> +			return;
> +		}
> +
> +		for (i = 0; i < num; ++i)
> +			cmd_buf[len++] = 0;
> +	}
> +
> +	/* Dump the SPI command */
> +	print_hex_dump(KERN_DEBUG, "qspi cmd: ", DUMP_PREFIX_NONE,
> +		       32, 1, cmd_buf, len, false);
> +
> +#ifdef VERBOSE_DEBUG
> +	/* If verbose debug is enabled, also dump the TX data */
> +	if (cmd->enable.bits.data && cmd->tx_buf)
> +		print_hex_dump(KERN_DEBUG, "qspi tx : ", DUMP_PREFIX_NONE,
> +			       32, 1, cmd->tx_buf, cmd->buf_len, false);
> +#endif
> +}
> +#else
> +#define atmel_qspi_debug_command(aq, cmd)
> +#endif
> +
> +static int atmel_qspi_run_command(struct atmel_qspi *aq,
> +				  const struct atmel_qspi_command *cmd)
> +{
> +	u32 iar, icr, ifr, sr;
> +	int err = 0;
> +
> +	iar = 0;
> +	icr = 0;
> +	ifr = cmd->ifr;
> +
> +	/* Compute instruction parameters */
> +	if (cmd->enable.bits.instruction) {
> +		icr |= QSPI_ICR_INST(cmd->instruction);
> +		ifr |= QSPI_IFR_INSTEN;
> +	}
> +
> +	/* Compute address parameters */
> +	switch (cmd->enable.bits.address) {
> +	case 4:
> +		ifr |= QSPI_IFR_ADDRL;
> +		/* fall through to the 24bit (3 byte) address case. */
> +	case 3:
> +		iar = (cmd->enable.bits.data) ? 0 : cmd->address;
> +		ifr |= QSPI_IFR_ADDREN;
> +		break;
> +	case 0:
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	/* Compute option parameters */
> +	if (cmd->enable.bits.mode && cmd->num_mode_cycles) {
> +		u32 mode_cycle_bits, mode_bits;
> +
> +		icr |= QSPI_ICR_OPT(cmd->mode);
> +		ifr |= QSPI_IFR_OPTEN;
> +
> +		switch (ifr & QSPI_IFR_WIDTH_MASK) {
> +		case QSPI_IFR_WIDTH_SINGLE_BIT_SPI:
> +		case QSPI_IFR_WIDTH_DUAL_OUTPUT:
> +		case QSPI_IFR_WIDTH_QUAD_OUTPUT:
> +			mode_cycle_bits = 1;
> +			break;
> +		case QSPI_IFR_WIDTH_DUAL_IO:
> +		case QSPI_IFR_WIDTH_DUAL_CMD:
> +			mode_cycle_bits = 2;
> +			break;
> +		case QSPI_IFR_WIDTH_QUAD_IO:
> +		case QSPI_IFR_WIDTH_QUAD_CMD:
> +			mode_cycle_bits = 4;
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +
> +		mode_bits = cmd->num_mode_cycles * mode_cycle_bits;
> +		switch (mode_bits) {
> +		case 1:
> +			ifr |= QSPI_IFR_OPTL_1BIT;
> +			break;
> +
> +		case 2:
> +			ifr |= QSPI_IFR_OPTL_2BIT;
> +			break;
> +
> +		case 4:
> +			ifr |= QSPI_IFR_OPTL_4BIT;
> +			break;
> +
> +		case 8:
> +			ifr |= QSPI_IFR_OPTL_8BIT;
> +			break;
> +
> +		default:
> +			return -EINVAL;
> +		}
> +	}
> +
> +	/* Set number of dummy cycles */
> +	if (cmd->enable.bits.dummy)
> +		ifr |= QSPI_IFR_NBDUM(cmd->num_dummy_cycles);
> +
> +	/* Set data enable */
> +	if (cmd->enable.bits.data) {
> +		ifr |= QSPI_IFR_DATAEN;
> +
> +		/* Special case for Continuous Read Mode */
> +		if (!cmd->tx_buf && !cmd->rx_buf)
> +			ifr |= QSPI_IFR_CRM;
> +	}
> +
> +	/* Set QSPI Instruction Frame registers */
> +	atmel_qspi_debug_command(aq, cmd);
> +	qspi_writel(aq, QSPI_IAR, iar);
> +	qspi_writel(aq, QSPI_ICR, icr);
> +	qspi_writel(aq, QSPI_IFR, ifr);
> +
> +	/* Skip to the final steps if there is no data */
> +	if (!cmd->enable.bits.data)
> +		goto no_data;
> +
> +	/* Dummy read of QSPI_IFR to synchronize APB and AHB accesses */
> +	(void)qspi_readl(aq, QSPI_IFR);
> +
> +	/* Stop here for continuous read */
> +	if (!cmd->tx_buf && !cmd->rx_buf)
> +		return 0;
> +	/* Send/Receive data */
> +	err = atmel_qspi_run_transfer(aq, cmd);
> +
> +	/* Release the chip-select */
> +	qspi_writel(aq, QSPI_CR, QSPI_CR_LASTXFER);
> +
> +	if (err)
> +		return err;
> +
> +#if defined(DEBUG) && defined(VERBOSE_DEBUG)
> +	/*
> +	 * If verbose debug is enabled, also dump the RX data in addition to
> +	 * the SPI command previously dumped by atmel_qspi_debug_command()
> +	 */
> +	if (cmd->rx_buf)
> +		print_hex_dump(KERN_DEBUG, "qspi rx : ", DUMP_PREFIX_NONE,
> +			       32, 1, cmd->rx_buf, cmd->buf_len, false);
> +#endif
> +no_data:
> +	/* Poll INSTRuction End status */
> +	sr = qspi_readl(aq, QSPI_SR);
> +	if (sr & QSPI_SR_INSTRE)
> +		return err;
> +
> +	/* Wait for INSTRuction End interrupt */
> +	reinit_completion(&aq->cmd_completion);
> +	aq->pending = 0;
> +	qspi_writel(aq, QSPI_IER, QSPI_SR_INSTRE);
> +	if (!wait_for_completion_timeout(&aq->cmd_completion,
> +					 msecs_to_jiffies(1000)))
> +		err = -ETIMEDOUT;
> +	qspi_writel(aq, QSPI_IDR, QSPI_SR_INSTRE);
> +
> +	return err;
> +}
> +
> +static int atmel_qspi_command_set_ifr(struct atmel_qspi_command *cmd,
> +				      u32 ifr_tfrtyp,
> +				      enum spi_protocol proto)
> +{
> +	cmd->ifr = ifr_tfrtyp;
> +
> +	switch (proto) {
> +	case SPI_PROTO_1_1_1:
> +		cmd->ifr |= QSPI_IFR_WIDTH_SINGLE_BIT_SPI;
> +		break;
> +	case SPI_PROTO_1_1_2:
> +		cmd->ifr |= QSPI_IFR_WIDTH_DUAL_OUTPUT;
> +		break;
> +	case SPI_PROTO_1_1_4:
> +		cmd->ifr |= QSPI_IFR_WIDTH_QUAD_OUTPUT;
> +		break;
> +	case SPI_PROTO_1_2_2:
> +		cmd->ifr |= QSPI_IFR_WIDTH_DUAL_IO;
> +		break;
> +	case SPI_PROTO_1_4_4:
> +		cmd->ifr |= QSPI_IFR_WIDTH_QUAD_IO;
> +		break;
> +	case SPI_PROTO_2_2_2:
> +		cmd->ifr |= QSPI_IFR_WIDTH_DUAL_CMD;
> +		break;
> +	case SPI_PROTO_4_4_4:
> +		cmd->ifr |= QSPI_IFR_WIDTH_QUAD_CMD;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int atmel_qspi_read_reg(struct spi_nor *nor, u8 opcode,
> +			       u8 *buf, int len)
> +{
> +	struct atmel_qspi *aq = nor->priv;
> +	struct atmel_qspi_command cmd;
> +	int ret;
> +
> +	memset(&cmd, 0, sizeof(cmd));
> +	cmd.enable.bits.instruction = 1;
> +	cmd.enable.bits.data = 1;
> +	cmd.instruction = opcode;
> +	cmd.rx_buf = buf;
> +	cmd.buf_len = len;
> +
> +	ret = atmel_qspi_command_set_ifr(&cmd,
> +					 QSPI_IFR_TFRTYP_TRSFR_READ,
> +					 nor->reg_proto);
> +	if (ret)
> +		return ret;
> +
> +	return atmel_qspi_run_command(aq, &cmd);
> +}
> +
> +static int atmel_qspi_write_reg(struct spi_nor *nor, u8 opcode,
> +				u8 *buf, int len)
> +{
> +	struct atmel_qspi *aq = nor->priv;
> +	struct atmel_qspi_command cmd;
> +	int ret;
> +
> +	memset(&cmd, 0, sizeof(cmd));
> +	cmd.enable.bits.instruction = 1;
> +	cmd.enable.bits.data = (buf != NULL && len > 0);
> +	cmd.instruction = opcode;
> +	cmd.tx_buf = buf;
> +	cmd.buf_len = len;
> +
> +	ret = atmel_qspi_command_set_ifr(&cmd,
> +					 QSPI_IFR_TFRTYP_TRSFR_WRITE,
> +					 nor->reg_proto);
> +	if (ret)
> +		return ret;
> +
> +	return atmel_qspi_run_command(aq, &cmd);
> +}
> +
> +static void atmel_qspi_write(struct spi_nor *nor, loff_t to, size_t len,
> +			     size_t *retlen, const u_char *write_buf)
> +{
> +	struct atmel_qspi *aq = nor->priv;
> +	struct atmel_qspi_command cmd;
> +
> +	memset(&cmd, 0, sizeof(cmd));
> +	cmd.enable.bits.instruction = 1;
> +	cmd.enable.bits.address = nor->addr_width;
> +	cmd.enable.bits.data = 1;
> +	cmd.enable.bits.dma = 1;
> +	cmd.instruction = nor->program_opcode;
> +	cmd.address = (u32)to;
> +	cmd.tx_buf = write_buf;
> +	cmd.buf_len = len;
> +
> +	if (atmel_qspi_command_set_ifr(&cmd,
> +				       QSPI_IFR_TFRTYP_TRSFR_WRITE_MEM,
> +				       nor->write_proto))
> +		return;
> +
> +	if (!atmel_qspi_run_command(aq, &cmd))
> +		*retlen += len;
> +}
> +
> +static int atmel_qspi_erase(struct spi_nor *nor, loff_t offs)
> +{
> +	struct atmel_qspi *aq = nor->priv;
> +	struct atmel_qspi_command cmd;
> +	int ret;
> +
> +	dev_dbg(nor->dev, "%dKiB at 0x%08x\n",
> +		nor->mtd.erasesize / 1024, (u32)offs);
> +
> +	memset(&cmd, 0, sizeof(cmd));
> +	cmd.enable.bits.instruction = 1;
> +	cmd.enable.bits.address = nor->addr_width;
> +	cmd.instruction = nor->erase_opcode;
> +	cmd.address = (u32)offs;
> +
> +	ret = atmel_qspi_command_set_ifr(&cmd,
> +					 QSPI_IFR_TFRTYP_TRSFR_WRITE,
> +					 nor->erase_proto);
> +	if (ret)
> +		return ret;
> +
> +	return atmel_qspi_run_command(aq, &cmd);
> +}
> +
> +static int atmel_qspi_read(struct spi_nor *nor, loff_t from, size_t len,
> +			   size_t *retlen, u_char *read_buf)
> +{
> +	struct atmel_qspi *aq = nor->priv;
> +	struct atmel_qspi_command cmd;
> +	int ret;
> +
> +	memset(&cmd, 0, sizeof(cmd));
> +	cmd.enable.bits.instruction = 1;
> +	cmd.enable.bits.address = nor->addr_width;
> +	cmd.enable.bits.dummy = (nor->read_dummy > 0);
> +	cmd.enable.bits.data = 1;
> +	cmd.enable.bits.dma = 1;
> +	cmd.instruction = nor->read_opcode;
> +	cmd.address = (u32)from;
> +	cmd.num_dummy_cycles = nor->read_dummy;
> +	cmd.rx_buf = read_buf;
> +	cmd.buf_len = len;
> +
> +	ret = atmel_qspi_command_set_ifr(&cmd,
> +					 QSPI_IFR_TFRTYP_TRSFR_READ_MEM,
> +					 nor->read_proto);
> +	if (ret)
> +		return ret;
> +
> +	ret = atmel_qspi_run_command(aq, &cmd);
> +	if (ret)
> +		return ret;
> +
> +	*retlen += len;
> +	return 0;
> +}
> +
> +static int atmel_qspi_init(struct atmel_qspi *aq)
> +{
> +	unsigned long src_rate;
> +	u32 mr, scr, scbr;
> +
> +	/* Reset the QSPI controller */
> +	qspi_writel(aq, QSPI_CR, QSPI_CR_SWRST);
> +
> +	/* Set the QSPI controller in Serial Memory Mode */
> +	mr = QSPI_MR_SSM | QSPI_MR_NBBITS(8);
> +	qspi_writel(aq, QSPI_MR, mr);
> +
> +	src_rate = clk_get_rate(aq->clk);
> +	if (!src_rate)
> +		return -EINVAL;
> +
> +	/* Compute the QSPI baudrate */
> +	scbr = DIV_ROUND_UP(src_rate, aq->clk_rate);
> +	if (scbr > 0)
> +		scbr--;
> +	scr = QSPI_SCR_SCBR(scbr);
> +	qspi_writel(aq, QSPI_SCR, scr);
> +
> +	/* Enable the QSPI controller */
> +	qspi_writel(aq, QSPI_CR, QSPI_CR_QSPIEN);
> +
> +	return 0;
> +}
> +
> +static irqreturn_t atmel_qspi_interrupt(int irq, void *dev_id)
> +{
> +	struct atmel_qspi *aq = (struct atmel_qspi *)dev_id;
> +	u32 status, mask, pending;
> +
> +	status = qspi_readl(aq, QSPI_SR);
> +	mask = qspi_readl(aq, QSPI_IMR);
> +	pending = status & mask;
> +
> +	if (!pending)
> +		return IRQ_NONE;
> +
> +	aq->pending |= pending;
> +	if (pending & QSPI_SR_INSTRE)
> +		complete(&aq->cmd_completion);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int atmel_qspi_probe(struct platform_device *pdev)
> +{
> +	struct device_node *child, *np = pdev->dev.of_node;
> +	struct atmel_qspi *aq;
> +	struct resource *res;
> +	dma_cap_mask_t mask;
> +	struct spi_nor *nor;
> +	struct mtd_info *mtd;
> +	int irq, err = 0;
> +
> +	if (of_get_child_count(np) != 1)
> +		return -ENODEV;
> +	child = of_get_next_child(np, NULL);
> +
> +	aq = devm_kzalloc(&pdev->dev, sizeof(*aq), GFP_KERNEL);
> +	if (!aq) {
> +		err = -ENOMEM;
> +		goto exit;
> +	}
> +
> +	platform_set_drvdata(pdev, aq);
> +	init_completion(&aq->cmd_completion);
> +	init_completion(&aq->dma_completion);
> +	aq->pdev = pdev;
> +
> +	/* Map the registers */
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi_base");
> +	aq->regs = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(aq->regs)) {
> +		dev_err(&pdev->dev, "missing registers\n");
> +		err = PTR_ERR(aq->regs);
> +		goto exit;
> +	}
> +
> +	/* Map the AHB memory */
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi_mmap");
> +	aq->mem = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(aq->mem)) {
> +		dev_err(&pdev->dev, "missing AHB memory\n");
> +		err = PTR_ERR(aq->regs);
> +		goto exit;
> +	}
> +	aq->phys_addr = (dma_addr_t)res->start;
> +
> +	/* Get the peripheral clock */
> +	aq->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(aq->clk)) {
> +		dev_err(&pdev->dev, "missing peripheral clock\n");
> +		err = PTR_ERR(aq->clk);
> +		goto exit;
> +	}
> +
> +	/* Enable the peripheral clock */
> +	err = clk_prepare_enable(aq->clk);
> +	if (err) {
> +		dev_err(&pdev->dev, "failed to enable the peripheral clock\n");
> +		goto exit;
> +	}
> +
> +	/* Request the IRQ */
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0) {
> +		dev_err(&pdev->dev, "missing IRQ\n");
> +		err = irq;
> +		goto disable_clk;
> +	}
> +	err = devm_request_irq(&pdev->dev, irq, atmel_qspi_interrupt,
> +			       0, dev_name(&pdev->dev), aq);
> +	if (err)
> +		goto disable_clk;
> +
> +	/* Try to get a DMA channel for memcpy() operation */
> +	dma_cap_zero(mask);
> +	dma_cap_set(DMA_MEMCPY, mask);
> +	aq->chan = dma_request_channel(mask, NULL, NULL);
> +	if (!aq->chan)
> +		dev_warn(&pdev->dev, "no available DMA channel\n");
> +
> +	/* Setup the spi-nor */
> +	nor = &aq->nor;
> +	mtd = &nor->mtd;
> +
> +	nor->dev = &pdev->dev;
> +	spi_nor_set_flash_node(nor, child);
> +	nor->priv = aq;
> +	mtd->priv = nor;
> +
> +	nor->read_reg = atmel_qspi_read_reg;
> +	nor->write_reg = atmel_qspi_write_reg;
> +	nor->read = atmel_qspi_read;
> +	nor->write = atmel_qspi_write;
> +	nor->erase = atmel_qspi_erase;
> +
> +	err = of_property_read_u32(child, "spi-max-frequency", &aq->clk_rate);
> +	if (err < 0)
> +		goto release_channel;
> +
> +	err = atmel_qspi_init(aq);
> +	if (err)
> +		goto release_channel;
> +
> +	err = spi_nor_scan(nor, NULL, SPI_NOR_QUAD);
> +	if (err)
> +		goto release_channel;
> +
> +	err = mtd_device_register(mtd, NULL, 0);
> +	if (err)
> +		goto release_channel;
> +
> +	of_node_put(child);
> +
> +	return 0;
> +
> +release_channel:
> +	if (aq->chan)
> +		dma_release_channel(aq->chan);
> +disable_clk:
> +	clk_disable_unprepare(aq->clk);
> +exit:
> +	of_node_put(child);
> +
> +	return err;
> +}
> +
> +static int atmel_qspi_remove(struct platform_device *pdev)
> +{
> +	struct atmel_qspi *aq = platform_get_drvdata(pdev);
> +
> +	mtd_device_unregister(&aq->nor.mtd);
> +	qspi_writel(aq, QSPI_CR, QSPI_CR_QSPIDIS);
> +	if (aq->chan)
> +		dma_release_channel(aq->chan);
> +	clk_disable_unprepare(aq->clk);
> +	return 0;
> +}
> +
> +
> +static const struct of_device_id atmel_qspi_dt_ids[] = {
> +	{ .compatible = "atmel,sama5d2-qspi" },
> +	{ /* sentinel */ }
> +};
> +
> +MODULE_DEVICE_TABLE(of, atmel_qspi_dt_ids);
> +
> +static struct platform_driver atmel_qspi_driver = {
> +	.driver = {
> +		.name	= "atmel_qspi",
> +		.of_match_table	= atmel_qspi_dt_ids,
> +	},
> +	.probe		= atmel_qspi_probe,
> +	.remove		= atmel_qspi_remove,
> +};
> +module_platform_driver(atmel_qspi_driver);
> +
> +MODULE_AUTHOR("Cyrille Pitchen <[email-masked]>");
> +MODULE_DESCRIPTION("Atmel QSPI Controller driver");
> +MODULE_LICENSE("GPL v2");
> 

-- 
Nicolas Ferre