RE: [PATCH v5 1/5] spi: spi-mem: Add driver for NXP FlexSPI controller

[Yogesh Narayan Gaur <yogeshnarayan.gaur@nxp.com>]

Hi Frieder,

Thanks for the review. Please find my comments inline.

> -----Original Message-----
> From: Schrempf Frieder [mailto:frieder.schrempf@kontron.de]
> Sent: Thursday, December 6, 2018 2:53 PM
> To: Yogesh Narayan Gaur <yogeshnarayan.gaur@nxp.com>; linux-
> mtd@lists.infradead.org; boris.brezillon@bootlin.com; marek.vasut@gmail.com;
> broonie@kernel.org; linux-spi@vger.kernel.org; devicetree@vger.kernel.org
> Cc: robh@kernel.org; mark.rutland@arm.com; shawnguo@kernel.org; linux-
> arm-kernel@lists.infradead.org; computersforpeace@gmail.com; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH v5 1/5] spi: spi-mem: Add driver for NXP FlexSPI controller
> 
> Hi Yogesh,
> 
> I've had a closer look at your v5. See my comments below.
> 
> On 16.11.18 12:13, Yogesh Narayan Gaur wrote:
> > - Add driver for NXP FlexSPI host controller
> >
> > (0) What is the FlexSPI controller?
> >   FlexSPI is a flexsible SPI host controller which supports two SPI
> >   channels and up to 4 external devices. Each channel supports
> >   Single/Dual/Quad/Octal mode data transfer (1/2/4/8 bidirectional
> >   data lines) i.e. FlexSPI acts as an interface to external devices,
> >   maximum 4, each with up to 8 bidirectional data lines.
> >
> >   It uses new SPI memory interface of the SPI framework to issue
> >   flash memory operations to up to four connected flash
> >   devices (2 buses with 2 CS each).
> >
> > (1) Tested this driver with the mtd_debug and JFFS2 filesystem utility
> >   on NXP LX2160ARDB and LX2160AQDS targets.
> >   LX2160ARDB is having two NOR slave device connected on single bus A
> >   i.e. A0 and A1 (CS0 and CS1).
> >   LX2160AQDS is having two NOR slave device connected on separate buses
> >   one flash on A0 and second on B1 i.e. (CS0 and CS3).
> >   Verified this driver on following SPI NOR flashes:
> >      Micron, mt35xu512ab, [Read - 1 bit mode]
> >      Cypress, s25fl512s, [Read - 1/2/4 bit mode]
> >
> > Signed-off-by: Yogesh Gaur <yogeshnarayan.gaur@nxp.com>
> > ---
> > Changes for v5:
> > - Rebase on top of v4.20-rc2
> > - Modified fspi_readl_poll_tout() as per review comments
> > - Arrange header file in alphabetical order
> > - Removed usage of read()/write() function callback pointer
> > - Add support for 1 and 2 byte address length
> > - Change Frieder e-mail to new e-mail address Changes for v4:
> > - Incorporate Boris review comments
> >    * Use readl_poll_timeout() instead of busy looping.
> >    * Re-define register masking as per comment.
> >    * Drop fspi_devtype enum.
> > Changes for v3:
> > - Added endianness flag in platform specific structure instead of DTS.
> > - Modified nxp_fspi_read_ahb(), removed remapping code.
> > - Added Boris and Frieder as Author and provided reference of
> > spi-fsl-qspi.c Changes for v2:
> > - Incorporated Boris review comments.
> > - Remove dependency of driver over connected flash device size.
> > - Modified the logic to select requested CS.
> > - Remove SPI-Octal Macros.
> >
> >   drivers/spi/Kconfig        |   10 +
> >   drivers/spi/Makefile       |    1 +
> >   drivers/spi/spi-nxp-fspi.c | 1145
> ++++++++++++++++++++++++++++++++++++++++++++
> >   3 files changed, 1156 insertions(+)
> >   create mode 100644 drivers/spi/spi-nxp-fspi.c
> >
> > diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index
> > 7d3a5c9..36630a1 100644
> > --- a/drivers/spi/Kconfig
> > +++ b/drivers/spi/Kconfig
> > @@ -259,6 +259,16 @@ config SPI_FSL_LPSPI
> >   	help
> >   	  This enables Freescale i.MX LPSPI controllers in master mode.
> >
> > +config SPI_NXP_FLEXSPI
> > +	tristate "NXP Flex SPI controller"
> > +	depends on ARCH_LAYERSCAPE || HAS_IOMEM
> > +	help
> > +	  This enables support for the Flex SPI controller in master mode.
> > +	  Up to four slave devices can be connected on two buses with two
> > +	  chipselects each.
> > +	  This controller does not support generic SPI messages and only
> > +	  supports the high-level SPI memory interface.
> > +
> >   config SPI_GPIO
> >   	tristate "GPIO-based bitbanging SPI Master"
> >   	depends on GPIOLIB || COMPILE_TEST
> > diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index
> > 3575205..55fec5c 100644
> > --- a/drivers/spi/Makefile
> > +++ b/drivers/spi/Makefile
> > @@ -60,6 +60,7 @@ obj-$(CONFIG_SPI_MPC52xx)		+= spi-
> mpc52xx.o
> >   obj-$(CONFIG_SPI_MT65XX)                += spi-mt65xx.o
> >   obj-$(CONFIG_SPI_MXS)			+= spi-mxs.o
> >   obj-$(CONFIG_SPI_NUC900)		+= spi-nuc900.o
> > +obj-$(CONFIG_SPI_NXP_FLEXSPI)		+= spi-nxp-fspi.o
> >   obj-$(CONFIG_SPI_OC_TINY)		+= spi-oc-tiny.o
> >   spi-octeon-objs				:= spi-cavium.o spi-cavium-
> octeon.o
> >   obj-$(CONFIG_SPI_OCTEON)		+= spi-octeon.o
> > diff --git a/drivers/spi/spi-nxp-fspi.c b/drivers/spi/spi-nxp-fspi.c
> > new file mode 100644 index 0000000..a35013b
> > --- /dev/null
> > +++ b/drivers/spi/spi-nxp-fspi.c
> > @@ -0,0 +1,1145 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +
> > +/*
> > + * NXP FlexSPI(FSPI) controller driver.
> > + *
> > + * Copyright 2018 NXP.
> > + *
> > + * FlexSPI is a flexsible SPI host controller which supports two SPI
> > + * channels and up to 4 external devices. Each channel supports
> > + * Single/Dual/Quad/Octal mode data transfer (1/2/4/8 bidirectional
> > + * data lines).
> > + *
> > + * FlexSPI controller is driven by the LUT(Look-up Table) registers
> > + * LUT registers are a look-up-table for sequences of instructions.
> > + * A valid sequence consists of four LUT registers.
> > + * Maximum 32 LUT sequences can be programmed simultaneously.
> > + *
> > + * LUTs are being created at run-time based on the commands passed
> > + * from the spi-mem framework, thus using single LUT index.
> > + *
> > + * Software triggered Flash read/write access by IP Bus.
> > + *
> > + * Memory mapped read access by AHB Bus.
> > + *
> > + * Based on SPI MEM interface and spi-fsl-qspi.c driver.
> > + *
> > + * Author:
> > + *     Yogesh Gaur <yogeshnarayan.gaur@nxp.com>
> > + *     Boris Brezillion <boris.brezillon@bootlin.com>
> > + *     Frieder Schrempf <frieder.schrempf@kontron.de>
> > + */
> > +
> > +#include <linux/bitops.h>
> > +#include <linux/clk.h>
> > +#include <linux/completion.h>
> > +#include <linux/delay.h>
> > +#include <linux/err.h>
> > +#include <linux/errno.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/iopoll.h>
> > +#include <linux/jiffies.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/pm_qos.h>
> > +#include <linux/sizes.h>
> > +
> > +#include <linux/spi/spi.h>
> > +#include <linux/spi/spi-mem.h>
> > +
> > +/*
> > + * The driver only uses one single LUT entry, that is updated on
> > + * each call of exec_op(). Index 0 is preset at boot with a basic
> > + * read operation, so let's use the last entry (31).
> > + */
> > +#define	SEQID_LUT			31
> > +
> > +/* Registers used by the driver */
> > +#define FSPI_MCR0			0x00
> > +#define FSPI_MCR0_AHB_TIMEOUT(x)	((x) << 24)
> > +#define FSPI_MCR0_IP_TIMEOUT(x)		((x) << 16)
> > +#define FSPI_MCR0_LEARN_EN		BIT(15)
> > +#define FSPI_MCR0_SCRFRUN_EN		BIT(14)
> > +#define FSPI_MCR0_OCTCOMB_EN		BIT(13)
> > +#define FSPI_MCR0_DOZE_EN		BIT(12)
> > +#define FSPI_MCR0_HSEN			BIT(11)
> > +#define FSPI_MCR0_SERCLKDIV		BIT(8)
> > +#define FSPI_MCR0_ATDF_EN		BIT(7)
> > +#define FSPI_MCR0_ARDF_EN		BIT(6)
> > +#define FSPI_MCR0_RXCLKSRC(x)		((x) << 4)
> > +#define FSPI_MCR0_END_CFG(x)		((x) << 2)
> > +#define FSPI_MCR0_MDIS			BIT(1)
> > +#define FSPI_MCR0_SWRST			BIT(0)
> > +
> > +#define FSPI_MCR1			0x04
> > +#define FSPI_MCR1_SEQ_TIMEOUT(x)	((x) << 16)
> > +#define FSPI_MCR1_AHB_TIMEOUT(x)	(x)
> > +
> > +#define FSPI_MCR2			0x08
> > +#define FSPI_MCR2_IDLE_WAIT(x)		((x) << 24)
> > +#define FSPI_MCR2_SAMEDEVICEEN		BIT(15)
> > +#define FSPI_MCR2_CLRLRPHS		BIT(14)
> > +#define FSPI_MCR2_ABRDATSZ		BIT(8)
> > +#define FSPI_MCR2_ABRLEARN		BIT(7)
> > +#define FSPI_MCR2_ABR_READ		BIT(6)
> > +#define FSPI_MCR2_ABRWRITE		BIT(5)
> > +#define FSPI_MCR2_ABRDUMMY		BIT(4)
> > +#define FSPI_MCR2_ABR_MODE		BIT(3)
> > +#define FSPI_MCR2_ABRCADDR		BIT(2)
> > +#define FSPI_MCR2_ABRRADDR		BIT(1)
> > +#define FSPI_MCR2_ABR_CMD		BIT(0)
> > +
> > +#define FSPI_AHBCR			0x0c
> > +#define FSPI_AHBCR_RDADDROPT		BIT(6)
> > +#define FSPI_AHBCR_PREF_EN		BIT(5)
> > +#define FSPI_AHBCR_BUFF_EN		BIT(4)
> > +#define FSPI_AHBCR_CACH_EN		BIT(3)
> > +#define FSPI_AHBCR_CLRTXBUF		BIT(2)
> > +#define FSPI_AHBCR_CLRRXBUF		BIT(1)
> > +#define FSPI_AHBCR_PAR_EN		BIT(0)
> > +
> > +#define FSPI_INTEN			0x10
> > +#define FSPI_INTEN_SCLKSBWR		BIT(9)
> > +#define FSPI_INTEN_SCLKSBRD		BIT(8)
> > +#define FSPI_INTEN_DATALRNFL		BIT(7)
> > +#define FSPI_INTEN_IPTXWE		BIT(6)
> > +#define FSPI_INTEN_IPRXWA		BIT(5)
> > +#define FSPI_INTEN_AHBCMDERR		BIT(4)
> > +#define FSPI_INTEN_IPCMDERR		BIT(3)
> > +#define FSPI_INTEN_AHBCMDGE		BIT(2)
> > +#define FSPI_INTEN_IPCMDGE		BIT(1)
> > +#define FSPI_INTEN_IPCMDDONE		BIT(0)
> > +
> > +#define FSPI_INTR			0x14
> > +#define FSPI_INTR_SCLKSBWR		BIT(9)
> > +#define FSPI_INTR_SCLKSBRD		BIT(8)
> > +#define FSPI_INTR_DATALRNFL		BIT(7)
> > +#define FSPI_INTR_IPTXWE		BIT(6)
> > +#define FSPI_INTR_IPRXWA		BIT(5)
> > +#define FSPI_INTR_AHBCMDERR		BIT(4)
> > +#define FSPI_INTR_IPCMDERR		BIT(3)
> > +#define FSPI_INTR_AHBCMDGE		BIT(2)
> > +#define FSPI_INTR_IPCMDGE		BIT(1)
> > +#define FSPI_INTR_IPCMDDONE		BIT(0)
> > +
> > +#define FSPI_LUTKEY			0x18
> > +#define FSPI_LUTKEY_VALUE		0x5AF05AF0
> > +
> > +#define FSPI_LCKCR			0x1C
> > +
> > +#define FSPI_LCKER_LOCK			0x1
> > +#define FSPI_LCKER_UNLOCK		0x2
> > +
> > +#define FSPI_BUFXCR_INVALID_MSTRID	0xE
> > +#define FSPI_AHBRX_BUF0CR0		0x20
> > +#define FSPI_AHBRX_BUF1CR0		0x24
> > +#define FSPI_AHBRX_BUF2CR0		0x28
> > +#define FSPI_AHBRX_BUF3CR0		0x2C
> > +#define FSPI_AHBRX_BUF4CR0		0x30
> > +#define FSPI_AHBRX_BUF5CR0		0x34
> > +#define FSPI_AHBRX_BUF6CR0		0x38
> > +#define FSPI_AHBRX_BUF7CR0		0x3C
> > +#define FSPI_AHBRXBUF0CR7_PREF		BIT(31)
> > +
> > +#define FSPI_AHBRX_BUF0CR1		0x40
> > +#define FSPI_AHBRX_BUF1CR1		0x44
> > +#define FSPI_AHBRX_BUF2CR1		0x48
> > +#define FSPI_AHBRX_BUF3CR1		0x4C
> > +#define FSPI_AHBRX_BUF4CR1		0x50
> > +#define FSPI_AHBRX_BUF5CR1		0x54
> > +#define FSPI_AHBRX_BUF6CR1		0x58
> > +#define FSPI_AHBRX_BUF7CR1		0x5C
> > +
> > +#define FSPI_FLSHA1CR0			0x60
> > +#define FSPI_FLSHA2CR0			0x64
> > +#define FSPI_FLSHB1CR0			0x68
> > +#define FSPI_FLSHB2CR0			0x6C
> > +#define FSPI_FLSHXCR0_SZ_KB		10
> > +#define FSPI_FLSHXCR0_SZ(x)		((x) >> FSPI_FLSHXCR0_SZ_KB)
> > +
> > +#define FSPI_FLSHA1CR1			0x70
> > +#define FSPI_FLSHA2CR1			0x74
> > +#define FSPI_FLSHB1CR1			0x78
> > +#define FSPI_FLSHB2CR1			0x7C
> > +#define FSPI_FLSHXCR1_CSINTR(x)		((x) << 16)
> > +#define FSPI_FLSHXCR1_CAS(x)		((x) << 11)
> > +#define FSPI_FLSHXCR1_WA		BIT(10)
> > +#define FSPI_FLSHXCR1_TCSH(x)		((x) << 5)
> > +#define FSPI_FLSHXCR1_TCSS(x)		(x)
> > +
> > +#define FSPI_FLSHA1CR2			0x80
> > +#define FSPI_FLSHA2CR2			0x84
> > +#define FSPI_FLSHB1CR2			0x88
> > +#define FSPI_FLSHB2CR2			0x8C
> > +#define FSPI_FLSHXCR2_CLRINSP		BIT(24)
> > +#define FSPI_FLSHXCR2_AWRWAIT		BIT(16)
> > +#define FSPI_FLSHXCR2_AWRSEQN_SHIFT	13
> > +#define FSPI_FLSHXCR2_AWRSEQI_SHIFT	8
> > +#define FSPI_FLSHXCR2_ARDSEQN_SHIFT	5
> > +#define FSPI_FLSHXCR2_ARDSEQI_SHIFT	0
> > +
> > +#define FSPI_IPCR0			0xA0
> > +
> > +#define FSPI_IPCR1			0xA4
> > +#define FSPI_IPCR1_IPAREN		BIT(31)
> > +#define FSPI_IPCR1_SEQNUM_SHIFT		24
> > +#define FSPI_IPCR1_SEQID_SHIFT		16
> > +#define FSPI_IPCR1_IDATSZ(x)		(x)
> > +
> > +#define FSPI_IPCMD			0xB0
> > +#define FSPI_IPCMD_TRG			BIT(0)
> > +
> > +#define FSPI_DLPR			0xB4
> > +
> > +#define FSPI_IPRXFCR			0xB8
> > +#define FSPI_IPRXFCR_CLR		BIT(0)
> > +#define FSPI_IPRXFCR_DMA_EN		BIT(1)
> > +#define FSPI_IPRXFCR_WMRK(x)		((x) << 2)
> > +
> > +#define FSPI_IPTXFCR			0xBC
> > +#define FSPI_IPTXFCR_CLR		BIT(0)
> > +#define FSPI_IPTXFCR_DMA_EN		BIT(1)
> > +#define FSPI_IPTXFCR_WMRK(x)		((x) << 2)
> > +
> > +#define FSPI_DLLACR			0xC0
> > +#define FSPI_DLLACR_OVRDEN		BIT(8)
> > +
> > +#define FSPI_DLLBCR			0xC4
> > +#define FSPI_DLLBCR_OVRDEN		BIT(8)
> > +
> > +#define FSPI_STS0			0xE0
> > +#define FSPI_STS0_DLPHB(x)		((x) << 8)
> > +#define FSPI_STS0_DLPHA(x)		((x) << 4)
> > +#define FSPI_STS0_CMD_SRC(x)		((x) << 2)
> > +#define FSPI_STS0_ARB_IDLE		BIT(1)
> > +#define FSPI_STS0_SEQ_IDLE		BIT(0)
> > +
> > +#define FSPI_STS1			0xE4
> > +#define FSPI_STS1_IP_ERRCD(x)		((x) << 24)
> > +#define FSPI_STS1_IP_ERRID(x)		((x) << 16)
> > +#define FSPI_STS1_AHB_ERRCD(x)		((x) << 8)
> > +#define FSPI_STS1_AHB_ERRID(x)		(x)
> > +
> > +#define FSPI_AHBSPNST			0xEC
> > +#define FSPI_AHBSPNST_DATLFT(x)		((x) << 16)
> > +#define FSPI_AHBSPNST_BUFID(x)		((x) << 1)
> > +#define FSPI_AHBSPNST_ACTIVE		BIT(0)
> > +
> > +#define FSPI_IPRXFSTS			0xF0
> > +#define FSPI_IPRXFSTS_RDCNTR(x)		((x) << 16)
> > +#define FSPI_IPRXFSTS_FILL(x)		(x)
> > +
> > +#define FSPI_IPTXFSTS			0xF4
> > +#define FSPI_IPTXFSTS_WRCNTR(x)		((x) << 16)
> > +#define FSPI_IPTXFSTS_FILL(x)		(x)
> > +
> > +#define FSPI_RFDR			0x100
> > +#define FSPI_TFDR			0x180
> > +
> > +#define FSPI_LUT_BASE			0x200
> > +#define FSPI_LUT_OFFSET			(SEQID_LUT * 4 * 4)
> > +#define FSPI_LUT_REG(idx) \
> > +	(FSPI_LUT_BASE + FSPI_LUT_OFFSET + (idx) * 4)
> > +
> > +/* register map end */
> > +
> > +/* Instruction set for the LUT register. */
> > +#define LUT_STOP			0x00
> > +#define LUT_CMD				0x01
> > +#define LUT_ADDR			0x02
> > +#define LUT_CADDR_SDR			0x03
> > +#define LUT_MODE			0x04
> > +#define LUT_MODE2			0x05
> > +#define LUT_MODE4			0x06
> > +#define LUT_MODE8			0x07
> > +#define LUT_NXP_WRITE			0x08
> > +#define LUT_NXP_READ			0x09
> > +#define LUT_LEARN_SDR			0x0A
> > +#define LUT_DATSZ_SDR			0x0B
> > +#define LUT_DUMMY			0x0C
> > +#define LUT_DUMMY_RWDS_SDR		0x0D
> > +#define LUT_JMP_ON_CS			0x1F
> > +#define LUT_CMD_DDR			0x21
> > +#define LUT_ADDR_DDR			0x22
> > +#define LUT_CADDR_DDR			0x23
> > +#define LUT_MODE_DDR			0x24
> > +#define LUT_MODE2_DDR			0x25
> > +#define LUT_MODE4_DDR			0x26
> > +#define LUT_MODE8_DDR			0x27
> > +#define LUT_WRITE_DDR			0x28
> > +#define LUT_READ_DDR			0x29
> > +#define LUT_LEARN_DDR			0x2A
> > +#define LUT_DATSZ_DDR			0x2B
> > +#define LUT_DUMMY_DDR			0x2C
> > +#define LUT_DUMMY_RWDS_DDR		0x2D
> > +
> > +/*
> > + * Calculate number of required PAD bits for LUT register.
> > + *
> > + * The pad stands for the number of IO lines [0:7].
> > + * For example, the octal read needs eight IO lines,
> > + * so you should use LUT_PAD(8). This macro
> > + * returns 3 i.e. use eight (2^3) IP lines for read.
> > + */
> > +#define LUT_PAD(x) (fls(x) - 1)
> > +
> > +/*
> > + * Macro for constructing the LUT entries with the following
> > + * register layout:
> > + *
> > + *  ---------------------------------------------------
> > + *  | INSTR1 | PAD1 | OPRND1 | INSTR0 | PAD0 | OPRND0 |
> > + *  ---------------------------------------------------
> > + */
> > +#define PAD_SHIFT		8
> > +#define INSTR_SHIFT		10
> > +#define OPRND_SHIFT		16
> > +
> > +/* Macros for constructing the LUT register. */
> > +#define LUT_DEF(idx, ins, pad, opr)			  \
> > +	((((ins) << INSTR_SHIFT) | ((pad) << PAD_SHIFT) | \
> > +	(opr)) << (((idx) % 2) * OPRND_SHIFT))
> > +
> > +/* Operands for the LUT register. */
> > +#define ADDR8BIT		0x08
> > +#define ADDR16BIT		0x10
> > +#define ADDR24BIT		0x18
> > +#define ADDR32BIT		0x20
> 
> You can drop these ADDRXBIT definitions, see below...
> 
Ok, would drop in next version.

> > +
> > +#define POLL_TOUT		5000
> > +#define NXP_FSPI_MAX_CHIPSELECT		4
> > +
> > +struct nxp_fspi_devtype_data {
> > +	unsigned int rxfifo;
> > +	unsigned int txfifo;
> > +	unsigned int ahb_buf_size;
> > +	unsigned int quirks;
> > +	bool little_endian;
> > +};
> > +
> > +static const struct nxp_fspi_devtype_data lx2160a_data = {
> > +	.rxfifo = SZ_512,       /* (64  * 64 bits)  */
> > +	.txfifo = SZ_1K,        /* (128 * 64 bits)  */
> > +	.ahb_buf_size = SZ_2K,  /* (256 * 64 bits)  */
> > +	.quirks = 0,
> > +	.little_endian = true,  /* little-endian    */
> > +};
> > +
> > +struct nxp_fspi {
> > +	void __iomem *iobase;
> > +	void __iomem *ahb_addr;
> > +	u32 memmap_phy;
> > +	u32 memmap_phy_size;
> > +	struct clk *clk, *clk_en;
> > +	struct device *dev;
> > +	struct completion c;
> > +	const struct nxp_fspi_devtype_data *devtype_data;
> > +	struct mutex lock;
> > +	struct pm_qos_request pm_qos_req;
> > +	int selected;
> > +};
> > +
> > +/*
> > + * R/W functions for big- or little-endian registers:
> > + * The FSPI controller's endianness is independent of
> > + * the CPU core's endianness. So far, although the CPU
> > + * core is little-endian the FSPI controller can use
> > + * big-endian or little-endian.
> > + */
> > +static void fspi_writel(struct nxp_fspi *f, u32 val, void __iomem
> > +*addr) {
> > +	if (f->devtype_data->little_endian)
> > +		iowrite32(val, addr);
> > +	else
> > +		iowrite32be(val, addr);
> > +}
> > +
> > +static u32 fspi_readl(struct nxp_fspi *f, void __iomem *addr) {
> > +	if (f->devtype_data->little_endian)
> > +		return ioread32(addr);
> > +	else
> > +		return ioread32be(addr);
> > +}
> > +
> > +static irqreturn_t nxp_fspi_irq_handler(int irq, void *dev_id) {
> > +	struct nxp_fspi *f = dev_id;
> > +	u32 reg;
> > +
> > +	/* clear interrupt */
> > +	reg = fspi_readl(f, f->iobase + FSPI_INTR);
> > +	fspi_writel(f, FSPI_INTR_IPCMDDONE, f->iobase + FSPI_INTR);
> > +
> > +	if (reg & FSPI_INTR_IPCMDDONE)
> > +		complete(&f->c);
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static int nxp_fspi_check_buswidth(struct nxp_fspi *f, u8 width) {
> > +	switch (width) {
> > +	case 1:
> > +	case 2:
> > +	case 4:
> > +	case 8:
> > +		return 0;
> > +	}
> > +
> > +	return -ENOTSUPP;
> > +}
> > +
> > +static bool nxp_fspi_supports_op(struct spi_mem *mem,
> > +				 const struct spi_mem_op *op)
> > +{
> > +	struct nxp_fspi *f = spi_controller_get_devdata(mem->spi->master);
> > +	int ret;
> > +
> > +	ret = nxp_fspi_check_buswidth(f, op->cmd.buswidth);
> > +
> > +	if (op->addr.nbytes)
> > +		ret |= nxp_fspi_check_buswidth(f, op->addr.buswidth);
> > +
> > +	if (op->dummy.nbytes)
> > +		ret |= nxp_fspi_check_buswidth(f, op->dummy.buswidth);
> > +
> > +	if (op->data.nbytes)
> > +		ret |= nxp_fspi_check_buswidth(f, op->data.buswidth);
> > +
> > +	if (ret)
> > +		return false;
> > +
> > +	/*
> > +	 * The number of instructions needed for the op, needs
> > +	 * to fit into a single LUT entry.
> > +	 */
> > +	if (op->addr.nbytes +
> > +	   (op->dummy.nbytes ? 1:0) +
> > +	   (op->data.nbytes ? 1:0) > 6)
> > +		return false;
> > +
> > +	/* Max 64 dummy clock cycles supported */
> > +	if (op->dummy.buswidth &&
> > +	    (op->dummy.nbytes * 8 / op->dummy.buswidth > 64))
> > +		return false;
> > +
> > +	/* Max data length, check controller limits and alignment */
> > +	if (op->data.dir == SPI_MEM_DATA_IN &&
> > +	    (op->data.nbytes > f->devtype_data->ahb_buf_size ||
> > +	     (op->data.nbytes > f->devtype_data->rxfifo - 4 &&
> > +	      !IS_ALIGNED(op->data.nbytes, 8))))
> > +		return false;
> > +
> > +	if (op->data.dir == SPI_MEM_DATA_OUT &&
> > +	    op->data.nbytes > f->devtype_data->txfifo)
> > +		return false;
> > +
> > +	return true;
> > +}
> > +
> > +/* Instead of busy looping invoke readl_poll_timeout functionality.
> > +*/ static int fspi_readl_poll_tout(struct nxp_fspi *f, void __iomem *base,
> > +				u32 mask, u32 delay_us,
> > +				u32 timeout_us, bool condition)
> > +{
> > +	u32 reg;
> > +
> > +	if (!f->devtype_data->little_endian)
> > +		mask = (u32)cpu_to_be32(mask);
> > +
> > +	if (condition)
> > +		return readl_poll_timeout(base, reg, (reg & mask),
> > +					  delay_us, timeout_us);
> > +	else
> > +		return readl_poll_timeout(base, reg, !(reg & mask),
> > +					  delay_us, timeout_us);
> 
> I would rather use a local variable to store the condition:
> 
> bool c = condition ? (reg & mask):!(reg & mask);
> 
With these type of usage getting below warning messages.
 
drivers/spi/spi-nxp-fspi.c: In function ‘fspi_readl_poll_tout.isra.10.constprop’:
drivers/spi/spi-nxp-fspi.c:446:21: warning: ‘reg’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  bool cn = c ? (reg & mask) : !(reg & mask);

If assign value to reg = 0xffffffff then timeout is start getting hit for False case and if assign value 0 then start getting timeout hit for true case.

I would rather not try to modify this function.

> return readl_poll_timeout(base, reg, c, delay_us, timeout_us);
> 
> > +}
> > +
> > +/*
> > + * If the slave device content being changed by Write/Erase, need to
> > + * invalidate the AHB buffer. This can be achieved by doing the reset
> > + * of controller after setting MCR0[SWRESET] bit.
> > + */
> > +static inline void nxp_fspi_invalid(struct nxp_fspi *f) {
> > +	u32 reg;
> > +	int ret;
> > +
> > +	reg = fspi_readl(f, f->iobase + FSPI_MCR0);
> > +	fspi_writel(f, reg | FSPI_MCR0_SWRST, f->iobase + FSPI_MCR0);
> > +
> > +	/* w1c register, wait unit clear */
> > +	ret = fspi_readl_poll_tout(f, f->iobase + FSPI_MCR0,
> > +				   FSPI_MCR0_SWRST, 0, POLL_TOUT, false);
> > +	WARN_ON(ret);
> > +}
> > +
> > +static void nxp_fspi_prepare_lut(struct nxp_fspi *f,
> > +				 const struct spi_mem_op *op)
> > +{
> > +	void __iomem *base = f->iobase;
> > +	u32 lutval[4] = {};
> > +	int lutidx = 1, i;
> > +
> > +	/* cmd */
> > +	lutval[0] |= LUT_DEF(0, LUT_CMD, LUT_PAD(op->cmd.buswidth),
> > +			     op->cmd.opcode);
> > +
> > +	/* addr bus width */
> > +	if (op->addr.nbytes) {
> > +		u32 addrlen = 0;
> > +
> > +		switch (op->addr.nbytes) {
> > +		case 1:
> > +			addrlen = ADDR8BIT;
> > +			break;
> > +		case 2:
> > +			addrlen = ADDR16BIT;
> > +			break;
> > +		case 3:
> > +			addrlen = ADDR24BIT;
> > +			break;
> > +		case 4:
> > +			addrlen = ADDR32BIT;
> > +			break;
> > +		default:
> > +			dev_err(f->dev, "In-correct address length\n");
> > +			return;
> > +		}
> 
> You don't need to validate op->addr.nbytes here, this is already done in
> nxp_fspi_supports_op().

Yes, I need to validate op->addr.nbytes else LUT would going to be programmed for 0 addrlen.
I have checked this on the target.

> 
> > +
> > +		lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_ADDR,
> > +					      LUT_PAD(op->addr.buswidth),
> > +					      addrlen);
> 
> You can also just remove the whole switch statement above and use this:
> 
> lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_ADDR,
> 			      LUT_PAD(op->addr.buswidth),
> 			      op->addr.nbytes * 8);
> 
Ok, would include in next version.

> > +		lutidx++;
> > +	}
> > +
> > +	/* dummy bytes, if needed */
> > +	if (op->dummy.nbytes) {
> > +		lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_DUMMY,
> > +		/*
> > +		 * Due to FlexSPI controller limitation number of PAD for
> dummy
> > +		 * buswidth needs to be programmed as equal to data buswidth.
> > +		 */
> > +					      LUT_PAD(op->data.buswidth),
> > +					      op->dummy.nbytes * 8 /
> > +					      op->dummy.buswidth);
> > +		lutidx++;
> > +	}
> > +
> > +	/* read/write data bytes */
> > +	if (op->data.nbytes) {
> > +		lutval[lutidx / 2] |= LUT_DEF(lutidx,
> > +					      op->data.dir ==
> SPI_MEM_DATA_IN ?
> > +					      LUT_NXP_READ : LUT_NXP_WRITE,
> > +					      LUT_PAD(op->data.buswidth),
> > +					      0);
> > +		lutidx++;
> > +	}
> > +
> > +	/* stop condition. */
> > +	lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_STOP, 0, 0);
> > +
> > +	/* unlock LUT */
> > +	fspi_writel(f, FSPI_LUTKEY_VALUE, f->iobase + FSPI_LUTKEY);
> > +	fspi_writel(f, FSPI_LCKER_UNLOCK, f->iobase + FSPI_LCKCR);
> > +
> > +	/* fill LUT */
> > +	for (i = 0; i < ARRAY_SIZE(lutval); i++)
> > +		fspi_writel(f, lutval[i], base + FSPI_LUT_REG(i));
> > +
> > +	dev_dbg(f->dev, "CMD[%x] lutval[0:%x \t 1:%x \t 2:%x \t 3:%x]\n",
> > +		op->cmd.opcode, lutval[0], lutval[1], lutval[2], lutval[3]);
> > +
> > +	/* lock LUT */
> > +	fspi_writel(f, FSPI_LUTKEY_VALUE, f->iobase + FSPI_LUTKEY);
> > +	fspi_writel(f, FSPI_LCKER_LOCK, f->iobase + FSPI_LCKCR); }
> > +
> > +static int nxp_fspi_clk_prep_enable(struct nxp_fspi *f) {
> > +	int ret;
> > +
> > +	ret = clk_prepare_enable(f->clk_en);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = clk_prepare_enable(f->clk);
> > +	if (ret) {
> > +		clk_disable_unprepare(f->clk_en);
> > +		return ret;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static void nxp_fspi_clk_disable_unprep(struct nxp_fspi *f) {
> > +	clk_disable_unprepare(f->clk);
> > +	clk_disable_unprepare(f->clk_en);
> > +}
> > +
> > +/*
> > + * In FlexSPI controller, flash access is based on value of
> > +FSPI_FLSHXXCR0
> > + * register and start base address of the slave device.
> > + *
> > + *							    (Higher address)
> > + *				--------    <-- FLSHB2CR0
> > + *				|  B2  |
> > + *				|      |
> > + *	B2 start address -->	--------    <-- FLSHB1CR0
> > + *				|  B1  |
> > + *				|      |
> > + *	B1 start address -->	--------    <-- FLSHA2CR0
> > + *				|  A2  |
> > + *				|      |
> > + *	A2 start address -->	--------    <-- FLSHA1CR0
> > + *				|  A1  |
> > + *				|      |
> > + *	A1 start address -->	--------		    (Lower address)
> > + *
> > + *
> > + * Start base address defines the starting address range for given CS
> > +and
> > + * FSPI_FLSHXXCR0 defines the size of the slave device connected at given CS.
> > + *
> > + * But, different targets are having different combinations of number
> > +of CS,
> > + * some targets only have single CS or two CS covering controller's
> > +full
> > + * memory mapped space area.
> > + * Thus, implementation is being done as independent of the size and
> > +number
> > + * of the connected slave device.
> > + * Assign controller memory mapped space size as the size to the
> > +connected
> > + * slave device.
> > + * Mark FLSHxxCR0 as zero initially and then assign value only to the
> > +selected
> > + * chip-select Flash configuration register.
> > + *
> > + * For e.g. to access CS2 (B1), FLSHB1CR0 register would be equal to
> > +the
> > + * memory mapped size of the controller.
> > + * Value for rest of the CS FLSHxxCR0 register would be zero.
> > + *
> > + */
> > +static void nxp_fspi_select_mem(struct nxp_fspi *f, struct spi_device
> > +*spi) {
> > +	unsigned long rate = spi->max_speed_hz;
> > +	int ret;
> > +	uint64_t size_kb;
> > +
> > +	/*
> > +	 * Return, if previously selected slave device is same as current
> > +	 * requested slave device.
> > +	 */
> > +	if (f->selected == spi->chip_select)
> > +		return;
> > +
> > +	/* Reset FLSHxxCR0 registers */
> > +	fspi_writel(f, 0, f->iobase + FSPI_FLSHA1CR0);
> > +	fspi_writel(f, 0, f->iobase + FSPI_FLSHA2CR0);
> > +	fspi_writel(f, 0, f->iobase + FSPI_FLSHB1CR0);
> > +	fspi_writel(f, 0, f->iobase + FSPI_FLSHB2CR0);
> > +
> > +	/* Assign controller memory mapped space as size, KBytes, of flash. */
> > +	size_kb = FSPI_FLSHXCR0_SZ(f->memmap_phy_size);
> 
Above description of this function, explains the reason for using memmap_phy_size.
This is not the arbitrary size, but the memory mapped size being assigned to the controller.

> You are still using memory of arbitrary size (memmap_phy_size) for mapping the
> flash. Why not use the same approach as in the QSPI driver and just map
> ahb_buf_size until we implement the dirmap API?
The approach which being used in QSPI driver didn't work here, I have tried with that.
In QSPI driver, while preparing LUT we are assigning read/write address in the LUT preparation and have to for some unknown hack have to provide macro for LUT_MODE instead of LUT_ADDR.
But this thing didn't work for FlexSPI.
I discussed with HW IP owner and they suggested only to use LUT_ADDR for specifying the address length of the command i.e. 3-byte or 4-byte address command (NOR) or 1-2 byte address command for NAND.

Thus, in LUT preparation we have assigned only the base address.
Now if I have assigned ahb_buf_size to FSPI_FLSHXXCR0 register then for read/write data beyond limit of ahb_buf_size offset I get data corruption.

Thus, for generic approach have assigned FSPI_FLSHXXCR0 equal to the memory mapped size to the controller. This would also not going to depend on the number of CS present on the target.

> You are already aligning the AHB reads for this in nxp_fspi_adjust_op_size().
> 
Yes, max read data size can be ahb_buf_size. Thus we need to check max read size with ahb_buf_size.

> > +
> > +	switch (spi->chip_select) {
> > +	case 0:
> > +		fspi_writel(f, size_kb, f->iobase + FSPI_FLSHA1CR0);
> > +		break;
> > +	case 1:
> > +		fspi_writel(f, size_kb, f->iobase + FSPI_FLSHA2CR0);
> > +		break;
> > +	case 2:
> > +		fspi_writel(f, size_kb, f->iobase + FSPI_FLSHB1CR0);
> > +		break;
> > +	case 3:
> > +		fspi_writel(f, size_kb, f->iobase + FSPI_FLSHB2CR0);
> > +		break;
> > +	default:
> > +		dev_err(f->dev, "In-correct CS provided\n");
> > +		return;
> 
> You don't need to validate spi->chip_select here. This should never be invalid
> and if it is, something is really wrong and your check won't help.
Ok, would remove in next version.

> 
> > +	}
> > +
> > +	dev_dbg(f->dev, "Slave device [CS:%x] selected\n",
> > +spi->chip_select);
> > +
> > +	nxp_fspi_clk_disable_unprep(f);
> > +
> > +	ret = clk_set_rate(f->clk, rate);
> > +	if (ret)
> > +		return;
> > +
> > +	ret = nxp_fspi_clk_prep_enable(f);
> > +	if (ret)
> > +		return;
> 
> Missing newline line here.
Ok

> 
> > +	f->selected = spi->chip_select;
> > +}
> > +
> > +static void nxp_fspi_read_ahb(struct nxp_fspi *f, const struct
> > +spi_mem_op *op) {
> > +	u32 len = op->data.nbytes;
> > +
> > +	/* Read out the data directly from the AHB buffer. */
> > +	memcpy_fromio(op->data.buf.in, (f->ahb_addr + op->addr.val), len); }
> > +
> > +static void nxp_fspi_fill_txfifo(struct nxp_fspi *f,
> > +				 const struct spi_mem_op *op)
> > +{
> > +	void __iomem *base = f->iobase;
> > +	int i, j, ret;
> > +	int size, tmp_size, wm_size;
> > +	u32 data = 0;
> > +	u32 *txbuf = (u32 *) op->data.buf.out;
> > +
> > +	/* clear the TX FIFO. */
> > +	fspi_writel(f, FSPI_IPTXFCR_CLR, base + FSPI_IPTXFCR);
> > +
> > +	/* Default value of water mark level is 8 bytes. */
> > +	wm_size = 8;
> > +	size = op->data.nbytes / wm_size;
> > +	for (i = 0; i < size; i++) {
> > +		/* Wait for TXFIFO empty */
> > +		ret = fspi_readl_poll_tout(f, f->iobase + FSPI_INTR,
> > +					   FSPI_INTR_IPTXWE, 0,
> > +					   POLL_TOUT, true);
> > +		WARN_ON(ret);
> > +
> > +		j = 0;
> > +		tmp_size = wm_size;
> > +		while (tmp_size > 0) {
> > +			data = 0;
> > +			memcpy(&data, txbuf, 4);
> > +			fspi_writel(f, data, base + FSPI_TFDR + j * 4);
> > +			tmp_size -= 4;
> > +			j++;
> > +			txbuf += 1;
> > +		}
> > +		fspi_writel(f, FSPI_INTR_IPTXWE, base + FSPI_INTR);
> > +	}
> > +
> > +	size = op->data.nbytes % wm_size;
> > +	if (size) {
> > +		/* Wait for TXFIFO empty */
> > +		ret = fspi_readl_poll_tout(f, f->iobase + FSPI_INTR,
> > +					   FSPI_INTR_IPTXWE, 0,
> > +					   POLL_TOUT, true);
> > +		WARN_ON(ret);
> > +
> > +		j = 0;
> > +		tmp_size = 0;
> > +		while (size > 0) {
> > +			data = 0;
> > +			tmp_size = (size < 4) ? size : 4;
> > +			memcpy(&data, txbuf, tmp_size);
> > +			fspi_writel(f, data, base + FSPI_TFDR + j * 4);
> > +			size -= tmp_size;
> > +			j++;
> > +			txbuf += 1;
> > +		}
> > +		fspi_writel(f, FSPI_INTR_IPTXWE, base + FSPI_INTR);
> > +	}
> 
> All these nested loops to fill the TX buffer and also the ones below to read the
> RX buffer look much more complicated than they should really be. Can you try to
> make this more readable?
Yes
> 
> Maybe something like this would work:
> 
> for (i = 0; i < ALIGN_DOWN(op->data.nbytes, 8); i += 8) {
> 	/* Wait for TXFIFO empty */
> 	ret = fspi_readl_poll_tout(f, f->iobase + FSPI_INTR,
> 				   FSPI_INTR_IPTXWE, 0,
> 				   POLL_TOUT, true);
> 
> 	fspi_writel(f, op->data.buf.out + i, base + FSPI_TFDR);
> 	fspi_writel(f, op->data.buf.out + i + 4, base + FSPI_TFDR + 4);
> 	fspi_writel(f, FSPI_INTR_IPTXWE, base + FSPI_INTR); }
With this above 2 lines we are hardcoding it for read/write with watermark size as 8 bytes.
Watermark size can be variable and depends on the value of IPRXFCR/IPTXFCR register with default value as 8 bytes
Thus, I would still prefer to use the internal for loop instead of 2 fspi_writel(...) for FSPI_TFDR and FSPI_TFDR + 4 register write commands.

> 
> if (i < op->data.nbytes) {
> 	u32 data = 0;
> 	int j;
> 	/* Wait for TXFIFO empty */
> 	ret = fspi_readl_poll_tout(f, f->iobase + FSPI_INTR,
> 				   FSPI_INTR_IPTXWE, 0,
> 				   POLL_TOUT, true);
> 
> 	for (j = 0; j < ALIGN(op->data.nbytes - i, 4); j += 4) {
> 		memcpy(&data, op->data.buf.out + i + j, 4);
> 		fspi_writel(f, data, base + FSPI_TFDR + j);
> 	}
> 
> 	fspi_writel(f, FSPI_INTR_IPTXWE, base + FSPI_INTR); }
> 
> > +}
> > +
> > +static void nxp_fspi_read_rxfifo(struct nxp_fspi *f,
> > +			  const struct spi_mem_op *op)
> > +{
> > +	void __iomem *base = f->iobase;
> > +	int i, j;
> > +	int size, tmp_size, wm_size, ret;
> > +	u32 tmp = 0;
> > +	u8 *buf = op->data.buf.in;
> > +	u32 len = op->data.nbytes;
> > +
> > +	/* Default value of water mark level is 8 bytes. */
> > +	wm_size = 8;
> > +
> > +	while (len > 0) {
> > +		size = len / wm_size;
> > +
> > +		for (i = 0; i < size; i++) {
> > +			/* Wait for RXFIFO available */
> > +			ret = fspi_readl_poll_tout(f, f->iobase + FSPI_INTR,
> > +						   FSPI_INTR_IPRXWA, 0,
> > +						   POLL_TOUT, true);
> > +			WARN_ON(ret);
> > +
> > +			j = 0;
> > +			tmp_size = wm_size;
> > +			while (tmp_size > 0) {
> > +				tmp = 0;
> > +				tmp = fspi_readl(f, base + FSPI_RFDR + j * 4);
> > +				memcpy(buf, &tmp, 4);
> > +				tmp_size -= 4;
> > +				j++;
> > +				buf += 4;
> > +			}
> > +			/* move the FIFO pointer */
> > +			fspi_writel(f, FSPI_INTR_IPRXWA, base + FSPI_INTR);
> > +			len -= wm_size;
> > +		}
> > +
> > +		size = len % wm_size;
> > +
> > +		j = 0;
> > +		if (size) {
> > +			/* Wait for RXFIFO available */
> > +			ret = fspi_readl_poll_tout(f, f->iobase + FSPI_INTR,
> > +						   FSPI_INTR_IPRXWA, 0,
> > +						   POLL_TOUT, true);
> > +			WARN_ON(ret);
> > +
> > +			while (len > 0) {
> > +				tmp = 0;
> > +				size = (len < 4) ? len : 4;
> > +				tmp = fspi_readl(f, base + FSPI_RFDR + j * 4);
> > +				memcpy(buf, &tmp, size);
> > +				len -= size;
> > +				j++;
> > +				buf += size;
> > +			}
> > +		}
> > +
> > +		/* invalid the RXFIFO */
> > +		fspi_writel(f, FSPI_IPRXFCR_CLR, base + FSPI_IPRXFCR);
> > +		/* move the FIFO pointer */
> > +		fspi_writel(f, FSPI_INTR_IPRXWA, base + FSPI_INTR);
> > +	}
> 
> Same here. I think this is overly complicated.
> 
Yes, would do in next version.

> > +}
> > +
> > +static int nxp_fspi_do_op(struct nxp_fspi *f, const struct spi_mem_op
> > +*op) {
> > +	void __iomem *base = f->iobase;
> > +	int seqnum = 0;
> > +	int err = 0;
> > +	u32 reg;
> > +
> > +	reg = fspi_readl(f, base + FSPI_IPRXFCR);
> > +	/* invalid RXFIFO first */
> > +	reg &= ~FSPI_IPRXFCR_DMA_EN;
> > +	reg = reg | FSPI_IPRXFCR_CLR;
> > +	fspi_writel(f, reg, base + FSPI_IPRXFCR);
> > +
> > +	init_completion(&f->c);
> > +
> > +	fspi_writel(f, op->addr.val, base + FSPI_IPCR0);
> > +	/*
> > +	 * Always start the sequence at the same index since we update
> > +	 * the LUT at each exec_op() call. And also specify the DATA
> > +	 * length, since it's has not been specified in the LUT.
> > +	 */
> > +	fspi_writel(f, op->data.nbytes |
> > +		 (SEQID_LUT << FSPI_IPCR1_SEQID_SHIFT) |
> > +		 (seqnum << FSPI_IPCR1_SEQNUM_SHIFT),
> > +		 base + FSPI_IPCR1);
> > +
> > +	/* Trigger the LUT now. */
> > +	fspi_writel(f, FSPI_IPCMD_TRG, base + FSPI_IPCMD);
> > +
> > +	/* Wait for the interrupt. */
> > +	if (!wait_for_completion_timeout(&f->c, msecs_to_jiffies(1000)))
> > +		err = -ETIMEDOUT;
> > +
> > +	/* Invoke IP data read, if request is of data read. */
> > +	if (!err && op->data.nbytes && op->data.dir == SPI_MEM_DATA_IN)
> > +		nxp_fspi_read_rxfifo(f, op);
> > +
> > +	return err;
> > +}
> > +
> > +static int nxp_fspi_exec_op(struct spi_mem *mem, const struct
> > +spi_mem_op *op) {
> > +	struct nxp_fspi *f = spi_controller_get_devdata(mem->spi->master);
> > +	int err = 0;
> > +
> > +	mutex_lock(&f->lock);
> > +
> > +	/* Wait for controller being ready. */
> > +	err = fspi_readl_poll_tout(f, f->iobase + FSPI_STS0,
> > +				   FSPI_STS0_ARB_IDLE, 1, POLL_TOUT, true);
> > +	WARN_ON(err);
> > +
> > +	nxp_fspi_select_mem(f, mem->spi);
> > +
> > +	nxp_fspi_prepare_lut(f, op);
> > +	/*
> > +	 * If we have large chunks of data, we read them through the AHB bus
> > +	 * by accessing the mapped memory. In all other cases we use
> > +	 * IP commands to access the flash.
> > +	 */
> > +	if (op->data.nbytes > (f->devtype_data->rxfifo - 4) &&
> > +	    op->data.dir == SPI_MEM_DATA_IN) {
> > +		nxp_fspi_read_ahb(f, op);
> > +	} else {
> > +		if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_OUT)
> > +			nxp_fspi_fill_txfifo(f, op);
> > +
> > +		err = nxp_fspi_do_op(f, op);
> > +
> > +		/* Invalidate the data in the AHB buffer. */
> > +		if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_OUT)
> > +			nxp_fspi_invalid(f);
> 
> E.g. in case of an erase operation or a NAND load page operation, the
> invalidation is not triggered, but flash/buffer contents have changed.
> So I'm not sure if this is enough...
Ok, would change this and have invalidate for all operations.

> 
> > +	}
> > +
> > +	mutex_unlock(&f->lock);
> > +
> > +	return err;
> > +}
> > +
> > +static int nxp_fspi_adjust_op_size(struct spi_mem *mem, struct
> > +spi_mem_op *op) {
> > +	struct nxp_fspi *f = spi_controller_get_devdata(mem->spi->master);
> > +
> > +	if (op->data.dir == SPI_MEM_DATA_OUT) {
> > +		if (op->data.nbytes > f->devtype_data->txfifo)
> > +			op->data.nbytes = f->devtype_data->txfifo;
> > +	} else {
> > +		if (op->data.nbytes > f->devtype_data->ahb_buf_size)
> > +			op->data.nbytes = f->devtype_data->ahb_buf_size;
> > +		else if (op->data.nbytes > (f->devtype_data->rxfifo - 4))
> > +			op->data.nbytes = ALIGN_DOWN(op->data.nbytes, 8);
> 
> You are using the same alignments as in the QSPI driver. So AHB reads will
> happen in portions of ahb_buf_size, but you dont' stick to this when you map the
> memory. See above.

Reason mentioned above.

--
Regards
Yogesh Gaur

> 
> Regards,
> Frieder
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