Message-ID: <MWHPR02MB2623C67196CAFD239736B6A1AF700@MWHPR02MB2623.namprd02.prod.outlook.com>
Date:   Tue, 19 Jun 2018 10:54:00 +0000
From:   Naga Sureshkumar Relli <nagasure@...inx.com>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
CC:     "boris.brezillon@...tlin.com" <boris.brezillon@...tlin.com>,
        "richard@....at" <richard@....at>,
        "wmw2@...radead.org" <wmw2@...radead.org>,
        "computersforpeace@...il.com" <computersforpeace@...il.com>,
        "marek.vasut@...il.com" <marek.vasut@...il.com>,
        "f.fainelli@...il.com" <f.fainelli@...il.com>,
        "mmayer@...adcom.com" <mmayer@...adcom.com>,
        "rogerq@...com" <rogerq@...com>,
        "ladis@...ux-mips.org" <ladis@...ux-mips.org>,
        "ada@...rsis.com" <ada@...rsis.com>,
        "honghui.zhang@...iatek.com" <honghui.zhang@...iatek.com>,
        "linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "nagasureshkumarrelli@...il.com" <nagasureshkumarrelli@...il.com>
Subject: RE: [LINUX PATCH v9 2/4] memory: pl353: Add driver for arm pl353
 static memory controller

Hi Miquel,

Sorry for the late reply.
Currently I am addressing the comments that you gave to  pl353_nand driver.
And done with those, but this is pending.

> -----Original Message-----
> From: Miquel Raynal [mailto:miquel.raynal@...tlin.com]
> Sent: Thursday, June 7, 2018 9:37 PM
> To: Naga Sureshkumar Relli <nagasure@...inx.com>
> Cc: boris.brezillon@...tlin.com; richard@....at; wmw2@...radead.org;
> computersforpeace@...il.com; marek.vasut@...il.com; f.fainelli@...il.com;
> mmayer@...adcom.com; rogerq@...com; ladis@...ux-mips.org; ada@...rsis.com;
> honghui.zhang@...iatek.com; linux-mtd@...ts.infradead.org; linux-kernel@...r.kernel.org;
> nagasureshkumarrelli@...il.com
> Subject: Re: [LINUX PATCH v9 2/4] memory: pl353: Add driver for arm pl353 static
> memory controller
> 
> Hi Naga,
> 
> On Wed, 6 Jun 2018 13:19:40 +0530, Naga Sureshkumar Relli
> <naga.sureshkumar.relli@...inx.com> wrote:
> 
> > Add driver for arm pl353 static memory controller. This controller is
> > used in xilinx zynq soc for interfacing the nand and nor/sram memory
> > devices.
> 
> Upper case: Xilinx Zynq, SoC, NAND, NOR, SRAM.
Ok, I will update it in next version.

> 
> >
> > Signed-off-by: Naga Sureshkumar Relli
> > <naga.sureshkumar.relli@...inx.com>
> > ---
> > Changes in v9:
> >  - Addressed the comments given by Julia Cartwright to the v8 series.
> > Changes in v8:
> > - None
> > Changes in v7:
> > - Corrected the kconfig to use tristate selection
> > - Corrected the GPL licence ident
> > - Added boundary checks for nand timing parameters Changes in v6:
> > - Fixed checkpatch.pl reported warnings Changes in v5:
> > - Added pl353_smc_get_clkrate function, made pl353_smc_set_cycles as public
> >   API
> > - Removed nand timing parameter initialization and moved it to nand
> > driver Changes in v4:
> > - Modified driver to support multiple instances
> > - Used sleep instaed of busywait for delay Changes in v3:
> > - None
> > Changes in v2:
> > - Since now the timing parameters are in nano seconds, added logic to convert
> >   them to the cycles
> > ---
> >  drivers/memory/Kconfig                  |   8 +
> >  drivers/memory/Makefile                 |   1 +
> >  drivers/memory/pl353-smc.c              | 523
> ++++++++++++++++++++++++++++++++
> >  include/linux/platform_data/pl353-smc.h |  29 ++
> >  4 files changed, 561 insertions(+)
> >  create mode 100644 drivers/memory/pl353-smc.c  create mode 100644
> > include/linux/platform_data/pl353-smc.h
> >
> > diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig index
> > 19a0e83..9517da7 100644
> > --- a/drivers/memory/Kconfig
> > +++ b/drivers/memory/Kconfig
> > @@ -153,6 +153,14 @@ config DA8XX_DDRCTL
> >  	  Texas Instruments da8xx SoCs. It's used to tweak various memory
> >  	  controller configuration options.
> >
> > +config PL353_SMC
> > +	tristate "ARM PL35X Static Memory Controller(SMC) driver"
> > +	default y
> 
> This is not restricive at all. If this controller is only on a specific SoC, you should add another
> condition to compile the driver?
Can I add some thing like this?
depends on  ARCH_ZYNQ
depends on  ARM
> 
> > +	depends on ARM
> 
> Or here             ^
> 
> > +	help
> > +	  This driver is for the ARM PL351/PL353 Static Memory
> > +	  Controller(SMC) module.
> > +
> >  source "drivers/memory/samsung/Kconfig"
> >  source "drivers/memory/tegra/Kconfig"
> >
> > diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile index
> > 66f5524..58e794d 100644
> > --- a/drivers/memory/Makefile
> > +++ b/drivers/memory/Makefile
> > @@ -20,6 +20,7 @@ obj-$(CONFIG_TEGRA20_MC)	+= tegra20-mc.o
> >  obj-$(CONFIG_JZ4780_NEMC)	+= jz4780-nemc.o
> >  obj-$(CONFIG_MTK_SMI)		+= mtk-smi.o
> >  obj-$(CONFIG_DA8XX_DDRCTL)	+= da8xx-ddrctl.o
> > +obj-$(CONFIG_PL353_SMC)		+= pl353-smc.o
> >
> >  obj-$(CONFIG_SAMSUNG_MC)	+= samsung/
> >  obj-$(CONFIG_TEGRA_MC)		+= tegra/
> > diff --git a/drivers/memory/pl353-smc.c b/drivers/memory/pl353-smc.c
> > new file mode 100644 index 0000000..8758930
> > --- /dev/null
> > +++ b/drivers/memory/pl353-smc.c
> > @@ -0,0 +1,523 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * ARM PL353 SMC driver
> > + *
> > + * Copyright (C) 2012 Xilinx, Inc
> > + * Author: Punnaiah Choudary Kalluri <punnaiah@...inx.com>
> > + * Author: Naga Sureshkumar Relli <nagasure@...inx.com>
> > + *
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/io.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/slab.h>
> > +#include <linux/platform_data/pl353-smc.h>
> > +
> > +/* Register definitions */
> > +#define PL353_SMC_MEMC_STATUS_OFFS	0	/* Controller status reg, RO
> */
> > +#define PL353_SMC_CFG_CLR_OFFS		0xC	/* Clear config reg, WO */
> > +#define PL353_SMC_DIRECT_CMD_OFFS	0x10	/* Direct command reg, WO
> */
> > +#define PL353_SMC_SET_CYCLES_OFFS	0x14	/* Set cycles register, WO */
> > +#define PL353_SMC_SET_OPMODE_OFFS	0x18	/* Set opmode register, WO */
> > +#define PL353_SMC_ECC_STATUS_OFFS	0x400	/* ECC status register */
> > +#define PL353_SMC_ECC_MEMCFG_OFFS	0x404	/* ECC mem config reg */
> > +#define PL353_SMC_ECC_MEMCMD1_OFFS	0x408	/* ECC mem cmd1 reg */
> > +#define PL353_SMC_ECC_MEMCMD2_OFFS	0x40C	/* ECC mem cmd2 reg */
> > +#define PL353_SMC_ECC_VALUE0_OFFS	0x418	/* ECC value 0 reg */
> > +
> > +/* Controller status register specific constants */
> > +#define PL353_SMC_MEMC_STATUS_RAW_INT_1_SHIFT	6
> > +
> > +/* Clear configuration register specific constants */
> > +#define PL353_SMC_CFG_CLR_INT_CLR_1	0x10
> > +#define PL353_SMC_CFG_CLR_ECC_INT_DIS_1	0x40
> > +#define PL353_SMC_CFG_CLR_INT_DIS_1	0x2
> > +#define PL353_SMC_CFG_CLR_DEFAULT_MASK
> 	(PL353_SMC_CFG_CLR_INT_CLR_1 | \
> > +					 PL353_SMC_CFG_CLR_ECC_INT_DIS_1 | \
> > +					 PL353_SMC_CFG_CLR_INT_DIS_1)
> > +
> > +/* Set cycles register specific constants */
> > +#define PL353_SMC_SET_CYCLES_T0_MASK	0xF
> > +#define PL353_SMC_SET_CYCLES_T0_SHIFT	0
> > +#define PL353_SMC_SET_CYCLES_T1_MASK	0xF
> > +#define PL353_SMC_SET_CYCLES_T1_SHIFT	4
> > +#define PL353_SMC_SET_CYCLES_T2_MASK	0x7
> > +#define PL353_SMC_SET_CYCLES_T2_SHIFT	8
> > +#define PL353_SMC_SET_CYCLES_T3_MASK	0x7
> > +#define PL353_SMC_SET_CYCLES_T3_SHIFT	11
> > +#define PL353_SMC_SET_CYCLES_T4_MASK	0x7
> > +#define PL353_SMC_SET_CYCLES_T4_SHIFT	14
> > +#define PL353_SMC_SET_CYCLES_T5_MASK	0x7
> > +#define PL353_SMC_SET_CYCLES_T5_SHIFT	17
> > +#define PL353_SMC_SET_CYCLES_T6_MASK	0xF
> > +#define PL353_SMC_SET_CYCLES_T6_SHIFT	20
> > +
> > +/* ECC status register specific constants */
> > +#define PL353_SMC_ECC_STATUS_BUSY	BIT(6)
> > +
> > +/* ECC memory config register specific constants */
> > +#define PL353_SMC_ECC_MEMCFG_MODE_MASK	0xC
> > +#define PL353_SMC_ECC_MEMCFG_MODE_SHIFT	2
> > +#define PL353_SMC_ECC_MEMCFG_PGSIZE_MASK	0xC
> > +
> > +#define PL353_SMC_DC_UPT_NAND_REGS	((4 << 23) |	/* CS: NAND chip */
> \
> > +				 (2 << 21))	/* UpdateRegs operation */
> > +
> > +#define PL353_NAND_ECC_CMD1	((0x80)       |	/* Write command */ \
> > +				 (0 << 8)     |	/* Read command */ \
> > +				 (0x30 << 16) |	/* Read End command */ \
> > +				 (1 << 24))	/* Read End command calid */
> > +
> > +#define PL353_NAND_ECC_CMD2	((0x85)	      |	/* Write col change cmd */ \
> > +				 (5 << 8)     |	/* Read col change cmd */ \
> > +				 (0xE0 << 16) |	/* Read col change end cmd */ \
> > +				 (1 << 24)) /* Read col change end cmd valid */
> > +#define PL353_NAND_ECC_BUSY_TIMEOUT	(1 * HZ)
> > +/**
> > + * struct pl353_smc_data - Private smc driver structure
> > + * @devclk:		Pointer to the peripheral clock
> > + * @aperclk:		Pointer to the APER clock
> > + */
> > +struct pl353_smc_data {
> > +	struct clk		*memclk;
> > +	struct clk		*aclk;
> > +};
> > +
> > +/* SMC virtual register base */
> > +static void __iomem *pl353_smc_base;
> > +
> > +/**
> > + * pl353_smc_set_buswidth - Set memory buswidth
> > + * @bw:	Memory buswidth (8 | 16)
> > + * Return: 0 on success or negative errno.
> > + */
> > +int pl353_smc_set_buswidth(unsigned int bw) {
> > +	if (bw != PL353_SMC_MEM_WIDTH_8  && bw !=
> PL353_SMC_MEM_WIDTH_16)
> > +		return -EINVAL;
> > +
> > +	writel(bw, pl353_smc_base + PL353_SMC_SET_OPMODE_OFFS);
> > +	writel(PL353_SMC_DC_UPT_NAND_REGS, pl353_smc_base +
> > +	       PL353_SMC_DIRECT_CMD_OFFS);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(pl353_smc_set_buswidth);
> > +
> > +/**
> > + * pl353_smc_set_cycles - Set memory timing parameters
> > + * @t0:	t_rc		read cycle time
> > + * @t1:	t_wc		write cycle time
> > + * @t2:	t_rea/t_ceoe	output enable assertion delay
> > + * @t3:	t_wp		write enable deassertion delay
> > + * @t4:	t_clr/t_pc	page cycle time
> > + * @t5:	t_ar/t_ta	ID read time/turnaround time
> > + * @t6:	t_rr		busy to RE timing
> > + *
> > + * Sets NAND chip specific timing parameters.
> > + */
> > +static void pl353_smc_set_cycles(u32 t0, u32 t1, u32 t2, u32 t3, u32
> > +			      t4, u32 t5, u32 t6)
> > +{
> > +	t0 &= PL353_SMC_SET_CYCLES_T0_MASK;
> > +	t1 = (t1 & PL353_SMC_SET_CYCLES_T1_MASK) <<
> > +			PL353_SMC_SET_CYCLES_T1_SHIFT;
> > +	t2 = (t2 & PL353_SMC_SET_CYCLES_T2_MASK) <<
> > +			PL353_SMC_SET_CYCLES_T2_SHIFT;
> > +	t3 = (t3 & PL353_SMC_SET_CYCLES_T3_MASK) <<
> > +			PL353_SMC_SET_CYCLES_T3_SHIFT;
> > +	t4 = (t4 & PL353_SMC_SET_CYCLES_T4_MASK) <<
> > +			PL353_SMC_SET_CYCLES_T4_SHIFT;
> > +	t5 = (t5 & PL353_SMC_SET_CYCLES_T5_MASK) <<
> > +			PL353_SMC_SET_CYCLES_T5_SHIFT;
> > +	t6 = (t6 & PL353_SMC_SET_CYCLES_T6_MASK) <<
> > +			PL353_SMC_SET_CYCLES_T6_SHIFT;
> > +
> > +	t0 |= t1 | t2 | t3 | t4 | t5 | t6;
> > +
> > +	writel(t0, pl353_smc_base + PL353_SMC_SET_CYCLES_OFFS);
> > +	writel(PL353_SMC_DC_UPT_NAND_REGS, pl353_smc_base +
> > +	       PL353_SMC_DIRECT_CMD_OFFS);
> > +}
> > +
> > +/**
> > + * pl353_smc_ecc_is_busy - Read ecc busy flag
> > + * Return: the ecc_status bit from the ecc_status register. 1 = busy,
> > +0 = idle  */ int pl353_smc_ecc_is_busy(void) {
> > +	return !!(readl(pl353_smc_base + PL353_SMC_ECC_STATUS_OFFS) &
> > +		  PL353_SMC_ECC_STATUS_BUSY);
> 
> You can return a bool and avoid the '!!'.
Ok, I will update in next version.
> 
> > +}
> > +EXPORT_SYMBOL_GPL(pl353_smc_ecc_is_busy);
> > +
> > +/**
> > + * pl353_smc_get_ecc_val - Read ecc_valueN registers
> > + * @ecc_reg:	Index of the ecc_value reg (0..3)
> > + * Return: the content of the requested ecc_value register.
> > + *
> > + * There are four valid ecc_value registers. The argument is
> > +truncated to stay
> > + * within this valid boundary.
> > + */
> > +u32 pl353_smc_get_ecc_val(int ecc_reg) {
> > +	u32 addr, reg;
> > +
> > +	ecc_reg &= 3;
> 
> This is not readable. Please check for the validity of ecc_reg with standard '<' '>' operators.
Ok, I will change it.
> 
> > +	addr = PL353_SMC_ECC_VALUE0_OFFS + (ecc_reg << 2);
> 
> 2 should be defined
> 
> > +	reg = readl(pl353_smc_base + addr);
> > +
> > +	return reg;
> > +}
> > +EXPORT_SYMBOL_GPL(pl353_smc_get_ecc_val);
> > +
> > +/**
> > + * pl353_smc_get_nand_int_status_raw - Get NAND interrupt status bit
> > + * Return: the raw_int_status1 bit from the memc_status register
> 
> If you use kernel-doc format, should be "@return".
Ok, I will update it.
> 
> > + */
> > +int pl353_smc_get_nand_int_status_raw(void)
> > +{
> > +	u32 reg;
> > +
> > +	reg = readl(pl353_smc_base + PL353_SMC_MEMC_STATUS_OFFS);
> > +	reg >>= PL353_SMC_MEMC_STATUS_RAW_INT_1_SHIFT;
> > +	reg &= 1;
> > +
> > +	return reg;
> > +}
> > +EXPORT_SYMBOL_GPL(pl353_smc_get_nand_int_status_raw);
> > +
> > +/**
> > + * pl353_smc_clr_nand_int - Clear NAND interrupt  */ void
> > +pl353_smc_clr_nand_int(void) {
> > +	writel(PL353_SMC_CFG_CLR_INT_CLR_1,
> > +	       pl353_smc_base + PL353_SMC_CFG_CLR_OFFS); }
> > +EXPORT_SYMBOL_GPL(pl353_smc_clr_nand_int);
> > +
> > +/**
> > + * pl353_smc_set_ecc_mode - Set SMC ECC mode
> > + * @mode:	ECC mode (BYPASS, APB, MEM)
> > + * Return: 0 on success or negative errno.
> > + */
> > +int pl353_smc_set_ecc_mode(enum pl353_smc_ecc_mode mode)
> > +{
> > +	u32 reg;
> > +	int ret = 0;
> > +
> > +	switch (mode) {
> > +	case PL353_SMC_ECCMODE_BYPASS:
> > +	case PL353_SMC_ECCMODE_APB:
> > +	case PL353_SMC_ECCMODE_MEM:
> > +
> > +		reg = readl(pl353_smc_base + PL353_SMC_ECC_MEMCFG_OFFS);
> > +		reg &= ~PL353_SMC_ECC_MEMCFG_MODE_MASK;
> > +		reg |= mode << PL353_SMC_ECC_MEMCFG_MODE_SHIFT;
> > +		writel(reg, pl353_smc_base + PL353_SMC_ECC_MEMCFG_OFFS);
> > +
> > +		break;
> > +	default:
> > +		ret = -EINVAL;
> > +	}
> > +
> > +	return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(pl353_smc_set_ecc_mode);
> > +
> > +/**
> > + * pl353_smc_set_ecc_pg_size - Set SMC ECC page size
> > + * @pg_sz:	ECC page size
> > + * Return: 0 on success or negative errno.
> > + */
> > +int pl353_smc_set_ecc_pg_size(unsigned int pg_sz)
> > +{
> > +	u32 reg, sz;
> > +
> > +	switch (pg_sz) {
> > +	case 0:
> > +		sz = 0;
> > +		break;
> > +	case SZ_512:
> > +		sz = 1;
> > +		break;
> > +	case SZ_1K:
> > +		sz = 2;
> > +		break;
> > +	case SZ_2K:
> > +		sz = 3;
> > +		break;
> > +	default:
> > +		return -EINVAL;
> > +	}
> > +
> > +	reg = readl(pl353_smc_base + PL353_SMC_ECC_MEMCFG_OFFS);
> > +	reg &= ~PL353_SMC_ECC_MEMCFG_PGSIZE_MASK;
> > +	reg |= sz;
> > +	writel(reg, pl353_smc_base + PL353_SMC_ECC_MEMCFG_OFFS);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(pl353_smc_set_ecc_pg_size);
> > +
> > +static int __maybe_unused pl353_smc_suspend(struct device *dev)
> > +{
> > +	struct pl353_smc_data *pl353_smc = dev_get_drvdata(dev);
> > +
> > +	clk_disable(pl353_smc->memclk);
> > +	clk_disable(pl353_smc->aclk);
> 
> Are you sure you don't need to save any of the configured registers?
Yes
> 
> > +
> > +	return 0;
> > +}
> > +
> > +static int __maybe_unused pl353_smc_resume(struct device *dev)
> > +{
> > +	int ret;
> > +	struct pl353_smc_data *pl353_smc = dev_get_drvdata(dev);
> > +
> > +	ret = clk_enable(pl353_smc->aclk);
> > +	if (ret) {
> > +		dev_err(dev, "Cannot enable axi domain clock.\n");
> > +		return ret;
> > +	}
> > +
> > +	ret = clk_enable(pl353_smc->memclk);
> > +	if (ret) {
> > +		dev_err(dev, "Cannot enable memory clock.\n");
> > +		clk_disable(pl353_smc->aclk);
> > +		return ret;
> > +	}
> 
> New line
Ok, I will update
> 
> > +	return ret;
> > +}
> > +
> > +static SIMPLE_DEV_PM_OPS(pl353_smc_dev_pm_ops, pl353_smc_suspend,
> > +			 pl353_smc_resume);
> > +
> > +/**
> > + * pl353_smc_init_nand_interface - Initialize the NAND interface
> > + * @pdev:	Pointer to the platform_device struct
> > + * @nand_node:	Pointer to the pl353_nand device_node struct
> > + */
> > +static void pl353_smc_init_nand_interface(struct platform_device *pdev,
> > +					  struct device_node *nand_node)
> > +{
> > +	u32 t_rc, t_wc, t_rea, t_wp, t_clr, t_ar, t_rr;
> > +	int err;
> > +	unsigned long timeout = jiffies + PL353_NAND_ECC_BUSY_TIMEOUT;
> 
> Maybe this should be defined later in the code.
I will update in next version.
> 
> New line.
> 
> > +	/* nand-cycle-<X> property is refer to the NAND flash timing
> > +	 * mapping between dts and the NAND flash AC timing
> > +	 *  X  : AC timing name
> > +	 *  t0 : t_rc
> > +	 *  t1 : t_wc
> > +	 *  t2 : t_rea
> > +	 *  t3 : t_wp
> > +	 *  t4 : t_clr
> > +	 *  t5 : t_ar
> > +	 *  t6 : t_rr
> > +	 */
> > +	err = of_property_read_u32(nand_node, "arm,nand-cycle-t0", &t_rc);
> > +	if (err) {
> > +		dev_warn(&pdev->dev, "arm,nand-cycle-t0 not in device tree");
> > +		goto default_nand_timing;
> > +	}
> > +	err = of_property_read_u32(nand_node, "arm,nand-cycle-t1", &t_wc);
> > +	if (err) {
> > +		dev_warn(&pdev->dev, "arm,nand-cycle-t1 not in device tree");
> > +		goto default_nand_timing;
> > +	}
> > +	err = of_property_read_u32(nand_node, "arm,nand-cycle-t2", &t_rea);
> > +	if (err) {
> > +		dev_warn(&pdev->dev, "arm,nand-cycle-t2 not in device tree");
> > +		goto default_nand_timing;
> > +	}
> > +	err = of_property_read_u32(nand_node, "arm,nand-cycle-t3", &t_wp);
> > +	if (err) {
> > +		dev_warn(&pdev->dev, "arm,nand-cycle-t3 not in device tree");
> > +		goto default_nand_timing;
> > +	}
> > +	err = of_property_read_u32(nand_node, "arm,nand-cycle-t4", &t_clr);
> > +	if (err) {
> > +		dev_warn(&pdev->dev, "arm,nand-cycle-t4 not in device tree");
> > +		goto default_nand_timing;
> > +	}
> > +	err = of_property_read_u32(nand_node, "arm,nand-cycle-t5", &t_ar);
> > +	if (err) {
> > +		dev_warn(&pdev->dev, "arm,nand-cycle-t5 not in device tree");
> > +		goto default_nand_timing;
> > +	}
> > +	err = of_property_read_u32(nand_node, "arm,nand-cycle-t6", &t_rr);
> > +	if (err) {
> > +		dev_warn(&pdev->dev, "arm,nand-cycle-t6 not in device tree");
> > +		goto default_nand_timing;
> > +	}
> 
> See the comment in the bindings about this section.
Any way I am removing the above parameters reading as per your comment.
I will implement setup_data_interface() hook to get the timings. And this 
Applies to below comments as well.
> 
> > +
> > +default_nand_timing:
> > +	/*
> > +	 * Default assume 50MHz clock (20ns cycle time) and 3V operation
> > +	 * The SET_CYCLES_REG register value depends on the flash device.
> > +	 * Look in to the device datasheet and change its value, This value
> > +	 * is for 2Gb Numonyx flash.
> 
> No :)
> 
> The controller is not supposed to work with only one chip, right? So it
> should not embed any chip-specific information.
> 
> If this chip is not ONFI nor JEDEC and is not supported yet, the right
> way to do is to write a manufacturer driver.
> 
> > +	 */
> > +	if (err) {
> > +		/* set default NAND flash timing property */
> > +		dev_warn(&pdev->dev, "Using default timing for");
> > +		dev_warn(&pdev->dev, "2Gb Numonyx MT29F2G08ABAEAWP NAND
> flash");
> > +		dev_warn(&pdev->dev, "t_wp, t_clr, t_ar are set to 2");
> > +		dev_warn(&pdev->dev, "t_rc, t_wc, t_rr are set to 4");
> > +		dev_warn(&pdev->dev, "t_rea is set to 1");
> > +		t_rc = 4;
> > +		t_wc = 4;
> > +		t_rr = 4;
> > +		t_rea = 1;
> > +		t_wp = 2;
> > +		t_clr = 2;
> > +		t_ar = 2;
> > +	}
> > +
> > +	pl353_smc_set_buswidth(PL353_SMC_MEM_WIDTH_8);
> > +	pl353_smc_set_cycles(t_rc, t_wc, t_rea, t_wp, t_clr, t_ar, t_rr);
> > +	writel(PL353_SMC_CFG_CLR_INT_CLR_1,
> > +	       pl353_smc_base + PL353_SMC_CFG_CLR_OFFS);
> > +	writel(PL353_SMC_DC_UPT_NAND_REGS, pl353_smc_base +
> > +	       PL353_SMC_DIRECT_CMD_OFFS);
> > +	/* Wait till the ECC operation is complete */
> > +	do {
> > +		if (pl353_smc_ecc_is_busy())
> > +			cpu_relax();
> > +		else
> > +			break;
> > +	} while (!time_after_eq(jiffies, timeout));
> > +
> > +	if (time_after_eq(jiffies, timeout))
> > +		dev_err(&pdev->dev, "nand ecc busy status timed out");
> > +
> > +	writel(PL353_NAND_ECC_CMD1,
> > +	       pl353_smc_base + PL353_SMC_ECC_MEMCMD1_OFFS);
> > +	writel(PL353_NAND_ECC_CMD2,
> > +	       pl353_smc_base + PL353_SMC_ECC_MEMCMD2_OFFS);
> > +}
> > +
> > +static const struct of_device_id pl353_smc_supported_children[] = {
> > +	{ .compatible = "cfi-flash" },
> > +	{ .compatible = "arm,pl353-nand-r2p1",
> > +	.data = pl353_smc_init_nand_interface },
> 
> Please put the compatibles on another line and align data with them.
Ok, I will update it next version.

> 
> > +	{}
> > +};
> > +
> > +static int pl353_smc_probe(struct platform_device *pdev)
> > +{
> > +	struct pl353_smc_data *pl353_smc;
> > +	struct device_node *child;
> > +	struct resource *res;
> > +	int err;
> > +	struct device_node *of_node = pdev->dev.of_node;
> > +	void (*init)(struct platform_device *pdev,
> > +		     struct device_node *nand_node);
> > +	const struct of_device_id *match = NULL;
> > +
> > +	pl353_smc = devm_kzalloc(&pdev->dev, sizeof(*pl353_smc), GFP_KERNEL);
> > +	if (!pl353_smc)
> > +		return -ENOMEM;
> > +
> > +	/* Get the NAND controller virtual address */
> > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +	pl353_smc_base = devm_ioremap_resource(&pdev->dev, res);
> > +	if (IS_ERR(pl353_smc_base))
> > +		return PTR_ERR(pl353_smc_base);
> > +
> > +	pl353_smc->aclk = devm_clk_get(&pdev->dev, "aclk");
> > +	if (IS_ERR(pl353_smc->aclk)) {
> > +		dev_err(&pdev->dev, "aclk clock not found.\n");
> > +		return PTR_ERR(pl353_smc->aclk);
> > +	}
> > +
> > +	pl353_smc->memclk = devm_clk_get(&pdev->dev, "memclk");
> > +	if (IS_ERR(pl353_smc->memclk)) {
> > +		dev_err(&pdev->dev, "memclk clock not found.\n");
> > +		return PTR_ERR(pl353_smc->memclk);
> > +	}
> > +
> > +	err = clk_prepare_enable(pl353_smc->aclk);
> > +	if (err) {
> > +		dev_err(&pdev->dev, "Unable to enable AXI clock.\n");
> > +		return err;
> > +	}
> > +
> > +	err = clk_prepare_enable(pl353_smc->memclk);
> > +	if (err) {
> > +		dev_err(&pdev->dev, "Unable to enable memory clock.\n");
> > +		goto out_clk_dis_aper;
> > +	}
> > +
> > +	platform_set_drvdata(pdev, pl353_smc);
> > +
> > +	/* clear interrupts */
> > +	writel(PL353_SMC_CFG_CLR_DEFAULT_MASK,
> > +	       pl353_smc_base + PL353_SMC_CFG_CLR_OFFS);
> > +
> > +	/* Find compatible children. Only a single child is supported */
> > +	for_each_available_child_of_node(of_node, child) {
> > +		match = of_match_node(pl353_smc_supported_children, child);
> > +		if (!match) {
> > +			dev_warn(&pdev->dev, "unsupported child node\n");
> > +			continue;
> > +		}
> > +		break;
> > +	}
> > +	if (!match) {
> > +		dev_err(&pdev->dev, "no matching children\n");
> > +		goto out_clk_disable;
> > +	}
> > +
> > +	init = match->data;
> > +	if (init)
> > +		init(pdev, child);
> > +	of_platform_device_create(child, NULL, &pdev->dev);
> > +
> > +	return 0;
> > +
> > +out_clk_disable:
> > +	clk_disable_unprepare(pl353_smc->memclk);
> > +out_clk_dis_aper:
> > +	clk_disable_unprepare(pl353_smc->aclk);
> > +
> > +	return err;
> > +}
> > +
> > +static int pl353_smc_remove(struct platform_device *pdev)
> > +{
> > +	struct pl353_smc_data *pl353_smc = platform_get_drvdata(pdev);
> > +
> > +	clk_disable_unprepare(pl353_smc->memclk);
> > +	clk_disable_unprepare(pl353_smc->aclk);
> > +
> > +	return 0;
> > +}
> > +
> > +/* Match table for device tree binding */
> > +static const struct of_device_id pl353_smc_of_match[] = {
> > +	{ .compatible = "arm,pl353-smc-r2p1" },
> > +	{ },
> > +};
> > +MODULE_DEVICE_TABLE(of, pl353_smc_of_match);
> > +
> > +static struct platform_driver pl353_smc_driver = {
> > +	.probe		= pl353_smc_probe,
> > +	.remove		= pl353_smc_remove,
> > +	.driver		= {
> > +		.name	= "pl353-smc",
> > +		.pm	= &pl353_smc_dev_pm_ops,
> > +		.of_match_table = pl353_smc_of_match,
> > +	},
> > +};
> > +
> > +module_platform_driver(pl353_smc_driver);
> > +
> > +MODULE_AUTHOR("Xilinx, Inc.");
> > +MODULE_DESCRIPTION("ARM PL353 SMC Driver");
> > +MODULE_LICENSE("GPL");
> > diff --git a/include/linux/platform_data/pl353-smc.h b/include/linux/platform_data/pl353-
> smc.h
> 
> I don't think you really need a separate file for these enums? Unless
> it is really platform specific?
The issue here is I have to include this in pl353_nand driver.
And I just referred " include/linux/platform_data/mtd-nand-pxa3xx.h", hence
I added like this.
> 
> > new file mode 100644
> > index 0000000..fc4129e
> > --- /dev/null
> > +++ b/include/linux/platform_data/pl353-smc.h
> > @@ -0,0 +1,29 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * ARM PL353 SMC Driver Header
> > + *
> > + * Copyright (C) 2017 Xilinx, Inc
> > + */
> > +
> > +#ifndef __LINUX_MEMORY_PL353_SMC_H
> > +#define __LINUX_MEMORY_PL353_SMC_H
> > +
> > +enum pl353_smc_ecc_mode {
> > +	PL353_SMC_ECCMODE_BYPASS = 0,
> > +	PL353_SMC_ECCMODE_APB = 1,
> > +	PL353_SMC_ECCMODE_MEM = 2
> > +};
> > +
> > +enum pl353_smc_mem_width {
> > +	PL353_SMC_MEM_WIDTH_8 = 0,
> > +	PL353_SMC_MEM_WIDTH_16 = 1
> > +};
> > +
> > +u32 pl353_smc_get_ecc_val(int ecc_reg);
> > +int pl353_smc_ecc_is_busy(void);
> > +int pl353_smc_get_nand_int_status_raw(void);
> > +void pl353_smc_clr_nand_int(void);
> > +int pl353_smc_set_ecc_mode(enum pl353_smc_ecc_mode mode);
> > +int pl353_smc_set_ecc_pg_size(unsigned int pg_sz);
> > +int pl353_smc_set_buswidth(unsigned int bw);
> > +#endif
> 
> Thanks,
> Miquèl
> 
> --
> Miquel Raynal, Bootlin (formerly Free Electrons)
> Embedded Linux and Kernel engineering
> https://bootlin.com

Thanks,
Naga Sureshkumar Relli

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