Re: [PATCH 07/12] memory: davinci-aemif: introduce AEMIF driver

From: ivan.khoronzhuk
Date: Mon Nov 18 2013 - 14:17:18 EST

On 11/12/2013 06:08 PM, Santosh Shilimkar wrote:
> + Greg KH (drivers/memory/* patches goes through his queue)
>
> On Monday 11 November 2013 12:06 PM, Khoronzhuk, Ivan wrote:
>> Add new AEMIF driver for EMIF16 davinci controller. The EMIF16 module
>> is intended to provide a glue-less interface to a variety of
>> asynchronous memory devices like ASRA M, NOR and NAND memory. A total
>> of 256M bytes of any of these memories can be accessed at any given
>> time via four chip selects with 64M byte access per chip select.
>>
>> Synchronous memories such as DDR1 SD RAM, SDR SDRAM and Mobile SDR
>> are not supported.
>>
>> See http://www.ti.com/lit/ug/sprugz3a/sprugz3a.pdf
>>
>> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxx>
>> ---
>> drivers/memory/Kconfig | 11 ++
>> drivers/memory/Makefile | 1 +
>> drivers/memory/davinci-aemif.c | 415 ++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 427 insertions(+)
>> create mode 100644 drivers/memory/davinci-aemif.c
>>
>> diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig
>> index 29a11db..010e75e 100644
>> --- a/drivers/memory/Kconfig
>> +++ b/drivers/memory/Kconfig
>> @@ -7,6 +7,17 @@ menuconfig MEMORY
>>
>> if MEMORY
>>
>> +config TI_DAVINCI_AEMIF
> s/TI_DAVINCI_AEMIF/TI_AEMIF
>

Ok

>> + bool "Texas Instruments DaVinci AEMIF driver"
> Drop DaVinci above since its used on more SOCs.
>> + depends on (ARCH_DAVINCI || ARCH_KEYSTONE) && OF
>> + help
>> + This driver is for the AEMIF module available in Texas Instruments
>> + SoCs. AEMIF stands for Asynchronous External Memory Interface and
>> + is intended to provide a glue-less interface to a variety of
>> + asynchronuous memory devices like ASRAM, NOR and NAND memory. A total
>> + of 256M bytes of any of these memories can be accessed at a given
>> + time via four chip selects with 64M byte access per chip select.
>> +
>> config TI_EMIF
>> tristate "Texas Instruments EMIF driver"
>> depends on ARCH_OMAP2PLUS
>> diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
>> index 969d923..af14126 100644
>> --- a/drivers/memory/Makefile
>> +++ b/drivers/memory/Makefile
>> @@ -5,6 +5,7 @@
>> ifeq ($(CONFIG_DDR),y)
>> obj-$(CONFIG_OF) += of_memory.o
>> endif
>> +obj-$(CONFIG_TI_DAVINCI_AEMIF) += davinci-aemif.o
>
> Change this accordingly once the config is renamed.
>

Ok

>> obj-$(CONFIG_TI_EMIF) += emif.o
>> obj-$(CONFIG_MVEBU_DEVBUS) += mvebu-devbus.o
>> obj-$(CONFIG_TEGRA20_MC) += tegra20-mc.o
>> diff --git a/drivers/memory/davinci-aemif.c b/drivers/memory/davinci-aemif.c
>> new file mode 100644
>> index 0000000..e36b74b
>> --- /dev/null
>> +++ b/drivers/memory/davinci-aemif.c
>> @@ -0,0 +1,415 @@
>> +/*
>> + * DaVinci/Keystone AEMIF driver
> s/{DaVinci/Keystone}/TI
>> + *
>> + * Copyright (C) 2010 - 2013 Texas Instruments Incorporated. http://www.ti.com/
>> + * Copyright (C) Heiko Schocher <hs@xxxxxxx>
>> + * Copyright (C) Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxx>
>> + *
>> + * 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.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/err.h>
>> +#include <linux/io.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/of_platform.h>
>> +#include <linux/platform_device.h>
>> +
>> +#define TA_SHIFT 2
>> +#define RHOLD_SHIFT 4
>> +#define RSTROBE_SHIFT 7
>> +#define RSETUP_SHIFT 13
>> +#define WHOLD_SHIFT 17
>> +#define WSTROBE_SHIFT 20
>> +#define WSETUP_SHIFT 26
>> +#define EW_SHIFT 30
>> +#define SS_SHIFT 31
>> +
>> +#define TA(x) ((x) << TA_SHIFT)
>> +#define RHOLD(x) ((x) << RHOLD_SHIFT)
>> +#define RSTROBE(x) ((x) << RSTROBE_SHIFT)
>> +#define RSETUP(x) ((x) << RSETUP_SHIFT)
>> +#define WHOLD(x) ((x) << WHOLD_SHIFT)
>> +#define WSTROBE(x) ((x) << WSTROBE_SHIFT)
>> +#define WSETUP(x) ((x) << WSETUP_SHIFT)
>> +#define EW(x) ((x) << EW_SHIFT)
>> +#define SS(x) ((x) << SS_SHIFT)
>> +
>> +#define ASIZE_MAX 0x1
>> +#define TA_MAX 0x3
>> +#define RHOLD_MAX 0x7
>> +#define RSTROBE_MAX 0x3f
>> +#define RSETUP_MAX 0xf
>> +#define WHOLD_MAX 0x7
>> +#define WSTROBE_MAX 0x3f
>> +#define WSETUP_MAX 0xf
>> +#define EW_MAX 0x1
>> +#define SS_MAX 0x1
>> +#define NUM_CS 4
>> +
>> +#define TA_VAL(x) (((x) & TA(TA_MAX)) >> TA_SHIFT)
>> +#define RHOLD_VAL(x) (((x) & RHOLD(RHOLD_MAX)) >> RHOLD_SHIFT)
>> +#define RSTROBE_VAL(x) (((x) & RSTROBE(RSTROBE_MAX)) >> RSTROBE_SHIFT)
>> +#define RSETUP_VAL(x) (((x) & RSETUP(RSETUP_MAX)) >> RSETUP_SHIFT)
>> +#define WHOLD_VAL(x) (((x) & WHOLD(WHOLD_MAX)) >> WHOLD_SHIFT)
>> +#define WSTROBE_VAL(x) (((x) & WSTROBE(WSTROBE_MAX)) >> WSTROBE_SHIFT)
>> +#define WSETUP_VAL(x) (((x) & WSETUP(WSETUP_MAX)) >> WSETUP_SHIFT)
>> +#define EW_VAL(x) (((x) & EW(EW_MAX)) >> EW_SHIFT)
>> +#define SS_VAL(x) (((x) & SS(SS_MAX)) >> SS_SHIFT)
>> +
>> +#define NRCSR_OFFSET 0x00
>> +#define AWCCR_OFFSET 0x04
>> +#define A1CR_OFFSET 0x10
>> +
>> +#define ACR_ASIZE_MASK 0x3
>> +#define ACR_EW_MASK BIT(30)
>> +#define ACR_SS_MASK BIT(31)
>> +#define ASIZE_16BIT 1
>> +
>> +#define CONFIG_MASK (TA(TA_MAX) | \
>> + RHOLD(RHOLD_MAX) | \
>> + RSTROBE(RSTROBE_MAX) | \
>> + RSETUP(RSETUP_MAX) | \
>> + WHOLD(WHOLD_MAX) | \
>> + WSTROBE(WSTROBE_MAX) | \
>> + WSETUP(WSETUP_MAX) | \
>> + EW(EW_MAX) | SS(SS_MAX) | \
>> + ASIZE_MAX)
>> +
>> +#define DRV_NAME "davinci-aemif"
> s/davinci-aemif/ti-aemif

Ok

>> +
>> +/**
>> + * structure to hold cs parameters
>> + * @cs: chip-select number
>> + * @wstrobe: write strobe width, ns
>> + * @rstrobe: read strobe width, ns
>> + * @wsetup: write setup width, ns
>> + * @whold: write hold width, ns
>> + * @rsetup: read setup width, ns
>> + * @rhold: read hold width, ns
>> + * @ta: minimum turn around time, ns
>> + * @enable_ss: enable/disable select strobe mode
>> + * @enable_ew: enable/disable extended wait mode
>> + * @asize: width of the asynchronous device's data bus
>> + */
>> +struct davinci_aemif_cs_data {
>> + u8 cs;
>> + u16 wstrobe;
>> + u16 rstrobe;
>> + u8 wsetup;
>> + u8 whold;
>> + u8 rsetup;
>> + u8 rhold;
>> + u8 ta;
>> + u8 enable_ss;
>> + u8 enable_ew;
>> + u8 asize;
>> +};
>> +
> I suggest you drop davinci prefix throughout the
> driver.
>
> [..]
>

Seems there is nothing to prevent
Ok

>> +static const struct of_device_id davinci_aemif_of_match[] = {
>> + { .compatible = "ti,davinci-aemif", },
>> + { .compatible = "ti,keystone-aemif", },
>> + { .compatible = "ti,omap-L138-aemif", },
>> + {},
>> +};
> Do we need three seperate compatible or "ti,aemif" should
> be enough ? Are there differences which we need to handled
> based on compatibles ?
>

We need separate compatibles. Depending on this cs start number is evaluated.
For omap-L138-aemif it is 2 for keystone-aemif it is 0.

>> +
>> +static const struct of_device_id davinci_cs_of_match[] = {
>> + { .compatible = "ti,davinci-cs", },
>> + {},
>> +};
>> +
>> +static int davinci_aemif_probe(struct platform_device *pdev)
>> +{
>> + int ret = -ENODEV, i;
>> + struct resource *res;
>> + struct device *dev = &pdev->dev;
>> + struct device_node *np = dev->of_node;
>> +
>> + if (np == NULL)
>> + return 0;
>> +
>> + if (aemif) {
>> + dev_err(dev, "davinci_aemif driver is in use currently\n");
>> + return -EBUSY;
>> + }
>> +
>> + aemif = devm_kzalloc(dev, sizeof(*aemif), GFP_KERNEL);
>> +
> Drop this extra line.
>

Ok, I will

>> + if (!aemif) {
>> + dev_err(dev, "cannot allocate memory for aemif\n");
>> + return -ENOMEM;
>> + }
>> +
>> + aemif->clk = devm_clk_get(dev, "aemif");
>> + if (IS_ERR(aemif->clk)) {
>> + dev_err(dev, "cannot get clock 'aemif'\n");
>> + return PTR_ERR(aemif->clk);
>> + }
>> +
>> + clk_prepare_enable(aemif->clk);
>> + aemif->clk_rate = clk_get_rate(aemif->clk) / 1000;
>> +
> 1000 divider ? Define a marco and use it to be clear.

Is it OK if I use MSEC_PER_SEC (linux/time.h).

>
> Other than above comments patch looks fine to me.
>
> Regards,
> Santosh
>


--
Regards,
Ivan Khoronzhuk
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