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

From: [email-masked] (ivan.khoronzhuk)
Date: Mon, 18 Nov 2013 21:15:35 +0200

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 <[email-masked]>
>> ---
>>   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 <[email-masked]>
>> + * Copyright (C) Ivan Khoronzhuk <[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.
>> + */
>> +
>> +#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