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Message-ID: <5294DE17.9080900@ti.com>
Date: Tue, 26 Nov 2013 19:44:55 +0200
From: "ivan.khoronzhuk" <ivan.khoronzhuk@...com>
To: Sekhar Nori <nsekhar@...com>,
"Shilimkar, Santosh" <santosh.shilimkar@...com>,
Rob Landley <rob@...dley.net>,
Russell King <linux@....linux.org.uk>
CC: Mark Rutland <mark.rutland@....com>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"Strashko, Grygorii" <grygorii.strashko@...com>,
Pawel Moll <pawel.moll@....com>,
Stephen Warren <swarren@...dotorg.org>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...nel.crashing.org>,
Rob Herring <rob.herring@...xeda.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 07/12] memory: davinci-aemif: introduce AEMIF driver
On 11/26/2013 09:20 AM, Sekhar Nori wrote:
> On Monday 11 November 2013 10:36 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@...com>
>> ---
>> 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
>> + bool "Texas Instruments DaVinci AEMIF driver"
>
> This driver cannot be a module? If not, why not?
>
Yes it can be a module, I will correct it.
>> + 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-$(CONFIG_TI_DAVINCI_AEMIF) += davinci-aemif.o
>> obj-$(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
>> + *
>> + * Copyright (C) 2010 - 2013 Texas Instruments Incorporated. http://www.ti.com/
>> + * Copyright (C) Heiko Schocher <hs@...x.de>
>> + * Copyright (C) Ivan Khoronzhuk <ivan.khoronzhuk@...com>
>
> Just checking: You meant Author: ? Code is already copyrighted to TI by
> line above.
>
It will be
Author:
Heiko Schocher <hs@...x.de>
Ivan Khoronzhuk <ivan.khoronzhuk@...com>
>> + *
>> + * 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"
>> +
>> +/**
>> + * 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;
>> +};
>> +
>> +/**
>> + * structure to hold device data
>> + * @base: base address of AEMIF registers
>> + * @clk: source clock
>> + * @clk_rate: clock's rate in kHz
>> + * @num_cs: number of assigned chip-selects
>> + * @cs_data: array of chip-select settings
>> + */
>> +struct davinci_aemif_device {
>> + struct device *dev;
>> + void __iomem *base;
>> + struct clk *clk;
>> + unsigned long clk_rate;
>> + u8 num_cs;
>> + int cs_offset;
>> + struct davinci_aemif_cs_data cs_data[NUM_CS];
>> +};
>> +
>> +static struct davinci_aemif_device *aemif;
>> +/**
>> + * davinci_aemif_calc_rate - calculate timing data.
>> + * @wanted: The cycle time needed in nanoseconds.
>> + * @clk: The input clock rate in kHz.
>> + * @max: The maximum divider value that can be programmed.
>> + *
>> + * On success, returns the calculated timing value minus 1 for easy
>> + * programming into AEMIF timing registers, else negative errno.
>> + */
>> +static int davinci_aemif_calc_rate(int wanted, unsigned long clk, int max)
>> +{
>> + int result;
>> +
>> + result = DIV_ROUND_UP((wanted * clk), NSEC_PER_MSEC) - 1;
>> +
>> + dev_dbg(aemif->dev, "%s: result %d from %ld, %d\n", __func__, result,
>> + clk, wanted);
>> +
>> + /* It is generally OK to have a more relaxed timing than requested... */
>> + if (result < 0)
>> + result = 0;
>> +
>> + /* ... But configuring tighter timings is not an option. */
>> + else if (result > max)
>> + result = -EINVAL;
>> +
>> + return result;
>> +}
>> +
>> +/**
>> + * davinci_aemif_config_abus - configure async bus parameters
>> + * @data: aemif chip select configuration
>> + *
>> + * This function programs the given timing values (in real clock) into the
>> + * AEMIF registers taking the AEMIF clock into account.
>> + *
>> + * This function does not use any locking while programming the AEMIF
>> + * because it is expected that there is only one user of a given
>> + * chip-select.
>> + *
>> + * Returns 0 on success, else negative errno.
>> + */
>> +static int davinci_aemif_config_abus(struct davinci_aemif_cs_data *data)
>> +{
>> + int ta, rhold, rstrobe, rsetup, whold, wstrobe, wsetup;
>> + unsigned offset;
>> + u32 set, val;
>> +
>> + offset = A1CR_OFFSET + (data->cs - aemif->cs_offset) * 4;
>> +
>> + ta = davinci_aemif_calc_rate(data->ta, aemif->clk_rate, TA_MAX);
>> + rhold = davinci_aemif_calc_rate(data->rhold, aemif->clk_rate,
>> + RHOLD_MAX);
>> + rstrobe = davinci_aemif_calc_rate(data->rstrobe, aemif->clk_rate,
>> + RSTROBE_MAX);
>> + rsetup = davinci_aemif_calc_rate(data->rsetup, aemif->clk_rate,
>> + RSETUP_MAX);
>> + whold = davinci_aemif_calc_rate(data->whold, aemif->clk_rate,
>> + WHOLD_MAX);
>> + wstrobe = davinci_aemif_calc_rate(data->wstrobe, aemif->clk_rate,
>> + WSTROBE_MAX);
>> + wsetup = davinci_aemif_calc_rate(data->wsetup, aemif->clk_rate,
>> + WSETUP_MAX);
>> +
>> + if (ta < 0 || rhold < 0 || rstrobe < 0 || rsetup < 0 ||
>> + whold < 0 || wstrobe < 0 || wsetup < 0) {
>> + dev_err(aemif->dev, "%s: cannot get suitable timings\n",
>> + __func__);
>> + return -EINVAL;
>> + }
>> +
>> + set = TA(ta) | RHOLD(rhold) | RSTROBE(rstrobe) | RSETUP(rsetup) |
>> + WHOLD(whold) | WSTROBE(wstrobe) | WSETUP(wsetup);
>> +
>> + set |= (data->asize & ACR_ASIZE_MASK);
>> + if (data->enable_ew)
>> + set |= ACR_EW_MASK;
>> + if (data->enable_ss)
>> + set |= ACR_SS_MASK;
>> +
>> + val = readl(aemif->base + offset);
>> + val &= ~CONFIG_MASK;
>> + val |= set;
>> + writel(val, aemif->base + offset);
>> +
>> + return 0;
>> +}
>> +
>> +inline int davinci_aemif_cycles_to_nsec(int val)
>> +{
>> + return ((val + 1) * NSEC_PER_MSEC) / aemif->clk_rate;
>> +}
>> +
>> +/**
>> + * davinci_aemif_get_hw_params - function to read hw register values
>> + * @data: ptr to cs data
>> + *
>> + * This function reads the defaults from the registers and update
>> + * the timing values. Required for get/set commands and also for
>> + * the case when driver needs to use defaults in hardware.
>> + */
>> +static void davinci_aemif_get_hw_params(struct davinci_aemif_cs_data *data)
>> +{
>> + u32 val, offset;
>> + offset = A1CR_OFFSET + (data->cs - aemif->cs_offset) * 4;
>> +
>> + val = readl(aemif->base + offset);
>> + data->ta = davinci_aemif_cycles_to_nsec(TA_VAL(val));
>> + data->rhold = davinci_aemif_cycles_to_nsec(RHOLD_VAL(val));
>> + data->rstrobe = davinci_aemif_cycles_to_nsec(RSTROBE_VAL(val));
>> + data->rsetup = davinci_aemif_cycles_to_nsec(RSETUP_VAL(val));
>> + data->whold = davinci_aemif_cycles_to_nsec(WHOLD_VAL(val));
>> + data->wstrobe = davinci_aemif_cycles_to_nsec(WSTROBE_VAL(val));
>> + data->wsetup = davinci_aemif_cycles_to_nsec(WSETUP_VAL(val));
>> + data->enable_ew = EW_VAL(val);
>> + data->enable_ss = SS_VAL(val);
>> + data->asize = val & ASIZE_MAX;
>> +}
>> +
>> +/**
>> + * of_davinci_aemif_parse_abus_config - parse CS configuration from DT
>> + * @np: device node ptr
>> + *
>> + * This function update the emif async bus configuration based on the values
>> + * configured in a cs device binding node.
>> + */
>> +static int of_davinci_aemif_parse_abus_config(struct device_node *np)
>> +{
>> + struct davinci_aemif_cs_data *data;
>> + unsigned long cs;
>> + u32 val;
>> +
>> + if (kstrtoul(np->name + 2, 10, &cs) < 0) {
>> + dev_dbg(aemif->dev, "cs name is incorrect");
>> + return -EINVAL;
>> + }
>> +
>> + if (cs - aemif->cs_offset >= NUM_CS || cs < aemif->cs_offset) {
>> + dev_dbg(aemif->dev, "cs number is incorrect %lu", cs);
>> + return -EINVAL;
>> + }
>> +
>> + if (aemif->num_cs >= NUM_CS) {
>> + dev_dbg(aemif->dev, "cs count is more than %d", NUM_CS);
>> + return -EINVAL;
>> + }
>> +
>> + data = &aemif->cs_data[aemif->num_cs++];
>> + data->cs = cs;
>> +
>> + /* read the current value in the hw register */
>> + davinci_aemif_get_hw_params(data);
>> +
>> + /* override the values from device node */
>> + of_property_read_u8(np, "ti,davinci-cs-ta", &data->ta);
>> + of_property_read_u8(np, "ti,davinci-cs-rhold", &data->rhold);
>> + of_property_read_u16(np, "ti,davinci-cs-rstrobe", &data->rstrobe);
>> + of_property_read_u8(np, "ti,davinci-cs-rsetup", &data->rsetup);
>> + of_property_read_u8(np, "ti,davinci-cs-whold", &data->whold);
>> + of_property_read_u16(np, "ti,davinci-cs-wstrobe", &data->wstrobe);
>> + of_property_read_u8(np, "ti,davinci-cs-wsetup", &data->wsetup);
>> + if (!of_property_read_u32(np, "ti,bus-width", &val))
>> + if (val == 16)
>> + data->asize = 1;
>> + data->enable_ew = of_property_read_bool(np, "ti,davinci-cs-ew");
>> + data->enable_ss = of_property_read_bool(np, "ti,davinci-cs-ss");
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id davinci_aemif_of_match[] = {
>> + { .compatible = "ti,davinci-aemif", },
>> + { .compatible = "ti,keystone-aemif", },
>> + { .compatible = "ti,omap-L138-aemif", },
>
> Please use ti,da850-aemif instead. We dont use the omap-like paper part
> number for these devices in kernel to avoid confusion with real OMAP
> devices.
>
Ok, I'll replace ti,omap-L138-aemif -> ti,da850-aemif
>> + {},
>> +};
>> +
>> +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;
>> + }
>
> Why expressly prevent multiple AEMIF devices? Its entirely conceivable
> to have two memories like NAND and NOR flash connect to two different
> AEMIF interfaces.
>
It can be, but I'm not sure if it is needed. Currently I've not seen case where
more than 2 cses were used, I mean we have 2 cs free, why do we need the second AEMIF
controller?
>> +
>> + aemif = devm_kzalloc(dev, sizeof(*aemif), GFP_KERNEL);
>> +
>> + if (!aemif) {
>> + dev_err(dev, "cannot allocate memory for aemif\n");
>> + return -ENOMEM;
>> + }
>> +
>> + aemif->clk = devm_clk_get(dev, "aemif");
>
> If this is the only clock you care about, you can use NULL for
> connection id.
>
Yes I can, I'll replace aemif name on NULL.
>> + 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;
>> +
>> + aemif->dev = dev;
>> +
>> + if (of_device_is_compatible(np, "ti,omap-L138-aemif"))
>> + aemif->cs_offset = 2;
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + aemif->base = devm_ioremap_resource(dev, res);
>> + if (IS_ERR(aemif->base)) {
>> + ret = PTR_ERR(aemif->base);
>> + goto error;
>> + }
>> +
>> + /*
>> + * For every controller device node, there is a cs device node that
>> + * describe the bus configuration parameters. This functions iterate
>> + * over these nodes and update the cs data array.
>> + */
>> + for_each_matching_node(np, of_match_ptr(davinci_cs_of_match)) {
>> + ret = of_davinci_aemif_parse_abus_config(np);
>> + if (ret < 0)
>> + goto error;
>> + }
>> +
>> + for (i = 0; i < aemif->num_cs; i++) {
>> + ret = davinci_aemif_config_abus(&aemif->cs_data[i]);
>> + if (ret < 0) {
>> + dev_err(dev, "Error configuring chip select %d\n",
>> + aemif->cs_data[i].cs);
>> + goto error;
>> + }
>> + }
>> +
>> + /*
>> + * Create a child devices explicitly from here to
>> + * guarantee that the child will be probed after the AEMIF timing
>> + * parameters are set.
>> + */
>> + for_each_matching_node(np, of_match_ptr(davinci_cs_of_match)) {
>> + ret = of_platform_populate(np, NULL, NULL, dev);
>> + if (ret < 0)
>> + goto error;
>> + }
>> +
>> + return 0;
>> +error:
>> + clk_disable_unprepare(aemif->clk);
>> + return ret;
>> +}
>> +
>> +static int davinci_aemif_remove(struct platform_device *pdev)
>> +{
>> + clk_disable_unprepare(aemif->clk);
>> + return 0;
>> +}
>> +
>> +static struct platform_driver davinci_aemif_driver = {
>> + .probe = davinci_aemif_probe,
>> + .remove = davinci_aemif_remove,
>> + .driver = {
>> + .name = DRV_NAME,
>> + .owner = THIS_MODULE,
>> + .of_match_table = of_match_ptr(davinci_aemif_of_match),
>> + },
>> +};
>> +
>> +module_platform_driver(davinci_aemif_driver);
>> +
>> +MODULE_AUTHOR("Murali Karicheri <m-karicheri2@...com>");
>
> Is this correct? If yes, I would have expected him to sign-off on the
> patch too. If not, please drop this.
I will add sign-off
>
> Thanks,
> Sekhar
>
--
Regards,
Ivan Khoronzhuk
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