Re: [PATCH 07/12] memory: davinci-aemif: introduce AEMIF driver
From: Sekhar Nori
Date: Tue Nov 26 2013 - 02:22:26 EST
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@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
> + bool "Texas Instruments DaVinci AEMIF driver"
This driver cannot be a module? If not, why not?
> + 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@xxxxxxx>
> + * Copyright (C) Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxx>
Just checking: You meant Author: ? Code is already copyrighted to TI by
line above.
> + *
> + * 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.
> + {},
> +};
> +
> +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.
> +
> + 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.
> + 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@xxxxxx>");
Is this correct? If yes, I would have expected him to sign-off on the
patch too. If not, please drop this.
Thanks,
Sekhar
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