memory: ti-aemif: introduce AEMIF driver

Add new AEMIF driver for EMIF16 Texas Instruments 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 4 chip selects with 64M byte access
per chip select.

Synchronous memories such as DDR1 SD RAM, SDR SDRAM and Mobile SDR
are not supported.

This controller is used on SoCs like Davinci, Keysone2

Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/memory/Kconfig

@@ -7,6 +7,17 @@ menuconfig MEMORY
 
 if MEMORY
 
+config TI_AEMIF
+	tristate "Texas Instruments AEMIF driver"
+	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

drivers/memory/Makefile

@@ -5,6 +5,7 @@
 ifeq ($(CONFIG_DDR),y)
 obj-$(CONFIG_OF)		+= of_memory.o
 endif
+obj-$(CONFIG_TI_AEMIF)		+= ti-aemif.o
 obj-$(CONFIG_TI_EMIF)		+= emif.o
 obj-$(CONFIG_FSL_IFC)		+= fsl_ifc.o
 obj-$(CONFIG_MVEBU_DEVBUS)	+= mvebu-devbus.o

drivers/memory/ti-aemif.c

@@ -0,0 +1,427 @@
+/*
+ * TI AEMIF driver
+ *
+ * Copyright (C) 2010 - 2013 Texas Instruments Incorporated. http://www.ti.com/
+ *
+ * Authors:
+ * Murali Karicheri <m-karicheri2@ti.com>
+ * Ivan Khoronzhuk <ivan.khoronzhuk@ti.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)
+
+/**
+ * struct aemif_cs_data: 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 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;
+};
+
+/**
+ * struct aemif_device: 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_offset: start number of cs nodes
+ * @cs_data: array of chip-select settings
+ */
+struct aemif_device {
+	void __iomem *base;
+	struct clk *clk;
+	unsigned long clk_rate;
+	u8 num_cs;
+	int cs_offset;
+	struct aemif_cs_data cs_data[NUM_CS];
+};
+
+/**
+ * aemif_calc_rate - calculate timing data.
+ * @pdev: platform device to calculate for
+ * @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 aemif_calc_rate(struct platform_device *pdev, int wanted,
+			   unsigned long clk, int max)
+{
+	int result;
+
+	result = DIV_ROUND_UP((wanted * clk), NSEC_PER_MSEC) - 1;
+
+	dev_dbg(&pdev->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;
+}
+
+/**
+ * aemif_config_abus - configure async bus parameters
+ * @pdev: platform device to configure for
+ * @csnum: aemif chip select number
+ *
+ * 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 aemif_config_abus(struct platform_device *pdev, int csnum)
+{
+	struct aemif_device *aemif = platform_get_drvdata(pdev);
+	struct aemif_cs_data *data = &aemif->cs_data[csnum];
+	int ta, rhold, rstrobe, rsetup, whold, wstrobe, wsetup;
+	unsigned long clk_rate = aemif->clk_rate;
+	unsigned offset;
+	u32 set, val;
+
+	offset = A1CR_OFFSET + (data->cs - aemif->cs_offset) * 4;
+
+	ta	= aemif_calc_rate(pdev, data->ta, clk_rate, TA_MAX);
+	rhold	= aemif_calc_rate(pdev, data->rhold, clk_rate, RHOLD_MAX);
+	rstrobe	= aemif_calc_rate(pdev, data->rstrobe, clk_rate, RSTROBE_MAX);
+	rsetup	= aemif_calc_rate(pdev, data->rsetup, clk_rate, RSETUP_MAX);
+	whold	= aemif_calc_rate(pdev, data->whold, clk_rate, WHOLD_MAX);
+	wstrobe	= aemif_calc_rate(pdev, data->wstrobe, clk_rate, WSTROBE_MAX);
+	wsetup	= aemif_calc_rate(pdev, data->wsetup, clk_rate, WSETUP_MAX);
+
+	if (ta < 0 || rhold < 0 || rstrobe < 0 || rsetup < 0 ||
+	    whold < 0 || wstrobe < 0 || wsetup < 0) {
+		dev_err(&pdev->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;
+}
+
+static inline int aemif_cycles_to_nsec(int val, unsigned long clk_rate)
+{
+	return ((val + 1) * NSEC_PER_MSEC) / clk_rate;
+}
+
+/**
+ * aemif_get_hw_params - function to read hw register values
+ * @pdev: platform device to read for
+ * @csnum: aemif chip select number
+ *
+ * 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 aemif_get_hw_params(struct platform_device *pdev, int csnum)
+{
+	struct aemif_device *aemif = platform_get_drvdata(pdev);
+	struct aemif_cs_data *data = &aemif->cs_data[csnum];
+	unsigned long clk_rate = aemif->clk_rate;
+	u32 val, offset;
+
+	offset = A1CR_OFFSET + (data->cs - aemif->cs_offset) * 4;
+	val = readl(aemif->base + offset);
+
+	data->ta = aemif_cycles_to_nsec(TA_VAL(val), clk_rate);
+	data->rhold = aemif_cycles_to_nsec(RHOLD_VAL(val), clk_rate);
+	data->rstrobe = aemif_cycles_to_nsec(RSTROBE_VAL(val), clk_rate);
+	data->rsetup = aemif_cycles_to_nsec(RSETUP_VAL(val), clk_rate);
+	data->whold = aemif_cycles_to_nsec(WHOLD_VAL(val), clk_rate);
+	data->wstrobe = aemif_cycles_to_nsec(WSTROBE_VAL(val), clk_rate);
+	data->wsetup = aemif_cycles_to_nsec(WSETUP_VAL(val), clk_rate);
+	data->enable_ew = EW_VAL(val);
+	data->enable_ss = SS_VAL(val);
+	data->asize = val & ASIZE_MAX;
+}
+
+/**
+ * of_aemif_parse_abus_config - parse CS configuration from DT
+ * @pdev: platform device to parse for
+ * @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_aemif_parse_abus_config(struct platform_device *pdev,
+				      struct device_node *np)
+{
+	struct aemif_device *aemif = platform_get_drvdata(pdev);
+	struct aemif_cs_data *data;
+	u32 cs;
+	u32 val;
+
+	if (of_property_read_u32(np, "ti,cs-chipselect", &cs)) {
+		dev_dbg(&pdev->dev, "cs property is required");
+		return -EINVAL;
+	}
+
+	if (cs - aemif->cs_offset >= NUM_CS || cs < aemif->cs_offset) {
+		dev_dbg(&pdev->dev, "cs number is incorrect %d", cs);
+		return -EINVAL;
+	}
+
+	if (aemif->num_cs >= NUM_CS) {
+		dev_dbg(&pdev->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 */
+	aemif_get_hw_params(pdev, aemif->num_cs++);
+
+	/* override the values from device node */
+	if (!of_property_read_u32(np, "ti,cs-min-turnaround-ns", &val))
+		data->ta = val;
+
+	if (!of_property_read_u32(np, "ti,cs-read-hold-ns", &val))
+		data->rhold = val;
+
+	if (!of_property_read_u32(np, "ti,cs-read-strobe-ns", &val))
+		data->rstrobe = val;
+
+	if (!of_property_read_u32(np, "ti,cs-read-setup-ns", &val))
+		data->rsetup = val;
+
+	if (!of_property_read_u32(np, "ti,cs-write-hold-ns", &val))
+		data->whold = val;
+
+	if (!of_property_read_u32(np, "ti,cs-write-strobe-ns", &val))
+		data->wstrobe = val;
+
+	if (!of_property_read_u32(np, "ti,cs-write-setup-ns", &val))
+		data->wsetup = val;
+
+	if (!of_property_read_u32(np, "ti,cs-bus-width", &val))
+		if (val == 16)
+			data->asize = 1;
+	data->enable_ew = of_property_read_bool(np, "ti,cs-extended-wait-mode");
+	data->enable_ss = of_property_read_bool(np, "ti,cs-select-strobe-mode");
+	return 0;
+}
+
+static const struct of_device_id aemif_of_match[] = {
+	{ .compatible = "ti,davinci-aemif", },
+	{ .compatible = "ti,da850-aemif", },
+	{},
+};
+
+static int aemif_probe(struct platform_device *pdev)
+{
+	int i;
+	int ret = -ENODEV;
+	struct resource *res;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct device_node *child_np;
+	struct aemif_device *aemif;
+
+	if (np == NULL)
+		return 0;
+
+	aemif = devm_kzalloc(dev, sizeof(*aemif), GFP_KERNEL);
+	if (!aemif)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, aemif);
+
+	aemif->clk = devm_clk_get(dev, 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) / MSEC_PER_SEC;
+
+	if (of_device_is_compatible(np, "ti,da850-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_available_child_of_node(np, child_np) {
+		ret = of_aemif_parse_abus_config(pdev, child_np);
+		if (ret < 0)
+			goto error;
+	}
+
+	for (i = 0; i < aemif->num_cs; i++) {
+		ret = aemif_config_abus(pdev, 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_available_child_of_node(np, child_np) {
+		ret = of_platform_populate(child_np, NULL, NULL, dev);
+		if (ret < 0)
+			goto error;
+	}
+
+	return 0;
+error:
+	clk_disable_unprepare(aemif->clk);
+	return ret;
+}
+
+static int aemif_remove(struct platform_device *pdev)
+{
+	struct aemif_device *aemif = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(aemif->clk);
+	return 0;
+}
+
+static struct platform_driver aemif_driver = {
+	.probe = aemif_probe,
+	.remove = aemif_remove,
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.owner = THIS_MODULE,
+		.of_match_table = of_match_ptr(aemif_of_match),
+	},
+};
+
+module_platform_driver(aemif_driver);
+
+MODULE_AUTHOR("Murali Karicheri <m-karicheri2@ti.com>");
+MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>");
+MODULE_DESCRIPTION("Texas Instruments AEMIF driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" KBUILD_MODNAME);