[RFC PATCH 1/2] memory: davinci - add aemif controller platform driver
Murali Karicheri
m-karicheri2 at ti.com
Fri Nov 2 12:21:17 EDT 2012
This is a platform driver for asynchronous external memory interface
available on TI SoCs. This driver was previously located inside the
mach-davinci folder. As this DaVinci IP is re-used across multiple
family of devices such as c6x, keystone etc, the driver is moved to drivers.
The driver configures async bus parameters associated with a particular
chip select. For DaVinci controller driver and driver for other async
devices such as NOR flash, ASRAM etc, the bus confuguration is
done by this driver at init time. A set of APIs (set/get) provided to
update the values based on specific driver usage.
Signed-off-by: Murali Karicheri <m-karicheri2 at ti.com>
---
.../devicetree/bindings/arm/davinci/aemif.txt | 62 +++
drivers/memory/Kconfig | 10 +
drivers/memory/Makefile | 1 +
drivers/memory/davinci-aemif.c | 397 ++++++++++++++++++++
include/linux/platform_data/davinci-aemif.h | 47 +++
5 files changed, 517 insertions(+)
create mode 100644 Documentation/devicetree/bindings/arm/davinci/aemif.txt
create mode 100644 drivers/memory/davinci-aemif.c
create mode 100644 include/linux/platform_data/davinci-aemif.h
diff --git a/Documentation/devicetree/bindings/arm/davinci/aemif.txt b/Documentation/devicetree/bindings/arm/davinci/aemif.txt
new file mode 100644
index 0000000..7d70d42
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/davinci/aemif.txt
@@ -0,0 +1,62 @@
+* Texas Instruments Davinci AEMIF bus interface
+
+This file provides information for the davinci-emif chip select
+bindings.
+
+This is a sub device node inside the davinci-emif device node
+to describe a async bus for a specific chip select. For NAND,
+CFI flash device bindings described inside an aemif node,
+etc, a cs sub node is defined to associate the bus parameter
+bindings used by the device.
+
+Required properties:=
+- compatible: "ti,davinci-cs";
+- #address-cells = <1>;
+- #size-cells = <1>;
+- cs - cs used by the device (NAND, CFI flash etc. values in the range: 2-5
+
+Optional properties:-
+- asize - asynchronous data bus width (0 - 8bit, 1 - 16 bit)
+ All of the params below in nanoseconds
+
+- ta - Minimum turn around time
+- rhold - read hold width
+- rstobe - read strobe width
+- rsetup - read setup width
+- whold - write hold width
+- wstrobe - write strobe width
+- wsetup - write setup width
+- ss - enable/disable select strobe (0 - disable, 1 - enable)
+- ew - enable/disable extended wait cycles (0 - disable, 1 - enable)
+
+Example for davinci nand chip select
+
+aemif at 60000000 {
+
+ compatible = "ti,davinci-aemif";
+ #address-cells = <2>;
+ #size-cells = <1>;
+
+ nand_cs:cs2 at 70000000 {
+ compatible = "ti,davinci-cs";
+ #address-cells = <1>;
+ #size-cells = <1>;
+ cs = <2>;
+ asize = <1>;
+ ta = <24>;
+ rhold = <48>;
+ rstrobe = <390>;
+ rsetup = <96>;
+ whold = <48>;
+ wstrobe = <390>;
+ wsetup = <96>;
+ };
+
+ nand at 2,0 {
+
+ ....
+
+ };
+};
+
+
diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig
index 067f311..2636a95 100644
--- a/drivers/memory/Kconfig
+++ b/drivers/memory/Kconfig
@@ -40,4 +40,14 @@ config TEGRA30_MC
analysis, especially for IOMMU/SMMU(System Memory Management
Unit) module.
+config TI_DAVINCI_AEMIF
+ bool "Texas Instruments DaVinci AEMIF driver"
+ 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.
+
endif
diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
index 42b3ce9..246aa61 100644
--- a/drivers/memory/Makefile
+++ b/drivers/memory/Makefile
@@ -5,3 +5,4 @@
obj-$(CONFIG_TI_EMIF) += emif.o
obj-$(CONFIG_TEGRA20_MC) += tegra20-mc.o
obj-$(CONFIG_TEGRA30_MC) += tegra30-mc.o
+obj-$(CONFIG_TI_DAVINCI_AEMIF) += davinci-aemif.o
diff --git a/drivers/memory/davinci-aemif.c b/drivers/memory/davinci-aemif.c
new file mode 100644
index 0000000..6c42116
--- /dev/null
+++ b/drivers/memory/davinci-aemif.c
@@ -0,0 +1,397 @@
+/*
+ * AEMIF support for DaVinci SoCs
+ *
+ * Copyright (C) 2010 Texas Instruments Incorporated. http://www.ti.com/
+ * Copyright (C) Heiko Schocher <hs at denx.de>
+ *
+ * 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_address.h>
+#include <linux/platform_data/davinci-aemif.h>
+#include <linux/platform_device.h>
+#include <linux/time.h>
+
+/* Timing value configuration */
+#define TA(x) ((x) << 2)
+#define RHOLD(x) ((x) << 4)
+#define RSTROBE(x) ((x) << 7)
+#define RSETUP(x) ((x) << 13)
+#define WHOLD(x) ((x) << 17)
+#define WSTROBE(x) ((x) << 20)
+#define WSETUP(x) ((x) << 26)
+#define EW(x) ((x) << 30)
+#define SS(x) ((x) << 31)
+
+#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 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"
+
+struct aemif_device {
+ struct davinci_aemif_pdata *cfg;
+ void __iomem *base;
+ struct clk *clk;
+};
+
+static struct aemif_device *aemif;
+/**
+ * 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 aemif_calc_rate(int wanted, unsigned long clk, int max)
+{
+ int result;
+
+ result = DIV_ROUND_UP((wanted * clk), NSEC_PER_MSEC) - 1;
+
+ pr_debug("%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 given
+ * AEMIF interface
+ * @cs: chip-select to program the timing values for
+ * @data: aemif chip select configuration
+ * @base: aemif io mapped configuration base
+ *
+ * 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(unsigned int cs,
+ void __iomem *base,
+ struct davinci_aemif_cs_data *data)
+{
+ int ta, rhold, rstrobe, rsetup, whold, wstrobe, wsetup;
+ unsigned offset = A1CR_OFFSET + cs * 4;
+ unsigned long clkrate;
+ unsigned set, val;
+
+ if (!data)
+ return -EINVAL;
+
+ clkrate = clk_get_rate(aemif->clk);
+
+ clkrate /= 1000; /* turn clock into kHz for ease of use */
+
+ ta = aemif_calc_rate(data->ta, clkrate, TA_MAX);
+ rhold = aemif_calc_rate(data->rhold, clkrate, RHOLD_MAX);
+ rstrobe = aemif_calc_rate(data->rstrobe, clkrate, RSTROBE_MAX);
+ rsetup = aemif_calc_rate(data->rsetup, clkrate, RSETUP_MAX);
+ whold = aemif_calc_rate(data->whold, clkrate, WHOLD_MAX);
+ wstrobe = aemif_calc_rate(data->wstrobe, clkrate, WSTROBE_MAX);
+ wsetup = aemif_calc_rate(data->wsetup, clkrate, WSETUP_MAX);
+
+ if (ta < 0 || rhold < 0 || rstrobe < 0 || rsetup < 0 ||
+ whold < 0 || wstrobe < 0 || wsetup < 0) {
+ pr_err("%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;
+}
+
+/**
+ * get_cs_data - helper function to get bus configuration data for a given cs
+ * @cs: chip-select, values 2-5
+ */
+static struct davinci_aemif_cs_data *get_cs_data(int cs)
+{
+ int i;
+
+ for (i = 0; i < aemif->cfg->num_cs; i++) {
+ if (cs == aemif->cfg->cs_data[i].cs)
+ break;
+ }
+
+ if (i == aemif->cfg->num_cs)
+ return NULL;
+
+ return &aemif->cfg->cs_data[i];
+}
+
+/**
+ * davinci_aemif_set_abus_params - Set bus configuration data for a given cs
+ * @cs: chip-select, values 2-5
+ * @data: ptr to a struct to hold the configuration data to be set
+ *
+ * This function is called to configure emif bus parameters for a given cs.
+ * Users call this function after calling davinci_aemif_get_abus_params()
+ * to get current parameters, modify and call this function
+ */
+int davinci_aemif_set_abus_params(unsigned int cs,
+ struct davinci_aemif_cs_data *data)
+{
+ struct davinci_aemif_cs_data *curr_cs_data;
+ int ret = -EINVAL, chip_cs;
+
+ if (data == NULL)
+ return ret;
+
+ if (aemif->base == NULL)
+ return ret;
+
+ /* translate to chip CS which starts at 2 */
+ chip_cs = cs + 2;
+
+ curr_cs_data = get_cs_data(chip_cs);
+ if (curr_cs_data) {
+ ret = davinci_aemif_config_abus(chip_cs, aemif->base, data);
+ if (!ret) {
+ *curr_cs_data = *data;
+ return 0;
+ }
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(davinci_aemif_set_abus_params);
+
+/**
+ * davinci_aemif_get_abus_params - Get bus configuration data for a given cs
+ * @cs: chip-select, values 2-5
+ * returns: ptr to a struct having the current configuration data
+ */
+struct davinci_aemif_cs_data *davinci_aemif_get_abus_params(unsigned int cs)
+{
+ /* translate to chip CS which starts at 2 */
+ return get_cs_data(cs + 2);
+}
+EXPORT_SYMBOL(davinci_aemif_get_abus_params);
+
+#if defined(CONFIG_OF)
+/**
+ * dv_get_value - helper function to read a attribute valye
+ * @np: device node ptr
+ * @name: name of the attribute
+ * returns: value of the attribute
+ */
+static int dv_get_value(struct device_node *np, const char *name)
+{
+ u32 data;
+ int ret;
+
+ ret = of_property_read_u32(np, name, &data);
+ if (ret != 0)
+ return ret;
+
+ return data;
+}
+
+/**
+ * of_davinci_aemif_parse_abus_config - parse bus config data from a cs node
+ * @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;
+ int cs;
+
+
+ cs = dv_get_value(np, "cs");
+ if (cs < 2 || cs >= NUM_CS)
+ return -EINVAL;
+
+ if (aemif->cfg->num_cs >= NUM_CS)
+ return -EINVAL;
+
+ data = &aemif->cfg->cs_data[aemif->cfg->num_cs++];
+ data->cs = cs;
+ data->ta = dv_get_value(np, "ta");
+ data->rhold = dv_get_value(np, "rhold");
+ data->rstrobe = dv_get_value(np, "rstrobe");
+ data->rsetup = dv_get_value(np, "rsetup");
+ data->whold = dv_get_value(np, "whold");
+ data->wstrobe = dv_get_value(np, "wstrobe");
+ data->wsetup = dv_get_value(np, "wsetup");
+ data->asize = dv_get_value(np, "asize");
+ data->enable_ew = dv_get_value(np, "ew");
+ data->enable_ss = dv_get_value(np, "ss");
+ return 0;
+}
+#endif
+
+static const struct of_device_id davinci_aemif_of_match[] __devinitconst = {
+ { .compatible = "ti,davinci-aemif", },
+ {},
+};
+
+static const struct of_device_id davinci_cs_of_match[] __devinitconst = {
+ { .compatible = "ti,davinci-cs", },
+ {},
+};
+
+/**
+ * of_davinci_aemif_cs_init - init cs data based on cs device nodes
+ * @np: device node ptr
+ *
+ * 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.
+ */
+static int of_davinci_aemif_cs_init(struct device_node *aemif_np)
+{
+ struct device_node *np = aemif_np;
+
+ if (!np)
+ return -ENODEV;
+
+ for_each_matching_node(np, davinci_cs_of_match)
+ of_davinci_aemif_parse_abus_config(np);
+ return 0;
+}
+
+static int __devinit davinci_aemif_probe(struct platform_device *pdev)
+{
+ struct davinci_aemif_pdata *cfg;
+ int ret = -ENODEV, i;
+ struct resource *res;
+
+ aemif = devm_kzalloc(&pdev->dev, sizeof(*aemif), GFP_KERNEL);
+
+ if (!aemif)
+ return -ENOMEM;
+
+ aemif->clk = clk_get(NULL, "aemif");
+ if (IS_ERR(aemif->clk))
+ return PTR_ERR(aemif->clk);
+
+ clk_prepare_enable(aemif->clk);
+
+ if (pdev->dev.platform_data == NULL) {
+ /* Not platform data, we get the cs data from the cs nodes */
+ cfg = devm_kzalloc(&pdev->dev, sizeof(*cfg), GFP_KERNEL);
+ if (cfg == NULL)
+ return -ENOMEM;
+
+ aemif->cfg = cfg;
+ if (of_davinci_aemif_cs_init(pdev->dev.of_node) < 0) {
+ pr_err("No platform data or cs of node present\n");
+ goto error;
+ }
+ } else {
+ cfg = pdev->dev.platform_data;
+ aemif->cfg = cfg;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ pr_err("No IO memory address defined\n");
+ goto error;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ aemif->base = devm_request_and_ioremap(&pdev->dev, res);
+ if (!aemif->base) {
+ ret = -EBUSY;
+ pr_err("ioremap failed\n");
+ goto error;
+ }
+
+ for (i = 0; i < cfg->num_cs; i++) {
+ ret = davinci_aemif_config_abus(cfg->cs_data[i].cs,
+ aemif->base, &cfg->cs_data[i]);
+ if (ret < 0) {
+ pr_err("Error configuring chip select %d\n",
+ cfg->cs_data[i].cs);
+ goto error;
+ }
+ }
+ return ret;
+error:
+ clk_disable_unprepare(aemif->clk);
+ clk_put(aemif->clk);
+ return ret;
+}
+
+static struct platform_driver davinci_aemif_driver = {
+ .probe = davinci_aemif_probe,
+ .driver = {
+ .name = DRV_NAME,
+ .owner = THIS_MODULE,
+ .of_match_table = davinci_aemif_of_match,
+ },
+};
+
+static int __init davinci_aemif_init(void)
+{
+ return platform_driver_register(&davinci_aemif_driver);
+}
+subsys_initcall(davinci_aemif_init);
+
+static void __exit davinci_aemif_exit(void)
+{
+ clk_disable_unprepare(aemif->clk);
+ clk_put(aemif->clk);
+ platform_driver_unregister(&davinci_aemif_driver);
+}
+module_exit(davinci_aemif_exit);
+
+MODULE_AUTHOR("Murali Karicheri <m-karicheri2 at ti.com>");
+MODULE_DESCRIPTION("Texas Instruments AEMIF driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRV_NAME);
diff --git a/include/linux/platform_data/davinci-aemif.h b/include/linux/platform_data/davinci-aemif.h
new file mode 100644
index 0000000..03f3ad0
--- /dev/null
+++ b/include/linux/platform_data/davinci-aemif.h
@@ -0,0 +1,47 @@
+/*
+ * TI DaVinci AEMIF support
+ *
+ * Copyright 2010 (C) Texas Instruments, Inc. http://www.ti.com/
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+#ifndef _MACH_DAVINCI_AEMIF_H
+#define _MACH_DAVINCI_AEMIF_H
+
+#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
+
+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;
+};
+
+struct davinci_aemif_pdata {
+ u8 num_cs;
+ struct davinci_aemif_cs_data cs_data[4];
+};
+
+/* API to Get current Asynchrnous emif bus parameters */
+struct davinci_aemif_cs_data *davinci_aemif_get_abus_params(unsigned int cs);
+
+/* API to Set current Asynchrnous emif bus parameters */
+int davinci_aemif_set_abus_params(unsigned int cs,
+ struct davinci_aemif_cs_data *data);
+#endif
--
1.7.9.5
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