/*
* 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", },
{},
};
MODULE_DEVICE_TABLE(of, aemif_of_match);
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,
.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);
