linux/drivers/memory/mvebu-devbus.c
Thomas Petazzoni 0456d3300e memory: mvebu-devbus: add a devbus, keep-config property
Currently, the mvebu-devbus Device Tree binding makes defining the
timing parameters mandatory.

However, in practice, when converting Orion5x platforms to the Device
Tree, we may not necessarily have easy access to the hardware
platforms to fetch those values which were not defined in old-style
board files: all these platforms rely on the bootloader setting the
timing parameters correctly.

In order to facilitate the migration to the Device Tree of this
platform, this commit relaxes the mvebu-devbus Device Tree binding by
introducing a 'devbus,keep-config' boolean property, which, if
defined, will ignore all timing parameters passed in the Device Tree,
and simply rely on the timing values already defined by the
bootloader.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Link: https://lkml.kernel.org/r/1398202002-28530-10-git-send-email-thomas.petazzoni@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
2014-04-29 13:17:10 +00:00

363 lines
9.9 KiB
C

/*
* Marvell EBU SoC Device Bus Controller
* (memory controller for NOR/NAND/SRAM/FPGA devices)
*
* Copyright (C) 2013-2014 Marvell
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/mbus.h>
#include <linux/of_platform.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
/* Register definitions */
#define ARMADA_DEV_WIDTH_SHIFT 30
#define ARMADA_BADR_SKEW_SHIFT 28
#define ARMADA_RD_HOLD_SHIFT 23
#define ARMADA_ACC_NEXT_SHIFT 17
#define ARMADA_RD_SETUP_SHIFT 12
#define ARMADA_ACC_FIRST_SHIFT 6
#define ARMADA_SYNC_ENABLE_SHIFT 24
#define ARMADA_WR_HIGH_SHIFT 16
#define ARMADA_WR_LOW_SHIFT 8
#define ARMADA_READ_PARAM_OFFSET 0x0
#define ARMADA_WRITE_PARAM_OFFSET 0x4
#define ORION_RESERVED (0x2 << 30)
#define ORION_BADR_SKEW_SHIFT 28
#define ORION_WR_HIGH_EXT_BIT BIT(27)
#define ORION_WR_HIGH_EXT_MASK 0x8
#define ORION_WR_LOW_EXT_BIT BIT(26)
#define ORION_WR_LOW_EXT_MASK 0x8
#define ORION_ALE_WR_EXT_BIT BIT(25)
#define ORION_ALE_WR_EXT_MASK 0x8
#define ORION_ACC_NEXT_EXT_BIT BIT(24)
#define ORION_ACC_NEXT_EXT_MASK 0x10
#define ORION_ACC_FIRST_EXT_BIT BIT(23)
#define ORION_ACC_FIRST_EXT_MASK 0x10
#define ORION_TURN_OFF_EXT_BIT BIT(22)
#define ORION_TURN_OFF_EXT_MASK 0x8
#define ORION_DEV_WIDTH_SHIFT 20
#define ORION_WR_HIGH_SHIFT 17
#define ORION_WR_HIGH_MASK 0x7
#define ORION_WR_LOW_SHIFT 14
#define ORION_WR_LOW_MASK 0x7
#define ORION_ALE_WR_SHIFT 11
#define ORION_ALE_WR_MASK 0x7
#define ORION_ACC_NEXT_SHIFT 7
#define ORION_ACC_NEXT_MASK 0xF
#define ORION_ACC_FIRST_SHIFT 3
#define ORION_ACC_FIRST_MASK 0xF
#define ORION_TURN_OFF_SHIFT 0
#define ORION_TURN_OFF_MASK 0x7
struct devbus_read_params {
u32 bus_width;
u32 badr_skew;
u32 turn_off;
u32 acc_first;
u32 acc_next;
u32 rd_setup;
u32 rd_hold;
};
struct devbus_write_params {
u32 sync_enable;
u32 wr_high;
u32 wr_low;
u32 ale_wr;
};
struct devbus {
struct device *dev;
void __iomem *base;
unsigned long tick_ps;
};
static int get_timing_param_ps(struct devbus *devbus,
struct device_node *node,
const char *name,
u32 *ticks)
{
u32 time_ps;
int err;
err = of_property_read_u32(node, name, &time_ps);
if (err < 0) {
dev_err(devbus->dev, "%s has no '%s' property\n",
name, node->full_name);
return err;
}
*ticks = (time_ps + devbus->tick_ps - 1) / devbus->tick_ps;
dev_dbg(devbus->dev, "%s: %u ps -> 0x%x\n",
name, time_ps, *ticks);
return 0;
}
static int devbus_get_timing_params(struct devbus *devbus,
struct device_node *node,
struct devbus_read_params *r,
struct devbus_write_params *w)
{
int err;
err = of_property_read_u32(node, "devbus,bus-width", &r->bus_width);
if (err < 0) {
dev_err(devbus->dev,
"%s has no 'devbus,bus-width' property\n",
node->full_name);
return err;
}
/*
* The bus width is encoded into the register as 0 for 8 bits,
* and 1 for 16 bits, so we do the necessary conversion here.
*/
if (r->bus_width == 8)
r->bus_width = 0;
else if (r->bus_width == 16)
r->bus_width = 1;
else {
dev_err(devbus->dev, "invalid bus width %d\n", r->bus_width);
return -EINVAL;
}
err = get_timing_param_ps(devbus, node, "devbus,badr-skew-ps",
&r->badr_skew);
if (err < 0)
return err;
err = get_timing_param_ps(devbus, node, "devbus,turn-off-ps",
&r->turn_off);
if (err < 0)
return err;
err = get_timing_param_ps(devbus, node, "devbus,acc-first-ps",
&r->acc_first);
if (err < 0)
return err;
err = get_timing_param_ps(devbus, node, "devbus,acc-next-ps",
&r->acc_next);
if (err < 0)
return err;
if (of_device_is_compatible(devbus->dev->of_node, "marvell,mvebu-devbus")) {
err = get_timing_param_ps(devbus, node, "devbus,rd-setup-ps",
&r->rd_setup);
if (err < 0)
return err;
err = get_timing_param_ps(devbus, node, "devbus,rd-hold-ps",
&r->rd_hold);
if (err < 0)
return err;
err = of_property_read_u32(node, "devbus,sync-enable",
&w->sync_enable);
if (err < 0) {
dev_err(devbus->dev,
"%s has no 'devbus,sync-enable' property\n",
node->full_name);
return err;
}
}
err = get_timing_param_ps(devbus, node, "devbus,ale-wr-ps",
&w->ale_wr);
if (err < 0)
return err;
err = get_timing_param_ps(devbus, node, "devbus,wr-low-ps",
&w->wr_low);
if (err < 0)
return err;
err = get_timing_param_ps(devbus, node, "devbus,wr-high-ps",
&w->wr_high);
if (err < 0)
return err;
return 0;
}
static void devbus_orion_set_timing_params(struct devbus *devbus,
struct device_node *node,
struct devbus_read_params *r,
struct devbus_write_params *w)
{
u32 value;
/*
* The hardware designers found it would be a good idea to
* split most of the values in the register into two fields:
* one containing all the low-order bits, and another one
* containing just the high-order bit. For all of those
* fields, we have to split the value into these two parts.
*/
value = (r->turn_off & ORION_TURN_OFF_MASK) << ORION_TURN_OFF_SHIFT |
(r->acc_first & ORION_ACC_FIRST_MASK) << ORION_ACC_FIRST_SHIFT |
(r->acc_next & ORION_ACC_NEXT_MASK) << ORION_ACC_NEXT_SHIFT |
(w->ale_wr & ORION_ALE_WR_MASK) << ORION_ALE_WR_SHIFT |
(w->wr_low & ORION_WR_LOW_MASK) << ORION_WR_LOW_SHIFT |
(w->wr_high & ORION_WR_HIGH_MASK) << ORION_WR_HIGH_SHIFT |
r->bus_width << ORION_DEV_WIDTH_SHIFT |
((r->turn_off & ORION_TURN_OFF_EXT_MASK) ? ORION_TURN_OFF_EXT_BIT : 0) |
((r->acc_first & ORION_ACC_FIRST_EXT_MASK) ? ORION_ACC_FIRST_EXT_BIT : 0) |
((r->acc_next & ORION_ACC_NEXT_EXT_MASK) ? ORION_ACC_NEXT_EXT_BIT : 0) |
((w->ale_wr & ORION_ALE_WR_EXT_MASK) ? ORION_ALE_WR_EXT_BIT : 0) |
((w->wr_low & ORION_WR_LOW_EXT_MASK) ? ORION_WR_LOW_EXT_BIT : 0) |
((w->wr_high & ORION_WR_HIGH_EXT_MASK) ? ORION_WR_HIGH_EXT_BIT : 0) |
(r->badr_skew << ORION_BADR_SKEW_SHIFT) |
ORION_RESERVED;
writel(value, devbus->base);
}
static void devbus_armada_set_timing_params(struct devbus *devbus,
struct device_node *node,
struct devbus_read_params *r,
struct devbus_write_params *w)
{
u32 value;
/* Set read timings */
value = r->bus_width << ARMADA_DEV_WIDTH_SHIFT |
r->badr_skew << ARMADA_BADR_SKEW_SHIFT |
r->rd_hold << ARMADA_RD_HOLD_SHIFT |
r->acc_next << ARMADA_ACC_NEXT_SHIFT |
r->rd_setup << ARMADA_RD_SETUP_SHIFT |
r->acc_first << ARMADA_ACC_FIRST_SHIFT |
r->turn_off;
dev_dbg(devbus->dev, "read parameters register 0x%p = 0x%x\n",
devbus->base + ARMADA_READ_PARAM_OFFSET,
value);
writel(value, devbus->base + ARMADA_READ_PARAM_OFFSET);
/* Set write timings */
value = w->sync_enable << ARMADA_SYNC_ENABLE_SHIFT |
w->wr_low << ARMADA_WR_LOW_SHIFT |
w->wr_high << ARMADA_WR_HIGH_SHIFT |
w->ale_wr;
dev_dbg(devbus->dev, "write parameters register: 0x%p = 0x%x\n",
devbus->base + ARMADA_WRITE_PARAM_OFFSET,
value);
writel(value, devbus->base + ARMADA_WRITE_PARAM_OFFSET);
}
static int mvebu_devbus_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *node = pdev->dev.of_node;
struct devbus_read_params r;
struct devbus_write_params w;
struct devbus *devbus;
struct resource *res;
struct clk *clk;
unsigned long rate;
int err;
devbus = devm_kzalloc(&pdev->dev, sizeof(struct devbus), GFP_KERNEL);
if (!devbus)
return -ENOMEM;
devbus->dev = dev;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
devbus->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(devbus->base))
return PTR_ERR(devbus->base);
clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(clk))
return PTR_ERR(clk);
clk_prepare_enable(clk);
/*
* Obtain clock period in picoseconds,
* we need this in order to convert timing
* parameters from cycles to picoseconds.
*/
rate = clk_get_rate(clk) / 1000;
devbus->tick_ps = 1000000000 / rate;
dev_dbg(devbus->dev, "Setting timing parameter, tick is %lu ps\n",
devbus->tick_ps);
if (!of_property_read_bool(node, "devbus,keep-config")) {
/* Read the Device Tree node */
err = devbus_get_timing_params(devbus, node, &r, &w);
if (err < 0)
return err;
/* Set the new timing parameters */
if (of_device_is_compatible(node, "marvell,orion-devbus"))
devbus_orion_set_timing_params(devbus, node, &r, &w);
else
devbus_armada_set_timing_params(devbus, node, &r, &w);
}
/*
* We need to create a child device explicitly from here to
* guarantee that the child will be probed after the timing
* parameters for the bus are written.
*/
err = of_platform_populate(node, NULL, NULL, dev);
if (err < 0)
return err;
return 0;
}
static const struct of_device_id mvebu_devbus_of_match[] = {
{ .compatible = "marvell,mvebu-devbus" },
{ .compatible = "marvell,orion-devbus" },
{},
};
MODULE_DEVICE_TABLE(of, mvebu_devbus_of_match);
static struct platform_driver mvebu_devbus_driver = {
.probe = mvebu_devbus_probe,
.driver = {
.name = "mvebu-devbus",
.owner = THIS_MODULE,
.of_match_table = mvebu_devbus_of_match,
},
};
static int __init mvebu_devbus_init(void)
{
return platform_driver_register(&mvebu_devbus_driver);
}
module_init(mvebu_devbus_init);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Ezequiel Garcia <ezequiel.garcia@free-electrons.com>");
MODULE_DESCRIPTION("Marvell EBU SoC Device Bus controller");