linux/drivers/mtd/nand/raw/denali_dt.c
Masahiro Yamada 711fafc287 mtd: rawnand: denali_dt: add reset controlling
According to the Denali NAND Flash Memory Controller User's Guide,
this IP has two reset signals.

  rst_n:     reset most of FFs in the controller core
  reg_rst_n: reset all FFs in the register interface, and in the
             initialization sequencer

This commit supports controlling those reset signals.

It is possible to control them separately from the IP point of view
although they might be often tied up together in actual SoC integration.

The IP spec says, asserting only the reg_rst_n without asserting rst_n
will cause unpredictable behavior in the controller. So, the driver
deasserts ->rst_reg and ->rst in this order.

Another thing that should be kept in mind is the automated initialization
sequence (a.k.a. 'bootstrap' process) is kicked off when reg_rst_n is
deasserted.

When the reset is deasserted, the controller issues a RESET command
to the chip select 0, and attempts to read out the chip ID, and further
more, ONFI parameters if it is an ONFI-compliant device. Then, the
controller sets up the relevant registers based on the detected
device parameters.

This process might be useful for tiny boot firmware, but is redundant
for Linux Kernel because nand_scan_ident() probes devices and sets up
parameters accordingly. Rather, this hardware feature is annoying
because it ends up with misdetection due to bugs.

So, commit 0615e7ad5d ("mtd: nand: denali: remove Toshiba and Hynix
specific fixup code") changed the driver to not rely on it.

However, there is no way to prevent it from running. The IP provides
the 'bootstrap_inhibit_init' port to suppress this sequence, but it is
usually out of software control, and dependent on SoC implementation.
As for the Socionext UniPhier platform, LD4 always enables it. For the
later SoCs, the bootstrap sequence runs depending on the boot mode.

I added usleep_range() to make the driver wait until the sequence
finishes. Otherwise, the driver would fail to detect the chip due
to the race between the driver and hardware-controlled sequence.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
2020-01-21 20:00:33 +01:00

266 lines
6.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* NAND Flash Controller Device Driver for DT
*
* Copyright © 2011, Picochip.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/reset.h>
#include "denali.h"
struct denali_dt {
struct denali_controller controller;
struct clk *clk; /* core clock */
struct clk *clk_x; /* bus interface clock */
struct clk *clk_ecc; /* ECC circuit clock */
struct reset_control *rst; /* core reset */
struct reset_control *rst_reg; /* register reset */
};
struct denali_dt_data {
unsigned int revision;
unsigned int caps;
unsigned int oob_skip_bytes;
const struct nand_ecc_caps *ecc_caps;
};
NAND_ECC_CAPS_SINGLE(denali_socfpga_ecc_caps, denali_calc_ecc_bytes,
512, 8, 15);
static const struct denali_dt_data denali_socfpga_data = {
.caps = DENALI_CAP_HW_ECC_FIXUP,
.oob_skip_bytes = 2,
.ecc_caps = &denali_socfpga_ecc_caps,
};
NAND_ECC_CAPS_SINGLE(denali_uniphier_v5a_ecc_caps, denali_calc_ecc_bytes,
1024, 8, 16, 24);
static const struct denali_dt_data denali_uniphier_v5a_data = {
.caps = DENALI_CAP_HW_ECC_FIXUP |
DENALI_CAP_DMA_64BIT,
.oob_skip_bytes = 8,
.ecc_caps = &denali_uniphier_v5a_ecc_caps,
};
NAND_ECC_CAPS_SINGLE(denali_uniphier_v5b_ecc_caps, denali_calc_ecc_bytes,
1024, 8, 16);
static const struct denali_dt_data denali_uniphier_v5b_data = {
.revision = 0x0501,
.caps = DENALI_CAP_HW_ECC_FIXUP |
DENALI_CAP_DMA_64BIT,
.oob_skip_bytes = 8,
.ecc_caps = &denali_uniphier_v5b_ecc_caps,
};
static const struct of_device_id denali_nand_dt_ids[] = {
{
.compatible = "altr,socfpga-denali-nand",
.data = &denali_socfpga_data,
},
{
.compatible = "socionext,uniphier-denali-nand-v5a",
.data = &denali_uniphier_v5a_data,
},
{
.compatible = "socionext,uniphier-denali-nand-v5b",
.data = &denali_uniphier_v5b_data,
},
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, denali_nand_dt_ids);
static int denali_dt_chip_init(struct denali_controller *denali,
struct device_node *chip_np)
{
struct denali_chip *dchip;
u32 bank;
int nsels, i, ret;
nsels = of_property_count_u32_elems(chip_np, "reg");
if (nsels < 0)
return nsels;
dchip = devm_kzalloc(denali->dev, struct_size(dchip, sels, nsels),
GFP_KERNEL);
if (!dchip)
return -ENOMEM;
dchip->nsels = nsels;
for (i = 0; i < nsels; i++) {
ret = of_property_read_u32_index(chip_np, "reg", i, &bank);
if (ret)
return ret;
dchip->sels[i].bank = bank;
nand_set_flash_node(&dchip->chip, chip_np);
}
return denali_chip_init(denali, dchip);
}
static int denali_dt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct resource *res;
struct denali_dt *dt;
const struct denali_dt_data *data;
struct denali_controller *denali;
struct device_node *np;
int ret;
dt = devm_kzalloc(dev, sizeof(*dt), GFP_KERNEL);
if (!dt)
return -ENOMEM;
denali = &dt->controller;
data = of_device_get_match_data(dev);
if (WARN_ON(!data))
return -EINVAL;
denali->revision = data->revision;
denali->caps = data->caps;
denali->oob_skip_bytes = data->oob_skip_bytes;
denali->ecc_caps = data->ecc_caps;
denali->dev = dev;
denali->irq = platform_get_irq(pdev, 0);
if (denali->irq < 0)
return denali->irq;
res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "denali_reg");
denali->reg = devm_ioremap_resource(dev, res);
if (IS_ERR(denali->reg))
return PTR_ERR(denali->reg);
res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "nand_data");
denali->host = devm_ioremap_resource(dev, res);
if (IS_ERR(denali->host))
return PTR_ERR(denali->host);
dt->clk = devm_clk_get(dev, "nand");
if (IS_ERR(dt->clk))
return PTR_ERR(dt->clk);
dt->clk_x = devm_clk_get(dev, "nand_x");
if (IS_ERR(dt->clk_x))
return PTR_ERR(dt->clk_x);
dt->clk_ecc = devm_clk_get(dev, "ecc");
if (IS_ERR(dt->clk_ecc))
return PTR_ERR(dt->clk_ecc);
dt->rst = devm_reset_control_get_optional_shared(dev, "nand");
if (IS_ERR(dt->rst))
return PTR_ERR(dt->rst);
dt->rst_reg = devm_reset_control_get_optional_shared(dev, "reg");
if (IS_ERR(dt->rst_reg))
return PTR_ERR(dt->rst_reg);
ret = clk_prepare_enable(dt->clk);
if (ret)
return ret;
ret = clk_prepare_enable(dt->clk_x);
if (ret)
goto out_disable_clk;
ret = clk_prepare_enable(dt->clk_ecc);
if (ret)
goto out_disable_clk_x;
denali->clk_rate = clk_get_rate(dt->clk);
denali->clk_x_rate = clk_get_rate(dt->clk_x);
/*
* Deassert the register reset, and the core reset in this order.
* Deasserting the core reset while the register reset is asserted
* will cause unpredictable behavior in the controller.
*/
ret = reset_control_deassert(dt->rst_reg);
if (ret)
goto out_disable_clk_ecc;
ret = reset_control_deassert(dt->rst);
if (ret)
goto out_assert_rst_reg;
/*
* When the reset is deasserted, the initialization sequence is kicked
* (bootstrap process). The driver must wait until it finished.
* Otherwise, it will result in unpredictable behavior.
*/
usleep_range(200, 1000);
ret = denali_init(denali);
if (ret)
goto out_assert_rst;
for_each_child_of_node(dev->of_node, np) {
ret = denali_dt_chip_init(denali, np);
if (ret) {
of_node_put(np);
goto out_remove_denali;
}
}
platform_set_drvdata(pdev, dt);
return 0;
out_remove_denali:
denali_remove(denali);
out_assert_rst:
reset_control_assert(dt->rst);
out_assert_rst_reg:
reset_control_assert(dt->rst_reg);
out_disable_clk_ecc:
clk_disable_unprepare(dt->clk_ecc);
out_disable_clk_x:
clk_disable_unprepare(dt->clk_x);
out_disable_clk:
clk_disable_unprepare(dt->clk);
return ret;
}
static int denali_dt_remove(struct platform_device *pdev)
{
struct denali_dt *dt = platform_get_drvdata(pdev);
denali_remove(&dt->controller);
reset_control_assert(dt->rst);
reset_control_assert(dt->rst_reg);
clk_disable_unprepare(dt->clk_ecc);
clk_disable_unprepare(dt->clk_x);
clk_disable_unprepare(dt->clk);
return 0;
}
static struct platform_driver denali_dt_driver = {
.probe = denali_dt_probe,
.remove = denali_dt_remove,
.driver = {
.name = "denali-nand-dt",
.of_match_table = denali_nand_dt_ids,
},
};
module_platform_driver(denali_dt_driver);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Jamie Iles");
MODULE_DESCRIPTION("DT driver for Denali NAND controller");