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linux_dsm_epyc7002/drivers/mtd/nand/mtk_ecc.c
Arnd Bergmann 8ff0513bdc mtd: mtk: avoid warning in mtk_ecc_encode 
When building with -Wmaybe-uninitialized, gcc produces a silly false positive
warning for the mtk_ecc_encode function:

drivers/mtd/nand/mtk_ecc.c: In function 'mtk_ecc_encode':
drivers/mtd/nand/mtk_ecc.c:402:15: error: 'val' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The function for some reason contains a double byte swap on big-endian
builds to get the OOB data into the correct order again, and is written
in a slightly confusing way.

Using a simple memcpy32_fromio() to read the data simplifies it a lot
so it becomes more readable and produces no warning. However, the
output might not have 32-bit alignment, so we have to use another
memcpy to avoid taking alignment faults or writing beyond the end
of the array.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: RogerCC Lin <rogercc.lin@mediatek.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
2016-10-28 10:21:23 +02:00

534 lines
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/*
* MTK ECC controller driver.
* Copyright (C) 2016 MediaTek Inc.
* Authors: Xiaolei Li <xiaolei.li@mediatek.com>
* Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
*
* 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.
*
* 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.
*/
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/iopoll.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/mutex.h>
#include "mtk_ecc.h"
#define ECC_IDLE_MASK BIT(0)
#define ECC_IRQ_EN BIT(0)
#define ECC_OP_ENABLE (1)
#define ECC_OP_DISABLE (0)
#define ECC_ENCCON (0x00)
#define ECC_ENCCNFG (0x04)
#define ECC_CNFG_4BIT (0)
#define ECC_CNFG_6BIT (1)
#define ECC_CNFG_8BIT (2)
#define ECC_CNFG_10BIT (3)
#define ECC_CNFG_12BIT (4)
#define ECC_CNFG_14BIT (5)
#define ECC_CNFG_16BIT (6)
#define ECC_CNFG_18BIT (7)
#define ECC_CNFG_20BIT (8)
#define ECC_CNFG_22BIT (9)
#define ECC_CNFG_24BIT (0xa)
#define ECC_CNFG_28BIT (0xb)
#define ECC_CNFG_32BIT (0xc)
#define ECC_CNFG_36BIT (0xd)
#define ECC_CNFG_40BIT (0xe)
#define ECC_CNFG_44BIT (0xf)
#define ECC_CNFG_48BIT (0x10)
#define ECC_CNFG_52BIT (0x11)
#define ECC_CNFG_56BIT (0x12)
#define ECC_CNFG_60BIT (0x13)
#define ECC_MODE_SHIFT (5)
#define ECC_MS_SHIFT (16)
#define ECC_ENCDIADDR (0x08)
#define ECC_ENCIDLE (0x0C)
#define ECC_ENCPAR(x) (0x10 + (x) * sizeof(u32))
#define ECC_ENCIRQ_EN (0x80)
#define ECC_ENCIRQ_STA (0x84)
#define ECC_DECCON (0x100)
#define ECC_DECCNFG (0x104)
#define DEC_EMPTY_EN BIT(31)
#define DEC_CNFG_CORRECT (0x3 << 12)
#define ECC_DECIDLE (0x10C)
#define ECC_DECENUM0 (0x114)
#define ERR_MASK (0x3f)
#define ECC_DECDONE (0x124)
#define ECC_DECIRQ_EN (0x200)
#define ECC_DECIRQ_STA (0x204)
#define ECC_TIMEOUT (500000)
#define ECC_IDLE_REG(op) ((op) == ECC_ENCODE ? ECC_ENCIDLE : ECC_DECIDLE)
#define ECC_CTL_REG(op) ((op) == ECC_ENCODE ? ECC_ENCCON : ECC_DECCON)
#define ECC_IRQ_REG(op) ((op) == ECC_ENCODE ? \
ECC_ENCIRQ_EN : ECC_DECIRQ_EN)
struct mtk_ecc {
struct device *dev;
void __iomem *regs;
struct clk *clk;
struct completion done;
struct mutex lock;
u32 sectors;
u8 eccdata[112];
};
static inline void mtk_ecc_wait_idle(struct mtk_ecc *ecc,
enum mtk_ecc_operation op)
{
struct device *dev = ecc->dev;
u32 val;
int ret;
ret = readl_poll_timeout_atomic(ecc->regs + ECC_IDLE_REG(op), val,
val & ECC_IDLE_MASK,
10, ECC_TIMEOUT);
if (ret)
dev_warn(dev, "%s NOT idle\n",
op == ECC_ENCODE ? "encoder" : "decoder");
}
static irqreturn_t mtk_ecc_irq(int irq, void *id)
{
struct mtk_ecc *ecc = id;
enum mtk_ecc_operation op;
u32 dec, enc;
dec = readw(ecc->regs + ECC_DECIRQ_STA) & ECC_IRQ_EN;
if (dec) {
op = ECC_DECODE;
dec = readw(ecc->regs + ECC_DECDONE);
if (dec & ecc->sectors) {
ecc->sectors = 0;
complete(&ecc->done);
} else {
return IRQ_HANDLED;
}
} else {
enc = readl(ecc->regs + ECC_ENCIRQ_STA) & ECC_IRQ_EN;
if (enc) {
op = ECC_ENCODE;
complete(&ecc->done);
} else {
return IRQ_NONE;
}
}
writel(0, ecc->regs + ECC_IRQ_REG(op));
return IRQ_HANDLED;
}
static void mtk_ecc_config(struct mtk_ecc *ecc, struct mtk_ecc_config *config)
{
u32 ecc_bit = ECC_CNFG_4BIT, dec_sz, enc_sz;
u32 reg;
switch (config->strength) {
case 4:
ecc_bit = ECC_CNFG_4BIT;
break;
case 6:
ecc_bit = ECC_CNFG_6BIT;
break;
case 8:
ecc_bit = ECC_CNFG_8BIT;
break;
case 10:
ecc_bit = ECC_CNFG_10BIT;
break;
case 12:
ecc_bit = ECC_CNFG_12BIT;
break;
case 14:
ecc_bit = ECC_CNFG_14BIT;
break;
case 16:
ecc_bit = ECC_CNFG_16BIT;
break;
case 18:
ecc_bit = ECC_CNFG_18BIT;
break;
case 20:
ecc_bit = ECC_CNFG_20BIT;
break;
case 22:
ecc_bit = ECC_CNFG_22BIT;
break;
case 24:
ecc_bit = ECC_CNFG_24BIT;
break;
case 28:
ecc_bit = ECC_CNFG_28BIT;
break;
case 32:
ecc_bit = ECC_CNFG_32BIT;
break;
case 36:
ecc_bit = ECC_CNFG_36BIT;
break;
case 40:
ecc_bit = ECC_CNFG_40BIT;
break;
case 44:
ecc_bit = ECC_CNFG_44BIT;
break;
case 48:
ecc_bit = ECC_CNFG_48BIT;
break;
case 52:
ecc_bit = ECC_CNFG_52BIT;
break;
case 56:
ecc_bit = ECC_CNFG_56BIT;
break;
case 60:
ecc_bit = ECC_CNFG_60BIT;
break;
default:
dev_err(ecc->dev, "invalid strength %d, default to 4 bits\n",
config->strength);
}
if (config->op == ECC_ENCODE) {
/* configure ECC encoder (in bits) */
enc_sz = config->len << 3;
reg = ecc_bit | (config->mode << ECC_MODE_SHIFT);
reg |= (enc_sz << ECC_MS_SHIFT);
writel(reg, ecc->regs + ECC_ENCCNFG);
if (config->mode != ECC_NFI_MODE)
writel(lower_32_bits(config->addr),
ecc->regs + ECC_ENCDIADDR);
} else {
/* configure ECC decoder (in bits) */
dec_sz = (config->len << 3) +
config->strength * ECC_PARITY_BITS;
reg = ecc_bit | (config->mode << ECC_MODE_SHIFT);
reg |= (dec_sz << ECC_MS_SHIFT) | DEC_CNFG_CORRECT;
reg |= DEC_EMPTY_EN;
writel(reg, ecc->regs + ECC_DECCNFG);
if (config->sectors)
ecc->sectors = 1 << (config->sectors - 1);
}
}
void mtk_ecc_get_stats(struct mtk_ecc *ecc, struct mtk_ecc_stats *stats,
int sectors)
{
u32 offset, i, err;
u32 bitflips = 0;
stats->corrected = 0;
stats->failed = 0;
for (i = 0; i < sectors; i++) {
offset = (i >> 2) << 2;
err = readl(ecc->regs + ECC_DECENUM0 + offset);
err = err >> ((i % 4) * 8);
err &= ERR_MASK;
if (err == ERR_MASK) {
/* uncorrectable errors */
stats->failed++;
continue;
}
stats->corrected += err;
bitflips = max_t(u32, bitflips, err);
}
stats->bitflips = bitflips;
}
EXPORT_SYMBOL(mtk_ecc_get_stats);
void mtk_ecc_release(struct mtk_ecc *ecc)
{
clk_disable_unprepare(ecc->clk);
put_device(ecc->dev);
}
EXPORT_SYMBOL(mtk_ecc_release);
static void mtk_ecc_hw_init(struct mtk_ecc *ecc)
{
mtk_ecc_wait_idle(ecc, ECC_ENCODE);
writew(ECC_OP_DISABLE, ecc->regs + ECC_ENCCON);
mtk_ecc_wait_idle(ecc, ECC_DECODE);
writel(ECC_OP_DISABLE, ecc->regs + ECC_DECCON);
}
static struct mtk_ecc *mtk_ecc_get(struct device_node *np)
{
struct platform_device *pdev;
struct mtk_ecc *ecc;
pdev = of_find_device_by_node(np);
if (!pdev || !platform_get_drvdata(pdev))
return ERR_PTR(-EPROBE_DEFER);
get_device(&pdev->dev);
ecc = platform_get_drvdata(pdev);
clk_prepare_enable(ecc->clk);
mtk_ecc_hw_init(ecc);
return ecc;
}
struct mtk_ecc *of_mtk_ecc_get(struct device_node *of_node)
{
struct mtk_ecc *ecc = NULL;
struct device_node *np;
np = of_parse_phandle(of_node, "ecc-engine", 0);
if (np) {
ecc = mtk_ecc_get(np);
of_node_put(np);
}
return ecc;
}
EXPORT_SYMBOL(of_mtk_ecc_get);
int mtk_ecc_enable(struct mtk_ecc *ecc, struct mtk_ecc_config *config)
{
enum mtk_ecc_operation op = config->op;
int ret;
ret = mutex_lock_interruptible(&ecc->lock);
if (ret) {
dev_err(ecc->dev, "interrupted when attempting to lock\n");
return ret;
}
mtk_ecc_wait_idle(ecc, op);
mtk_ecc_config(ecc, config);
writew(ECC_OP_ENABLE, ecc->regs + ECC_CTL_REG(op));
init_completion(&ecc->done);
writew(ECC_IRQ_EN, ecc->regs + ECC_IRQ_REG(op));
return 0;
}
EXPORT_SYMBOL(mtk_ecc_enable);
void mtk_ecc_disable(struct mtk_ecc *ecc)
{
enum mtk_ecc_operation op = ECC_ENCODE;
/* find out the running operation */
if (readw(ecc->regs + ECC_CTL_REG(op)) != ECC_OP_ENABLE)
op = ECC_DECODE;
/* disable it */
mtk_ecc_wait_idle(ecc, op);
writew(0, ecc->regs + ECC_IRQ_REG(op));
writew(ECC_OP_DISABLE, ecc->regs + ECC_CTL_REG(op));
mutex_unlock(&ecc->lock);
}
EXPORT_SYMBOL(mtk_ecc_disable);
int mtk_ecc_wait_done(struct mtk_ecc *ecc, enum mtk_ecc_operation op)
{
int ret;
ret = wait_for_completion_timeout(&ecc->done, msecs_to_jiffies(500));
if (!ret) {
dev_err(ecc->dev, "%s timeout - interrupt did not arrive)\n",
(op == ECC_ENCODE) ? "encoder" : "decoder");
return -ETIMEDOUT;
}
return 0;
}
EXPORT_SYMBOL(mtk_ecc_wait_done);
int mtk_ecc_encode(struct mtk_ecc *ecc, struct mtk_ecc_config *config,
u8 *data, u32 bytes)
{
dma_addr_t addr;
u32 len;
int ret;
addr = dma_map_single(ecc->dev, data, bytes, DMA_TO_DEVICE);
ret = dma_mapping_error(ecc->dev, addr);
if (ret) {
dev_err(ecc->dev, "dma mapping error\n");
return -EINVAL;
}
config->op = ECC_ENCODE;
config->addr = addr;
ret = mtk_ecc_enable(ecc, config);
if (ret) {
dma_unmap_single(ecc->dev, addr, bytes, DMA_TO_DEVICE);
return ret;
}
ret = mtk_ecc_wait_done(ecc, ECC_ENCODE);
if (ret)
goto timeout;
mtk_ecc_wait_idle(ecc, ECC_ENCODE);
/* Program ECC bytes to OOB: per sector oob = FDM + ECC + SPARE */
len = (config->strength * ECC_PARITY_BITS + 7) >> 3;
/* write the parity bytes generated by the ECC back to temp buffer */
__ioread32_copy(ecc->eccdata, ecc->regs + ECC_ENCPAR(0), round_up(len, 4));
/* copy into possibly unaligned OOB region with actual length */
memcpy(data + bytes, ecc->eccdata, len);
timeout:
dma_unmap_single(ecc->dev, addr, bytes, DMA_TO_DEVICE);
mtk_ecc_disable(ecc);
return ret;
}
EXPORT_SYMBOL(mtk_ecc_encode);
void mtk_ecc_adjust_strength(u32 *p)
{
u32 ecc[] = {4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 32, 36,
40, 44, 48, 52, 56, 60};
int i;
for (i = 0; i < ARRAY_SIZE(ecc); i++) {
if (*p <= ecc[i]) {
if (!i)
*p = ecc[i];
else if (*p != ecc[i])
*p = ecc[i - 1];
return;
}
}
*p = ecc[ARRAY_SIZE(ecc) - 1];
}
EXPORT_SYMBOL(mtk_ecc_adjust_strength);
static int mtk_ecc_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct mtk_ecc *ecc;
struct resource *res;
int irq, ret;
ecc = devm_kzalloc(dev, sizeof(*ecc), GFP_KERNEL);
if (!ecc)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
ecc->regs = devm_ioremap_resource(dev, res);
if (IS_ERR(ecc->regs)) {
dev_err(dev, "failed to map regs: %ld\n", PTR_ERR(ecc->regs));
return PTR_ERR(ecc->regs);
}
ecc->clk = devm_clk_get(dev, NULL);
if (IS_ERR(ecc->clk)) {
dev_err(dev, "failed to get clock: %ld\n", PTR_ERR(ecc->clk));
return PTR_ERR(ecc->clk);
}
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(dev, "failed to get irq\n");
return -EINVAL;
}
ret = dma_set_mask(dev, DMA_BIT_MASK(32));
if (ret) {
dev_err(dev, "failed to set DMA mask\n");
return ret;
}
ret = devm_request_irq(dev, irq, mtk_ecc_irq, 0x0, "mtk-ecc", ecc);
if (ret) {
dev_err(dev, "failed to request irq\n");
return -EINVAL;
}
ecc->dev = dev;
mutex_init(&ecc->lock);
platform_set_drvdata(pdev, ecc);
dev_info(dev, "probed\n");
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int mtk_ecc_suspend(struct device *dev)
{
struct mtk_ecc *ecc = dev_get_drvdata(dev);
clk_disable_unprepare(ecc->clk);
return 0;
}
static int mtk_ecc_resume(struct device *dev)
{
struct mtk_ecc *ecc = dev_get_drvdata(dev);
int ret;
ret = clk_prepare_enable(ecc->clk);
if (ret) {
dev_err(dev, "failed to enable clk\n");
return ret;
}
mtk_ecc_hw_init(ecc);
return 0;
}
static SIMPLE_DEV_PM_OPS(mtk_ecc_pm_ops, mtk_ecc_suspend, mtk_ecc_resume);
#endif
static const struct of_device_id mtk_ecc_dt_match[] = {
{ .compatible = "mediatek,mt2701-ecc" },
{},
};
MODULE_DEVICE_TABLE(of, mtk_ecc_dt_match);
static struct platform_driver mtk_ecc_driver = {
.probe = mtk_ecc_probe,
.driver = {
.name = "mtk-ecc",
.of_match_table = of_match_ptr(mtk_ecc_dt_match),
#ifdef CONFIG_PM_SLEEP
.pm = &mtk_ecc_pm_ops,
#endif
},
};
module_platform_driver(mtk_ecc_driver);
MODULE_AUTHOR("Xiaolei Li <xiaolei.li@mediatek.com>");
MODULE_DESCRIPTION("MTK Nand ECC Driver");
MODULE_LICENSE("GPL");
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