/*
* Error Location Module
*
* Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* 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.
*
*/
#define DRIVER_NAME "omap-elm"
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/sched.h>
#include <linux/pm_runtime.h>
#include <linux/platform_data/elm.h>
#define ELM_SYSCONFIG 0x010
#define ELM_IRQSTATUS 0x018
#define ELM_IRQENABLE 0x01c
#define ELM_LOCATION_CONFIG 0x020
#define ELM_PAGE_CTRL 0x080
#define ELM_SYNDROME_FRAGMENT_0 0x400
#define ELM_SYNDROME_FRAGMENT_1 0x404
#define ELM_SYNDROME_FRAGMENT_2 0x408
#define ELM_SYNDROME_FRAGMENT_3 0x40c
#define ELM_SYNDROME_FRAGMENT_4 0x410
#define ELM_SYNDROME_FRAGMENT_5 0x414
#define ELM_SYNDROME_FRAGMENT_6 0x418
#define ELM_LOCATION_STATUS 0x800
#define ELM_ERROR_LOCATION_0 0x880
/* ELM Interrupt Status Register */
#define INTR_STATUS_PAGE_VALID BIT(8)
/* ELM Interrupt Enable Register */
#define INTR_EN_PAGE_MASK BIT(8)
/* ELM Location Configuration Register */
#define ECC_BCH_LEVEL_MASK 0x3
/* ELM syndrome */
#define ELM_SYNDROME_VALID BIT(16)
/* ELM_LOCATION_STATUS Register */
#define ECC_CORRECTABLE_MASK BIT(8)
#define ECC_NB_ERRORS_MASK 0x1f
/* ELM_ERROR_LOCATION_0-15 Registers */
#define ECC_ERROR_LOCATION_MASK 0x1fff
#define ELM_ECC_SIZE 0x7ff
#define SYNDROME_FRAGMENT_REG_SIZE 0x40
#define ERROR_LOCATION_SIZE 0x100
struct elm_registers {
u32 elm_irqenable;
u32 elm_sysconfig;
u32 elm_location_config;
u32 elm_page_ctrl;
u32 elm_syndrome_fragment_6[ERROR_VECTOR_MAX];
u32 elm_syndrome_fragment_5[ERROR_VECTOR_MAX];
u32 elm_syndrome_fragment_4[ERROR_VECTOR_MAX];
u32 elm_syndrome_fragment_3[ERROR_VECTOR_MAX];
u32 elm_syndrome_fragment_2[ERROR_VECTOR_MAX];
u32 elm_syndrome_fragment_1[ERROR_VECTOR_MAX];
u32 elm_syndrome_fragment_0[ERROR_VECTOR_MAX];
};
struct elm_info {
struct device *dev;
void __iomem *elm_base;
struct completion elm_completion;
struct list_head list;
enum bch_ecc bch_type;
struct elm_registers elm_regs;
int ecc_steps;
int ecc_syndrome_size;
};
static LIST_HEAD(elm_devices);
static void elm_write_reg(struct elm_info *info, int offset, u32 val)
{
writel(val, info->elm_base + offset);
}
static u32 elm_read_reg(struct elm_info *info, int offset)
{
return readl(info->elm_base + offset);
}
/**
* elm_config - Configure ELM module
* @dev: ELM device
* @bch_type: Type of BCH ecc
*/
int elm_config(struct device *dev, enum bch_ecc bch_type,
int ecc_steps, int ecc_step_size, int ecc_syndrome_size)
{
u32 reg_val;
struct elm_info *info = dev_get_drvdata(dev);
if (!info) {
dev_err(dev, "Unable to configure elm - device not probed?\n");
return -EPROBE_DEFER;
}
/* ELM cannot detect ECC errors for chunks > 1KB */
if (ecc_step_size > ((ELM_ECC_SIZE + 1) / 2)) {
dev_err(dev, "unsupported config ecc-size=%d\n", ecc_step_size);
return -EINVAL;
}
/* ELM support 8 error syndrome process */
if (ecc_steps > ERROR_VECTOR_MAX) {
dev_err(dev, "unsupported config ecc-step=%d\n", ecc_steps);
return -EINVAL;
}
reg_val = (bch_type & ECC_BCH_LEVEL_MASK) | (ELM_ECC_SIZE << 16);
elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val);
info->bch_type = bch_type;
info->ecc_steps = ecc_steps;
info->ecc_syndrome_size = ecc_syndrome_size;
return 0;
}
EXPORT_SYMBOL(elm_config);
/**
* elm_configure_page_mode - Enable/Disable page mode
* @info: elm info
* @index: index number of syndrome fragment vector
* @enable: enable/disable flag for page mode
*
* Enable page mode for syndrome fragment index
*/
static void elm_configure_page_mode(struct elm_info *info, int index,
bool enable)
{
u32 reg_val;
reg_val = elm_read_reg(info, ELM_PAGE_CTRL);
if (enable)
reg_val |= BIT(index); /* enable page mode */
else
reg_val &= ~BIT(index); /* disable page mode */
elm_write_reg(info, ELM_PAGE_CTRL, reg_val);
}
/**
* elm_load_syndrome - Load ELM syndrome reg
* @info: elm info
* @err_vec: elm error vectors
* @ecc: buffer with calculated ecc
*
* Load syndrome fragment registers with calculated ecc in reverse order.
*/
static void elm_load_syndrome(struct elm_info *info,
struct elm_errorvec *err_vec, u8 *ecc)
{
int i, offset;
u32 val;
for (i = 0; i < info->ecc_steps; i++) {
/* Check error reported */
if (err_vec[i].error_reported) {
elm_configure_page_mode(info, i, true);
offset = ELM_SYNDROME_FRAGMENT_0 +
SYNDROME_FRAGMENT_REG_SIZE * i;
switch (info->bch_type) {
case BCH8_ECC:
/* syndrome fragment 0 = ecc[9-12B] */
val = cpu_to_be32(*(u32 *) &ecc[9]);
elm_write_reg(info, offset, val);
/* syndrome fragment 1 = ecc[5-8B] */
offset += 4;
val = cpu_to_be32(*(u32 *) &ecc[5]);
elm_write_reg(info, offset, val);
/* syndrome fragment 2 = ecc[1-4B] */
offset += 4;
val = cpu_to_be32(*(u32 *) &ecc[1]);
elm_write_reg(info, offset, val);
/* syndrome fragment 3 = ecc[0B] */
offset += 4;
val = ecc[0];
elm_write_reg(info, offset, val);
break;
case BCH4_ECC:
/* syndrome fragment 0 = ecc[20-52b] bits */
val = (cpu_to_be32(*(u32 *) &ecc[3]) >> 4) |
((ecc[2] & 0xf) << 28);
elm_write_reg(info, offset, val);
/* syndrome fragment 1 = ecc[0-20b] bits */
offset += 4;
val = cpu_to_be32(*(u32 *) &ecc[0]) >> 12;
elm_write_reg(info, offset, val);
break;
case BCH16_ECC:
val = cpu_to_be32(*(u32 *) &ecc[22]);
elm_write_reg(info, offset, val);
offset += 4;
val = cpu_to_be32(*(u32 *) &ecc[18]);
elm_write_reg(info, offset, val);
offset += 4;
val = cpu_to_be32(*(u32 *) &ecc[14]);
elm_write_reg(info, offset, val);
offset += 4;
val = cpu_to_be32(*(u32 *) &ecc[10]);
elm_write_reg(info, offset, val);
offset += 4;
val = cpu_to_be32(*(u32 *) &ecc[6]);
elm_write_reg(info, offset, val);
offset += 4;
val = cpu_to_be32(*(u32 *) &ecc[2]);
elm_write_reg(info, offset, val);
offset += 4;
val = cpu_to_be32(*(u32 *) &ecc[0]) >> 16;
elm_write_reg(info, offset, val);
break;
default:
pr_err("invalid config bch_type\n");
}
}
/* Update ecc pointer with ecc byte size */
ecc += info->ecc_syndrome_size;
}
}
/**
* elm_start_processing - start elm syndrome processing
* @info: elm info
* @err_vec: elm error vectors
*
* Set syndrome valid bit for syndrome fragment registers for which
* elm syndrome fragment registers are loaded. This enables elm module
* to start processing syndrome vectors.
*/
static void elm_start_processing(struct elm_info *info,
struct elm_errorvec *err_vec)
{
int i, offset;
u32 reg_val;
/*
* Set syndrome vector valid, so that ELM module
* will process it for vectors error is reported
*/
for (i = 0; i < info->ecc_steps; i++) {
if (err_vec[i].error_reported) {
offset = ELM_SYNDROME_FRAGMENT_6 +
SYNDROME_FRAGMENT_REG_SIZE * i;
reg_val = elm_read_reg(info, offset);
reg_val |= ELM_SYNDROME_VALID;
elm_write_reg(info, offset, reg_val);
}
}
}
/**
* elm_error_correction - locate correctable error position
* @info: elm info
* @err_vec: elm error vectors
*
* On completion of processing by elm module, error location status
* register updated with correctable/uncorrectable error information.
* In case of correctable errors, number of errors located from
* elm location status register & read the positions from
* elm error location register.
*/
static void elm_error_correction(struct elm_