430 lines
9.6 KiB
C
430 lines
9.6 KiB
C
/*
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* sst25l.c
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*
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* Driver for SST25L SPI Flash chips
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*
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* Copyright © 2009 Bluewater Systems Ltd
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* Author: Andre Renaud <andre@bluewatersys.com>
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* Author: Ryan Mallon
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*
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* Based on m25p80.c
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*
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* This code is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/mutex.h>
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#include <linux/interrupt.h>
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <linux/mtd/mtd.h>
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#include <linux/mtd/partitions.h>
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#include <linux/spi/spi.h>
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#include <linux/spi/flash.h>
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/* Erases can take up to 3 seconds! */
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#define MAX_READY_WAIT_JIFFIES msecs_to_jiffies(3000)
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#define SST25L_CMD_WRSR 0x01 /* Write status register */
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#define SST25L_CMD_WRDI 0x04 /* Write disable */
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#define SST25L_CMD_RDSR 0x05 /* Read status register */
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#define SST25L_CMD_WREN 0x06 /* Write enable */
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#define SST25L_CMD_READ 0x03 /* High speed read */
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#define SST25L_CMD_EWSR 0x50 /* Enable write status register */
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#define SST25L_CMD_SECTOR_ERASE 0x20 /* Erase sector */
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#define SST25L_CMD_READ_ID 0x90 /* Read device ID */
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#define SST25L_CMD_AAI_PROGRAM 0xaf /* Auto address increment */
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#define SST25L_STATUS_BUSY (1 << 0) /* Chip is busy */
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#define SST25L_STATUS_WREN (1 << 1) /* Write enabled */
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#define SST25L_STATUS_BP0 (1 << 2) /* Block protection 0 */
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#define SST25L_STATUS_BP1 (1 << 3) /* Block protection 1 */
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struct sst25l_flash {
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struct spi_device *spi;
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struct mutex lock;
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struct mtd_info mtd;
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};
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struct flash_info {
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const char *name;
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uint16_t device_id;
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unsigned page_size;
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unsigned nr_pages;
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unsigned erase_size;
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};
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#define to_sst25l_flash(x) container_of(x, struct sst25l_flash, mtd)
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static struct flash_info sst25l_flash_info[] = {
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{"sst25lf020a", 0xbf43, 256, 1024, 4096},
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{"sst25lf040a", 0xbf44, 256, 2048, 4096},
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};
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static int sst25l_status(struct sst25l_flash *flash, int *status)
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{
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struct spi_message m;
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struct spi_transfer t;
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unsigned char cmd_resp[2];
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int err;
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spi_message_init(&m);
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memset(&t, 0, sizeof(struct spi_transfer));
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cmd_resp[0] = SST25L_CMD_RDSR;
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cmd_resp[1] = 0xff;
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t.tx_buf = cmd_resp;
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t.rx_buf = cmd_resp;
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t.len = sizeof(cmd_resp);
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spi_message_add_tail(&t, &m);
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err = spi_sync(flash->spi, &m);
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if (err < 0)
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return err;
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*status = cmd_resp[1];
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return 0;
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}
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static int sst25l_write_enable(struct sst25l_flash *flash, int enable)
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{
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unsigned char command[2];
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int status, err;
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command[0] = enable ? SST25L_CMD_WREN : SST25L_CMD_WRDI;
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err = spi_write(flash->spi, command, 1);
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if (err)
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return err;
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command[0] = SST25L_CMD_EWSR;
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err = spi_write(flash->spi, command, 1);
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if (err)
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return err;
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command[0] = SST25L_CMD_WRSR;
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command[1] = enable ? 0 : SST25L_STATUS_BP0 | SST25L_STATUS_BP1;
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err = spi_write(flash->spi, command, 2);
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if (err)
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return err;
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if (enable) {
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err = sst25l_status(flash, &status);
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if (err)
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return err;
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if (!(status & SST25L_STATUS_WREN))
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return -EROFS;
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}
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return 0;
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}
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static int sst25l_wait_till_ready(struct sst25l_flash *flash)
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{
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unsigned long deadline;
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int status, err;
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deadline = jiffies + MAX_READY_WAIT_JIFFIES;
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do {
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err = sst25l_status(flash, &status);
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if (err)
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return err;
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if (!(status & SST25L_STATUS_BUSY))
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return 0;
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cond_resched();
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} while (!time_after_eq(jiffies, deadline));
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return -ETIMEDOUT;
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}
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static int sst25l_erase_sector(struct sst25l_flash *flash, uint32_t offset)
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{
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unsigned char command[4];
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int err;
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err = sst25l_write_enable(flash, 1);
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if (err)
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return err;
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command[0] = SST25L_CMD_SECTOR_ERASE;
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command[1] = offset >> 16;
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command[2] = offset >> 8;
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command[3] = offset;
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err = spi_write(flash->spi, command, 4);
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if (err)
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return err;
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err = sst25l_wait_till_ready(flash);
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if (err)
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return err;
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return sst25l_write_enable(flash, 0);
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}
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static int sst25l_erase(struct mtd_info *mtd, struct erase_info *instr)
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{
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struct sst25l_flash *flash = to_sst25l_flash(mtd);
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uint32_t addr, end;
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int err;
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/* Sanity checks */
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if ((uint32_t)instr->len % mtd->erasesize)
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return -EINVAL;
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if ((uint32_t)instr->addr % mtd->erasesize)
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return -EINVAL;
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addr = instr->addr;
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end = addr + instr->len;
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mutex_lock(&flash->lock);
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err = sst25l_wait_till_ready(flash);
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if (err) {
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mutex_unlock(&flash->lock);
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return err;
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}
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while (addr < end) {
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err = sst25l_erase_sector(flash, addr);
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if (err) {
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mutex_unlock(&flash->lock);
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instr->state = MTD_ERASE_FAILED;
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dev_err(&flash->spi->dev, "Erase failed\n");
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return err;
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}
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addr += mtd->erasesize;
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}
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mutex_unlock(&flash->lock);
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instr->state = MTD_ERASE_DONE;
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mtd_erase_callback(instr);
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return 0;
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}
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static int sst25l_read(struct mtd_info *mtd, loff_t from, size_t len,
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size_t *retlen, unsigned char *buf)
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{
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struct sst25l_flash *flash = to_sst25l_flash(mtd);
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struct spi_transfer transfer[2];
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struct spi_message message;
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unsigned char command[4];
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int ret;
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spi_message_init(&message);
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memset(&transfer, 0, sizeof(transfer));
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command[0] = SST25L_CMD_READ;
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command[1] = from >> 16;
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command[2] = from >> 8;
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command[3] = from;
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transfer[0].tx_buf = command;
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transfer[0].len = sizeof(command);
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spi_message_add_tail(&transfer[0], &message);
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transfer[1].rx_buf = buf;
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transfer[1].len = len;
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spi_message_add_tail(&transfer[1], &message);
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mutex_lock(&flash->lock);
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/* Wait for previous write/erase to complete */
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ret = sst25l_wait_till_ready(flash);
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if (ret) {
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mutex_unlock(&flash->lock);
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return ret;
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}
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spi_sync(flash->spi, &message);
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if (retlen && message.actual_length > sizeof(command))
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*retlen += message.actual_length - sizeof(command);
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mutex_unlock(&flash->lock);
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return 0;
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}
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static int sst25l_write(struct mtd_info *mtd, loff_t to, size_t len,
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size_t *retlen, const unsigned char *buf)
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{
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struct sst25l_flash *flash = to_sst25l_flash(mtd);
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int i, j, ret, bytes, copied = 0;
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unsigned char command[5];
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if ((uint32_t)to % mtd->writesize)
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return -EINVAL;
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mutex_lock(&flash->lock);
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ret = sst25l_write_enable(flash, 1);
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if (ret)
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goto out;
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for (i = 0; i < len; i += mtd->writesize) {
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ret = sst25l_wait_till_ready(flash);
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if (ret)
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goto out;
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/* Write the first byte of the page */
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command[0] = SST25L_CMD_AAI_PROGRAM;
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command[1] = (to + i) >> 16;
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command[2] = (to + i) >> 8;
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command[3] = (to + i);
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command[4] = buf[i];
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ret = spi_write(flash->spi, command, 5);
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if (ret < 0)
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goto out;
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copied++;
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/*
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* Write the remaining bytes using auto address
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* increment mode
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*/
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bytes = min_t(uint32_t, mtd->writesize, len - i);
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for (j = 1; j < bytes; j++, copied++) {
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ret = sst25l_wait_till_ready(flash);
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if (ret)
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goto out;
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command[1] = buf[i + j];
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ret = spi_write(flash->spi, command, 2);
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if (ret)
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goto out;
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}
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}
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out:
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ret = sst25l_write_enable(flash, 0);
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if (retlen)
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*retlen = copied;
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mutex_unlock(&flash->lock);
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return ret;
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}
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static struct flash_info *sst25l_match_device(struct spi_device *spi)
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{
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struct flash_info *flash_info = NULL;
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struct spi_message m;
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struct spi_transfer t;
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unsigned char cmd_resp[6];
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int i, err;
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uint16_t id;
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spi_message_init(&m);
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memset(&t, 0, sizeof(struct spi_transfer));
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cmd_resp[0] = SST25L_CMD_READ_ID;
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cmd_resp[1] = 0;
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cmd_resp[2] = 0;
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cmd_resp[3] = 0;
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cmd_resp[4] = 0xff;
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cmd_resp[5] = 0xff;
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t.tx_buf = cmd_resp;
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t.rx_buf = cmd_resp;
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t.len = sizeof(cmd_resp);
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spi_message_add_tail(&t, &m);
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err = spi_sync(spi, &m);
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if (err < 0) {
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dev_err(&spi->dev, "error reading device id\n");
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return NULL;
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}
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id = (cmd_resp[4] << 8) | cmd_resp[5];
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for (i = 0; i < ARRAY_SIZE(sst25l_flash_info); i++)
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if (sst25l_flash_info[i].device_id == id)
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flash_info = &sst25l_flash_info[i];
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if (!flash_info)
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dev_err(&spi->dev, "unknown id %.4x\n", id);
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return flash_info;
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}
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static int sst25l_probe(struct spi_device *spi)
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{
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struct flash_info *flash_info;
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struct sst25l_flash *flash;
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struct flash_platform_data *data;
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int ret;
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flash_info = sst25l_match_device(spi);
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if (!flash_info)
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return -ENODEV;
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flash = devm_kzalloc(&spi->dev, sizeof(*flash), GFP_KERNEL);
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if (!flash)
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return -ENOMEM;
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flash->spi = spi;
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mutex_init(&flash->lock);
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spi_set_drvdata(spi, flash);
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data = dev_get_platdata(&spi->dev);
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if (data && data->name)
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flash->mtd.name = data->name;
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flash->mtd.dev.parent = &spi->dev;
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flash->mtd.type = MTD_NORFLASH;
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flash->mtd.flags = MTD_CAP_NORFLASH;
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flash->mtd.erasesize = flash_info->erase_size;
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flash->mtd.writesize = flash_info->page_size;
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flash->mtd.writebufsize = flash_info->page_size;
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flash->mtd.size = flash_info->page_size * flash_info->nr_pages;
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flash->mtd._erase = sst25l_erase;
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flash->mtd._read = sst25l_read;
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flash->mtd._write = sst25l_write;
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dev_info(&spi->dev, "%s (%lld KiB)\n", flash_info->name,
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(long long)flash->mtd.size >> 10);
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pr_debug("mtd .name = %s, .size = 0x%llx (%lldMiB) "
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".erasesize = 0x%.8x (%uKiB) .numeraseregions = %d\n",
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flash->mtd.name,
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(long long)flash->mtd.size, (long long)(flash->mtd.size >> 20),
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flash->mtd.erasesize, flash->mtd.erasesize / 1024,
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flash->mtd.numeraseregions);
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ret = mtd_device_parse_register(&flash->mtd, NULL, NULL,
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data ? data->parts : NULL,
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data ? data->nr_parts : 0);
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if (ret)
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return -ENODEV;
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return 0;
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}
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static int sst25l_remove(struct spi_device *spi)
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{
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struct sst25l_flash *flash = spi_get_drvdata(spi);
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return mtd_device_unregister(&flash->mtd);
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}
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static struct spi_driver sst25l_driver = {
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.driver = {
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.name = "sst25l",
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},
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.probe = sst25l_probe,
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.remove = sst25l_remove,
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};
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module_spi_driver(sst25l_driver);
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MODULE_DESCRIPTION("MTD SPI driver for SST25L Flash chips");
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MODULE_AUTHOR("Andre Renaud <andre@bluewatersys.com>, "
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"Ryan Mallon");
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MODULE_LICENSE("GPL");
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