385 lines
8.7 KiB
C
385 lines
8.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Driver for Microchip 48L640 64 Kb SPI Serial EERAM
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*
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* Copyright Heiko Schocher <hs@denx.de>
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*
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* datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/20006055B.pdf
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*
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* we set continuous mode but reading/writing more bytes than
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* pagesize seems to bring chip into state where readden values
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* are wrong ... no idea why.
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*
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*/
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/jiffies.h>
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#include <linux/module.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/mutex.h>
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#include <linux/sched.h>
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#include <linux/sizes.h>
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#include <linux/spi/flash.h>
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#include <linux/spi/spi.h>
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#include <linux/of_device.h>
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struct mchp48_caps {
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unsigned int size;
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unsigned int page_size;
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};
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struct mchp48l640_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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const struct mchp48_caps *caps;
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};
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#define MCHP48L640_CMD_WREN 0x06
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#define MCHP48L640_CMD_WRDI 0x04
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#define MCHP48L640_CMD_WRITE 0x02
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#define MCHP48L640_CMD_READ 0x03
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#define MCHP48L640_CMD_WRSR 0x01
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#define MCHP48L640_CMD_RDSR 0x05
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#define MCHP48L640_STATUS_RDY 0x01
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#define MCHP48L640_STATUS_WEL 0x02
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#define MCHP48L640_STATUS_BP0 0x04
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#define MCHP48L640_STATUS_BP1 0x08
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#define MCHP48L640_STATUS_SWM 0x10
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#define MCHP48L640_STATUS_PRO 0x20
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#define MCHP48L640_STATUS_ASE 0x40
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#define MCHP48L640_TIMEOUT 100
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#define MAX_CMD_SIZE 0x10
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#define to_mchp48l640_flash(x) container_of(x, struct mchp48l640_flash, mtd)
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static int mchp48l640_mkcmd(struct mchp48l640_flash *flash, u8 cmd, loff_t addr, char *buf)
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{
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buf[0] = cmd;
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buf[1] = addr >> 8;
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buf[2] = addr;
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return 3;
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}
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static int mchp48l640_read_status(struct mchp48l640_flash *flash, int *status)
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{
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unsigned char cmd[2];
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int ret;
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cmd[0] = MCHP48L640_CMD_RDSR;
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cmd[1] = 0x00;
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mutex_lock(&flash->lock);
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ret = spi_write_then_read(flash->spi, &cmd[0], 1, &cmd[1], 1);
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mutex_unlock(&flash->lock);
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if (!ret)
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*status = cmd[1];
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dev_dbg(&flash->spi->dev, "read status ret: %d status: %x", ret, *status);
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return ret;
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}
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static int mchp48l640_waitforbit(struct mchp48l640_flash *flash, int bit, bool set)
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{
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int ret, status;
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unsigned long deadline;
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deadline = jiffies + msecs_to_jiffies(MCHP48L640_TIMEOUT);
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do {
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ret = mchp48l640_read_status(flash, &status);
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dev_dbg(&flash->spi->dev, "read status ret: %d bit: %x %sset status: %x",
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ret, bit, (set ? "" : "not"), status);
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if (ret)
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return ret;
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if (set) {
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if ((status & bit) == bit)
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return 0;
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} else {
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if ((status & bit) == 0)
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return 0;
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}
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usleep_range(1000, 2000);
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} while (!time_after_eq(jiffies, deadline));
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dev_err(&flash->spi->dev, "Timeout waiting for bit %x %s set in status register.",
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bit, (set ? "" : "not"));
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return -ETIMEDOUT;
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}
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static int mchp48l640_write_prepare(struct mchp48l640_flash *flash, bool enable)
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{
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unsigned char cmd[2];
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int ret;
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if (enable)
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cmd[0] = MCHP48L640_CMD_WREN;
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else
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cmd[0] = MCHP48L640_CMD_WRDI;
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mutex_lock(&flash->lock);
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ret = spi_write(flash->spi, cmd, 1);
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mutex_unlock(&flash->lock);
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if (ret)
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dev_err(&flash->spi->dev, "write %sable failed ret: %d",
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(enable ? "en" : "dis"), ret);
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dev_dbg(&flash->spi->dev, "write %sable success ret: %d",
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(enable ? "en" : "dis"), ret);
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if (enable)
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return mchp48l640_waitforbit(flash, MCHP48L640_STATUS_WEL, true);
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return ret;
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}
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static int mchp48l640_set_mode(struct mchp48l640_flash *flash)
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{
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unsigned char cmd[2];
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int ret;
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ret = mchp48l640_write_prepare(flash, true);
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if (ret)
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return ret;
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cmd[0] = MCHP48L640_CMD_WRSR;
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cmd[1] = MCHP48L640_STATUS_PRO;
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mutex_lock(&flash->lock);
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ret = spi_write(flash->spi, cmd, 2);
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mutex_unlock(&flash->lock);
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if (ret)
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dev_err(&flash->spi->dev, "Could not set continuous mode ret: %d", ret);
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return mchp48l640_waitforbit(flash, MCHP48L640_STATUS_PRO, true);
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}
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static int mchp48l640_wait_rdy(struct mchp48l640_flash *flash)
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{
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return mchp48l640_waitforbit(flash, MCHP48L640_STATUS_RDY, false);
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};
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static int mchp48l640_write_page(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 mchp48l640_flash *flash = to_mchp48l640_flash(mtd);
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unsigned char *cmd;
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int ret;
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int cmdlen;
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cmd = kmalloc((3 + len), GFP_KERNEL | GFP_DMA);
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if (!cmd)
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return -ENOMEM;
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ret = mchp48l640_wait_rdy(flash);
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if (ret)
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goto fail;
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ret = mchp48l640_write_prepare(flash, true);
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if (ret)
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goto fail;
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mutex_lock(&flash->lock);
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cmdlen = mchp48l640_mkcmd(flash, MCHP48L640_CMD_WRITE, to, cmd);
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memcpy(&cmd[cmdlen], buf, len);
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ret = spi_write(flash->spi, cmd, cmdlen + len);
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mutex_unlock(&flash->lock);
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if (!ret)
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*retlen += len;
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else
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goto fail;
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ret = mchp48l640_waitforbit(flash, MCHP48L640_STATUS_WEL, false);
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if (ret)
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goto fail;
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kfree(cmd);
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return 0;
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fail:
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kfree(cmd);
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dev_err(&flash->spi->dev, "write fail with: %d", ret);
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return ret;
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};
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static int mchp48l640_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 mchp48l640_flash *flash = to_mchp48l640_flash(mtd);
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int ret;
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size_t wlen = 0;
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loff_t woff = to;
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size_t ws;
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size_t page_sz = flash->caps->page_size;
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/*
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* we set PRO bit (page rollover), but writing length > page size
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* does result in total chaos, so write in 32 byte chunks.
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*/
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while (wlen < len) {
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ws = min((len - wlen), page_sz);
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ret = mchp48l640_write_page(mtd, woff, ws, retlen, &buf[wlen]);
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if (ret)
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return ret;
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wlen += ws;
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woff += ws;
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}
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return 0;
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}
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static int mchp48l640_read_page(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 mchp48l640_flash *flash = to_mchp48l640_flash(mtd);
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unsigned char *cmd;
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int ret;
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int cmdlen;
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cmd = kmalloc((3 + len), GFP_KERNEL | GFP_DMA);
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if (!cmd)
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return -ENOMEM;
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ret = mchp48l640_wait_rdy(flash);
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if (ret)
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goto fail;
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mutex_lock(&flash->lock);
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cmdlen = mchp48l640_mkcmd(flash, MCHP48L640_CMD_READ, from, cmd);
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ret = spi_write_then_read(flash->spi, cmd, cmdlen, buf, len);
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mutex_unlock(&flash->lock);
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if (!ret)
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*retlen += len;
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kfree(cmd);
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return ret;
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fail:
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kfree(cmd);
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dev_err(&flash->spi->dev, "read fail with: %d", ret);
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return ret;
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}
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static int mchp48l640_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 mchp48l640_flash *flash = to_mchp48l640_flash(mtd);
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int ret;
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size_t wlen = 0;
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loff_t woff = from;
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size_t ws;
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size_t page_sz = flash->caps->page_size;
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/*
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* we set PRO bit (page rollover), but if read length > page size
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* does result in total chaos in result ...
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*/
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while (wlen < len) {
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ws = min((len - wlen), page_sz);
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ret = mchp48l640_read_page(mtd, woff, ws, retlen, &buf[wlen]);
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if (ret)
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return ret;
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wlen += ws;
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woff += ws;
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}
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return 0;
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};
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static const struct mchp48_caps mchp48l640_caps = {
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.size = SZ_8K,
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.page_size = 32,
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};
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static int mchp48l640_probe(struct spi_device *spi)
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{
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struct mchp48l640_flash *flash;
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struct flash_platform_data *data;
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int err;
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int status;
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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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err = mchp48l640_read_status(flash, &status);
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if (err)
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return err;
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err = mchp48l640_set_mode(flash);
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if (err)
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return err;
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data = dev_get_platdata(&spi->dev);
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flash->caps = of_device_get_match_data(&spi->dev);
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if (!flash->caps)
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flash->caps = &mchp48l640_caps;
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mtd_set_of_node(&flash->mtd, spi->dev.of_node);
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flash->mtd.dev.parent = &spi->dev;
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flash->mtd.type = MTD_RAM;
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flash->mtd.flags = MTD_CAP_RAM;
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flash->mtd.writesize = flash->caps->page_size;
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flash->mtd.size = flash->caps->size;
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flash->mtd._read = mchp48l640_read;
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flash->mtd._write = mchp48l640_write;
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err = mtd_device_register(&flash->mtd, data ? data->parts : NULL,
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data ? data->nr_parts : 0);
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if (err)
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return err;
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return 0;
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}
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static void mchp48l640_remove(struct spi_device *spi)
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{
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struct mchp48l640_flash *flash = spi_get_drvdata(spi);
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WARN_ON(mtd_device_unregister(&flash->mtd));
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}
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static const struct of_device_id mchp48l640_of_table[] = {
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{
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.compatible = "microchip,48l640",
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.data = &mchp48l640_caps,
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},
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{}
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};
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MODULE_DEVICE_TABLE(of, mchp48l640_of_table);
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static const struct spi_device_id mchp48l640_spi_ids[] = {
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{
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.name = "48l640",
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.driver_data = (kernel_ulong_t)&mchp48l640_caps,
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},
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{}
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};
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MODULE_DEVICE_TABLE(spi, mchp48l640_spi_ids);
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static struct spi_driver mchp48l640_driver = {
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.driver = {
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.name = "mchp48l640",
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.of_match_table = mchp48l640_of_table,
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},
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.probe = mchp48l640_probe,
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.remove = mchp48l640_remove,
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.id_table = mchp48l640_spi_ids,
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};
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module_spi_driver(mchp48l640_driver);
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MODULE_DESCRIPTION("MTD SPI driver for Microchip 48l640 EERAM chips");
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MODULE_AUTHOR("Heiko Schocher <hs@denx.de>");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("spi:mchp48l640");
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