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374 lines
8.5 KiB
374 lines
8.5 KiB
// 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 <[email protected]> |
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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 int 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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return 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 struct spi_driver mchp48l640_driver = { |
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.driver = { |
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.name = "mchp48l640", |
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.of_match_table = of_match_ptr(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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}; |
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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 <[email protected]>"); |
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MODULE_LICENSE("GPL v2"); |
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MODULE_ALIAS("spi:mchp48l640");
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