From f173f26a4d543fa57e6ed9505bbbbf9bec61f544 Mon Sep 17 00:00:00 2001 From: Vignesh Raghavendra Date: Tue, 6 Aug 2019 10:40:39 +0530 Subject: [PATCH] mtd: spi-nor: always use bounce buffer for register read/writes spi-mem layer expects all buffers passed to it to be DMA'able. But spi-nor layer mostly allocates buffers on stack for reading/writing to registers and therefore are not DMA'able. Introduce bounce buffer to be used to read/write to registers. This ensures that buffer passed to spi-mem layer during register read/writes is DMA'able. With this change nor->cmd-buf is no longer used, so drop it. Signed-off-by: Vignesh Raghavendra Reviewed-by: Boris Brezillon Signed-off-by: Tudor Ambarus --- drivers/mtd/spi-nor/spi-nor.c | 80 ++++++++++++++++++++++++------------------- include/linux/mtd/spi-nor.h | 7 ++-- 2 files changed, 49 insertions(+), 38 deletions(-) diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c index 03cc788..7f0831b 100644 --- a/drivers/mtd/spi-nor/spi-nor.c +++ b/drivers/mtd/spi-nor/spi-nor.c @@ -296,15 +296,14 @@ struct flash_info { static int read_sr(struct spi_nor *nor) { int ret; - u8 val; - ret = nor->read_reg(nor, SPINOR_OP_RDSR, &val, 1); + ret = nor->read_reg(nor, SPINOR_OP_RDSR, nor->bouncebuf, 1); if (ret < 0) { pr_err("error %d reading SR\n", (int) ret); return ret; } - return val; + return nor->bouncebuf[0]; } /* @@ -315,15 +314,14 @@ static int read_sr(struct spi_nor *nor) static int read_fsr(struct spi_nor *nor) { int ret; - u8 val; - ret = nor->read_reg(nor, SPINOR_OP_RDFSR, &val, 1); + ret = nor->read_reg(nor, SPINOR_OP_RDFSR, nor->bouncebuf, 1); if (ret < 0) { pr_err("error %d reading FSR\n", ret); return ret; } - return val; + return nor->bouncebuf[0]; } /* @@ -334,15 +332,14 @@ static int read_fsr(struct spi_nor *nor) static int read_cr(struct spi_nor *nor) { int ret; - u8 val; - ret = nor->read_reg(nor, SPINOR_OP_RDCR, &val, 1); + ret = nor->read_reg(nor, SPINOR_OP_RDCR, nor->bouncebuf, 1); if (ret < 0) { dev_err(nor->dev, "error %d reading CR\n", ret); return ret; } - return val; + return nor->bouncebuf[0]; } /* @@ -351,8 +348,8 @@ static int read_cr(struct spi_nor *nor) */ static int write_sr(struct spi_nor *nor, u8 val) { - nor->cmd_buf[0] = val; - return nor->write_reg(nor, SPINOR_OP_WRSR, nor->cmd_buf, 1); + nor->bouncebuf[0] = val; + return nor->write_reg(nor, SPINOR_OP_WRSR, nor->bouncebuf, 1); } /* @@ -500,31 +497,31 @@ static int set_4byte(struct spi_nor *nor, bool enable) * We must clear the register to enable normal behavior. */ write_enable(nor); - nor->cmd_buf[0] = 0; - nor->write_reg(nor, SPINOR_OP_WREAR, nor->cmd_buf, 1); + nor->bouncebuf[0] = 0; + nor->write_reg(nor, SPINOR_OP_WREAR, + nor->bouncebuf, 1); write_disable(nor); } return status; default: /* Spansion style */ - nor->cmd_buf[0] = enable << 7; - return nor->write_reg(nor, SPINOR_OP_BRWR, nor->cmd_buf, 1); + nor->bouncebuf[0] = enable << 7; + return nor->write_reg(nor, SPINOR_OP_BRWR, nor->bouncebuf, 1); } } static int s3an_sr_ready(struct spi_nor *nor) { int ret; - u8 val; - ret = nor->read_reg(nor, SPINOR_OP_XRDSR, &val, 1); + ret = nor->read_reg(nor, SPINOR_OP_XRDSR, nor->bouncebuf, 1); if (ret < 0) { dev_err(nor->dev, "error %d reading XRDSR\n", (int) ret); return ret; } - return !!(val & XSR_RDY); + return !!(nor->bouncebuf[0] & XSR_RDY); } static int spi_nor_sr_ready(struct spi_nor *nor) @@ -683,7 +680,6 @@ static loff_t spi_nor_s3an_addr_convert(struct spi_nor *nor, unsigned int addr) */ static int spi_nor_erase_sector(struct spi_nor *nor, u32 addr) { - u8 buf[SPI_NOR_MAX_ADDR_WIDTH]; int i; if (nor->flags & SNOR_F_S3AN_ADDR_DEFAULT) @@ -697,11 +693,12 @@ static int spi_nor_erase_sector(struct spi_nor *nor, u32 addr) * control */ for (i = nor->addr_width - 1; i >= 0; i--) { - buf[i] = addr & 0xff; + nor->bouncebuf[i] = addr & 0xff; addr >>= 8; } - return nor->write_reg(nor, nor->erase_opcode, buf, nor->addr_width); + return nor->write_reg(nor, nor->erase_opcode, nor->bouncebuf, + nor->addr_width); } /** @@ -1485,9 +1482,11 @@ static int macronix_quad_enable(struct spi_nor *nor) */ static int spansion_quad_enable(struct spi_nor *nor) { - u8 sr_cr[2] = {0, CR_QUAD_EN_SPAN}; + u8 *sr_cr = nor->bouncebuf; int ret; + sr_cr[0] = 0; + sr_cr[1] = CR_QUAD_EN_SPAN; ret = write_sr_cr(nor, sr_cr); if (ret) return ret; @@ -1517,7 +1516,7 @@ static int spansion_quad_enable(struct spi_nor *nor) */ static int spansion_no_read_cr_quad_enable(struct spi_nor *nor) { - u8 sr_cr[2]; + u8 *sr_cr = nor->bouncebuf; int ret; /* Keep the current value of the Status Register. */ @@ -1548,7 +1547,7 @@ static int spansion_no_read_cr_quad_enable(struct spi_nor *nor) static int spansion_read_cr_quad_enable(struct spi_nor *nor) { struct device *dev = nor->dev; - u8 sr_cr[2]; + u8 *sr_cr = nor->bouncebuf; int ret; /* Check current Quad Enable bit value. */ @@ -1599,22 +1598,22 @@ static int spansion_read_cr_quad_enable(struct spi_nor *nor) */ static int sr2_bit7_quad_enable(struct spi_nor *nor) { - u8 sr2; + u8 *sr2 = nor->bouncebuf; int ret; /* Check current Quad Enable bit value. */ - ret = nor->read_reg(nor, SPINOR_OP_RDSR2, &sr2, 1); + ret = nor->read_reg(nor, SPINOR_OP_RDSR2, sr2, 1); if (ret) return ret; - if (sr2 & SR2_QUAD_EN_BIT7) + if (*sr2 & SR2_QUAD_EN_BIT7) return 0; /* Update the Quad Enable bit. */ - sr2 |= SR2_QUAD_EN_BIT7; + *sr2 |= SR2_QUAD_EN_BIT7; write_enable(nor); - ret = nor->write_reg(nor, SPINOR_OP_WRSR2, &sr2, 1); + ret = nor->write_reg(nor, SPINOR_OP_WRSR2, sr2, 1); if (ret < 0) { dev_err(nor->dev, "error while writing status register 2\n"); return -EINVAL; @@ -1627,8 +1626,8 @@ static int sr2_bit7_quad_enable(struct spi_nor *nor) } /* Read back and check it. */ - ret = nor->read_reg(nor, SPINOR_OP_RDSR2, &sr2, 1); - if (!(ret > 0 && (sr2 & SR2_QUAD_EN_BIT7))) { + ret = nor->read_reg(nor, SPINOR_OP_RDSR2, sr2, 1); + if (!(ret > 0 && (*sr2 & SR2_QUAD_EN_BIT7))) { dev_err(nor->dev, "SR2 Quad bit not set\n"); return -EINVAL; } @@ -1687,7 +1686,7 @@ static int spi_nor_spansion_clear_sr_bp(struct spi_nor *nor) { int ret; u8 mask = SR_BP2 | SR_BP1 | SR_BP0; - u8 sr_cr[2] = {0}; + u8 *sr_cr = nor->bouncebuf; /* Check current Quad Enable bit value. */ ret = read_cr(nor); @@ -2177,7 +2176,7 @@ static const struct flash_info spi_nor_ids[] = { static const struct flash_info *spi_nor_read_id(struct spi_nor *nor) { int tmp; - u8 id[SPI_NOR_MAX_ID_LEN]; + u8 *id = nor->bouncebuf; const struct flash_info *info; tmp = nor->read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN); @@ -2393,9 +2392,8 @@ static int spi_nor_check(struct spi_nor *nor) static int s3an_nor_scan(struct spi_nor *nor) { int ret; - u8 val; - ret = nor->read_reg(nor, SPINOR_OP_XRDSR, &val, 1); + ret = nor->read_reg(nor, SPINOR_OP_XRDSR, nor->bouncebuf, 1); if (ret < 0) { dev_err(nor->dev, "error %d reading XRDSR\n", (int) ret); return ret; @@ -2417,7 +2415,7 @@ static int s3an_nor_scan(struct spi_nor *nor) * The current addressing mode can be read from the XRDSR register * and should not be changed, because is a destructive operation. */ - if (val & XSR_PAGESIZE) { + if (nor->bouncebuf[0] & XSR_PAGESIZE) { /* Flash in Power of 2 mode */ nor->page_size = (nor->page_size == 264) ? 256 : 512; nor->mtd.writebufsize = nor->page_size; @@ -4121,6 +4119,16 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, nor->read_proto = SNOR_PROTO_1_1_1; nor->write_proto = SNOR_PROTO_1_1_1; + /* + * We need the bounce buffer early to read/write registers when going + * through the spi-mem layer (buffers have to be DMA-able). + */ + nor->bouncebuf_size = PAGE_SIZE; + nor->bouncebuf = devm_kmalloc(dev, nor->bouncebuf_size, + GFP_KERNEL); + if (!nor->bouncebuf) + return -ENOMEM; + if (name) info = spi_nor_match_id(name); /* Try to auto-detect if chip name wasn't specified or not found */ diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h index 9f57cdf..6b5956a7 100644 --- a/include/linux/mtd/spi-nor.h +++ b/include/linux/mtd/spi-nor.h @@ -344,6 +344,9 @@ struct flash_info; * @mtd: point to a mtd_info structure * @lock: the lock for the read/write/erase/lock/unlock operations * @dev: point to a spi device, or a spi nor controller device. + * @bouncebuf: bounce buffer used when the buffer passed by the MTD + * layer is not DMA-able + * @bouncebuf_size: size of the bounce buffer * @info: spi-nor part JDEC MFR id and other info * @page_size: the page size of the SPI NOR * @addr_width: number of address bytes @@ -356,7 +359,6 @@ struct flash_info; * @read_proto: the SPI protocol for read operations * @write_proto: the SPI protocol for write operations * @reg_proto the SPI protocol for read_reg/write_reg/erase operations - * @cmd_buf: used by the write_reg * @erase_map: the erase map of the SPI NOR * @prepare: [OPTIONAL] do some preparations for the * read/write/erase/lock/unlock operations @@ -382,6 +384,8 @@ struct spi_nor { struct mtd_info mtd; struct mutex lock; struct device *dev; + u8 *bouncebuf; + size_t bouncebuf_size; const struct flash_info *info; u32 page_size; u8 addr_width; @@ -394,7 +398,6 @@ struct spi_nor { enum spi_nor_protocol reg_proto; bool sst_write_second; u32 flags; - u8 cmd_buf[SPI_NOR_MAX_CMD_SIZE]; struct spi_nor_erase_map erase_map; int (*prepare)(struct spi_nor *nor, enum spi_nor_ops ops); -- 2.7.4