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Message-ID: <20190801162229.28897-2-vigneshr@ti.com>
Date: Thu, 1 Aug 2019 21:52:27 +0530
From: Vignesh Raghavendra <vigneshr@...com>
To: Miquel Raynal <miquel.raynal@...tlin.com>,
Richard Weinberger <richard@....at>,
Vignesh Raghavendra <vigneshr@...com>,
Tudor Ambarus <tudor.ambarus@...rochip.com>
CC: Marek Vasut <marek.vasut@...il.com>,
Boris Brezillon <bbrezillon@...nel.org>,
<linux-kernel@...r.kernel.org>, <linux-mtd@...ts.infradead.org>,
Tomer Maimon <tmaimon77@...il.com>
Subject: [PATCH v4 1/3] 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.
Reviewed-by: Boris Brezillon <boris.brezillon@...labora.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@...com>
---
v4:
Avoid memcpy during READID
v3: new patch
drivers/mtd/spi-nor/spi-nor.c | 70 ++++++++++++++++++++---------------
include/linux/mtd/spi-nor.h | 7 +++-
2 files changed, 45 insertions(+), 32 deletions(-)
diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 03cc788511d5..e02376e1127b 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);
}
/**
@@ -1404,9 +1401,11 @@ static int write_sr_cr(struct spi_nor *nor, u8 *sr_cr)
{
int ret;
+ memcpy(nor->bouncebuf, sr_cr, 2);
+
write_enable(nor);
- ret = nor->write_reg(nor, SPINOR_OP_WRSR, sr_cr, 2);
+ ret = nor->write_reg(nor, SPINOR_OP_WRSR, nor->bouncebuf, 2);
if (ret < 0) {
dev_err(nor->dev,
"error while writing configuration register\n");
@@ -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;
}
@@ -2177,9 +2176,10 @@ 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;
const struct flash_info *info;
+ id = nor->bouncebuf;
tmp = nor->read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
if (tmp < 0) {
dev_err(nor->dev, "error %d reading JEDEC ID\n", tmp);
@@ -4121,6 +4121,16 @@ 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 9f57cdfcc93d..6b5956a7a65a 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);
--
2.22.0
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