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mtd: spi-nor: fsl-quadspi: dynamically map memory space for AHB read

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QSPI may failed to map enough memory (256MB) for AHB read in
previous implementation, especially in 3G/1G memory layout kernel.
Dynamically map memory to avoid such issue.

This implementation generally map QUADSPI_MAX_IOMAP (default 4MB) memory
for AHB read, it should be enough for common scenarios, and the side
effect (0.6% performance drop) is minor.

Previous implementation

root@imx6qdlsolo:~# dd if=/dev/mtd0 of=/dev/null bs=1K count=32K
32768+0 records in
32768+0 records out
33554432 bytes (34 MB) copied, 2.16006 s, 15.5 MB/s

root@imx6qdlsolo:~# dd if=/dev/mtd0 of=/dev/null bs=32M count=1
1+0 records in
1+0 records out
33554432 bytes (34 MB) copied, 1.43149 s, 23.4 MB/s

After applied the patch

root@imx6qdlsolo:~# dd if=/dev/mtd0 of=/dev/null bs=1K count=32K
32768+0 records in
32768+0 records out
33554432 bytes (34 MB) copied, 2.1743 s, 15.4 MB/s

root@imx6qdlsolo:~# dd if=/dev/mtd0 of=/dev/null bs=32M count=1
1+0 records in
1+0 records out
33554432 bytes (34 MB) copied, 1.43158 s, 23.4 MB/s

Signed-off-by: Han Xu <han.xu@freescale.com>
Signed-off-by: Frank Li <Frank.Li@freescale.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
This commit is contained in:
Han Xu 2015-08-04 10:25:22 -05:00 committed by Brian Norris
parent 4316302292
commit 49bd706aac
1 changed files with 48 additions and 7 deletions
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55
drivers/mtd/spi-nor/fsl-quadspi.c
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@ -192,6 +192,8 @@
#define SEQID_EN4B 10
#define SEQID_BRWR 11
#define QUADSPI_MIN_IOMAP SZ_4M
enum fsl_qspi_devtype {
FSL_QUADSPI_VYBRID,
FSL_QUADSPI_IMX6SX,
@ -223,8 +225,10 @@ struct fsl_qspi {
struct mtd_info mtd[FSL_QSPI_MAX_CHIP];
struct spi_nor nor[FSL_QSPI_MAX_CHIP];
void __iomem *iobase;
void __iomem *ahb_base; /* Used when read from AHB bus */
void __iomem *ahb_addr;
u32 memmap_phy;
u32 memmap_offs;
u32 memmap_len;
struct clk *clk, *clk_en;
struct device *dev;
struct completion c;
@ -732,11 +736,42 @@ static int fsl_qspi_read(struct spi_nor *nor, loff_t from,
struct fsl_qspi *q = nor->priv;
u8 cmd = nor->read_opcode;
dev_dbg(q->dev, "cmd [%x],read from (0x%p, 0x%.8x, 0x%.8x),len:%d\n",
cmd, q->ahb_base, q->chip_base_addr, (unsigned int)from, len);
/* if necessary,ioremap buffer before AHB read, */
if (!q->ahb_addr) {
q->memmap_offs = q->chip_base_addr + from;
q->memmap_len = len > QUADSPI_MIN_IOMAP ? len : QUADSPI_MIN_IOMAP;
q->ahb_addr = ioremap_nocache(
q->memmap_phy + q->memmap_offs,
q->memmap_len);
if (!q->ahb_addr) {
dev_err(q->dev, "ioremap failed\n");
return -ENOMEM;
}
/* ioremap if the data requested is out of range */
} else if (q->chip_base_addr + from < q->memmap_offs
|| q->chip_base_addr + from + len >
q->memmap_offs + q->memmap_len) {
iounmap(q->ahb_addr);
q->memmap_offs = q->chip_base_addr + from;
q->memmap_len = len > QUADSPI_MIN_IOMAP ? len : QUADSPI_MIN_IOMAP;
q->ahb_addr = ioremap_nocache(
q->memmap_phy + q->memmap_offs,
q->memmap_len);
if (!q->ahb_addr) {
dev_err(q->dev, "ioremap failed\n");
return -ENOMEM;
}
}
dev_dbg(q->dev, "cmd [%x],read from 0x%p, len:%d\n",
cmd, q->ahb_addr + q->chip_base_addr + from - q->memmap_offs,
len);
/* Read out the data directly from the AHB buffer.*/
memcpy(buf, q->ahb_base + q->chip_base_addr + from, len);
memcpy(buf, q->ahb_addr + q->chip_base_addr + from - q->memmap_offs,
len);
*retlen += len;
return 0;
@ -821,9 +856,11 @@ static int fsl_qspi_probe(struct platform_device *pdev)
res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
"QuadSPI-memory");
q->ahb_base = devm_ioremap_resource(dev, res);
if (IS_ERR(q->ahb_base))
return PTR_ERR(q->ahb_base);
if (!devm_request_mem_region(dev, res->start, resource_size(res),
res->name)) {
dev_err(dev, "can't request region for resource %pR\n", res);
return -EBUSY;
}
q->memmap_phy = res->start;
@ -989,6 +1026,10 @@ static int fsl_qspi_remove(struct platform_device *pdev)
mutex_destroy(&q->lock);
clk_unprepare(q->clk);
clk_unprepare(q->clk_en);
if (q->ahb_addr)
iounmap(q->ahb_addr);
return 0;
}