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Commit 49bd706a authored by Han Xu's avatar Han Xu Committed by Brian Norris
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mtd: spi-nor: fsl-quadspi: dynamically map memory space for AHB read 



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: default avatarHan Xu <han.xu@freescale.com>
Signed-off-by: default avatarFrank Li <Frank.Li@freescale.com>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
parent 43163022

drivers/mtd/spi-nor/fsl-quadspi.c

+48 −7
Original line number Diff line number Diff line
@@ -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;

}