Commit 64ad4637 authored by Rafał Miłecki's avatar Rafał Miłecki Committed by Brian Norris
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mtd: bcm47xxsflash: use uncached MMIO access for BCM53573 



BCM53573 is a new series of Broadcom's SoCs. It's based on ARM and uses
this old ChipCommon-based flash access. Early tests resulted in flash
corruptions that were tracked down to using cached MMIO for flash read
access. Switch to ioremap_nocache conditionally to support BCM53573 and
don't break performance on old MIPS devices.

Signed-off-by: default avatarRafał Miłecki <rafal@milecki.pl>
Reviewed-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
parent 0e2ce9d3

drivers/mtd/devices/bcm47xxsflash.c

+19 −5
Original line number Diff line number Diff line
@@ -296,16 +296,30 @@ static int bcm47xxsflash_bcma_probe(struct platform_device *pdev) 
		dev_err(dev, "can't request region for resource %pR\n", res);

		return -EBUSY;

	}



	b47s->bcma_cc = container_of(sflash, struct bcma_drv_cc, sflash);

	b47s->cc_read = bcm47xxsflash_bcma_cc_read;

	b47s->cc_write = bcm47xxsflash_bcma_cc_write;



	/*

	 * On old MIPS devices cache was magically invalidated when needed,

	 * allowing us to use cached access and gain some performance. Trying

	 * the same on ARM based BCM53573 results in flash corruptions, we need

	 * to use uncached access for it.

	 *

	 * It may be arch specific, but right now there is only 1 ARM SoC using

	 * this driver, so let's follow Broadcom's reference code and check

	 * ChipCommon revision.

	 */

	if (b47s->bcma_cc->core->id.rev == 54)

		b47s->window = ioremap_nocache(res->start, resource_size(res));

	else

		b47s->window = ioremap_cache(res->start, resource_size(res));

	if (!b47s->window) {

		dev_err(dev, "ioremap failed for resource %pR\n", res);

		return -ENOMEM;

	}



	b47s->bcma_cc = container_of(sflash, struct bcma_drv_cc, sflash);

	b47s->cc_read = bcm47xxsflash_bcma_cc_read;

	b47s->cc_write = bcm47xxsflash_bcma_cc_write;



	switch (b47s->bcma_cc->capabilities & BCMA_CC_CAP_FLASHT) {

	case BCMA_CC_FLASHT_STSER:

		b47s->type = BCM47XXSFLASH_TYPE_ST;

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