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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: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
This commit is contained in:
Rafał Miłecki 2016-08-15 14:21:28 +02:00 committed by Brian Norris
parent 0e2ce9d3fc
commit 64ad46379f
1 changed files with 19 additions and 5 deletions
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24
drivers/mtd/devices/bcm47xxsflash.c
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@ -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->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;
/*
* 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;
}
switch (b47s->bcma_cc->capabilities & BCMA_CC_CAP_FLASHT) {
case BCMA_CC_FLASHT_STSER:
b47s->type = BCM47XXSFLASH_TYPE_ST;