Re: [PATCH 1/3] mtd: spi-nor: add optional DMA-safe bounce buffer for data transfer
From: Vignesh R <hidden>
Date: 2017-12-26 13:43:21
Also in:
linux-spi, lkml
Hi Cyrille, Thanks for doing this series! One comment below. On 24-Dec-17 10:06 AM, Cyrille Pitchen wrote: [...]
quoted hunk ↗ jump to hunk
diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c index 8bafd462f0ae..59f9fbd45234 100644 --- a/drivers/mtd/spi-nor/spi-nor.c +++ b/drivers/mtd/spi-nor/spi-nor.c@@ -14,8 +14,10 @@ #include <linux/errno.h> #include <linux/module.h> #include <linux/device.h> +#include <linux/highmem.h> #include <linux/mutex.h> #include <linux/math64.h> +#include <linux/mm.h> #include <linux/sizes.h> #include <linux/slab.h>@@ -1232,6 +1234,56 @@ static const struct flash_info spi_nor_ids[] = { { }, }; +static bool spi_nor_is_dma_safe(const void *buf) +{ + if (is_vmalloc_addr(buf)) + return false; + +#ifdef CONFIG_HIGHMEM + if ((unsigned long)buf >= PKMAP_BASE && + (unsigned long)buf < (PKMAP_BASE + (LAST_PKMAP * PAGE_SIZE))) + return false; +#endif + + return true; +} +
Better way would be to use virt_addr_valid():
static bool spi_nor_is_dma_safe(const void *buf)
{
return virt_addr_valid(buf);
}
Regards
Vignesh
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