Re: [PATCH v5 6/7] arm64: mm: Set ZONE_DMA size based on early IORT scan
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2020-10-30 18:01:13
Also in:
linux-acpi, linux-devicetree, linux-iommu, lkml
On Thu, Oct 29, 2020 at 06:25:49PM +0100, Nicolas Saenz Julienne wrote:
quoted hunk ↗ jump to hunk
diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c index 9929ff50c0c0..05fe4a076bab 100644 --- a/drivers/acpi/arm64/iort.c +++ b/drivers/acpi/arm64/iort.c@@ -1718,3 +1718,55 @@ void __init acpi_iort_init(void) iort_init_platform_devices(); } + +#ifdef CONFIG_ZONE_DMA +/* + * Check the IORT whether any devices exist whose DMA mask is < 32 bits. + * If so, return the smallest value encountered, or 32 otherwise. + */ +unsigned int __init acpi_iort_get_zone_dma_size(void) +{ + struct acpi_table_iort *iort; + struct acpi_iort_node *node, *end; + acpi_status status; + u8 limit = 32;
Nitpick: can we not return PHYS_ADDR_MAX here, for consistency with of_dma_get_max_cpu_address()? There wouldn't be any functional change. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel