[PATCH 1/4] of/fdt: Update zone_dma_bits when running in bcm2711
From: Nicolas Saenz Julienne <hidden>
Date: 2020-10-01 16:18:01
Also in:
linux-devicetree, linux-iommu, linux-mm, lkml
Subsystem:
open firmware and flattened device tree, the rest · Maintainers:
Rob Herring, Saravana Kannan, Linus Torvalds
arm64 wants to be able to set ZONE_DMA's size depending on the specific platform its being run on. Ideally this could be achieved in a smart way by parsing all dma-ranges and calculating the smaller DMA constraint in the system. Easier said than done. We compromised on a simpler solution as the only platform interested in using this is the Raspberry Pi 4. So update zone_dma_bits if the machine's compatible string matches Raspberry Pi 4's, otherwise let arm64's mm code deal with it. Signed-off-by: Nicolas Saenz Julienne <redacted> --- drivers/of/fdt.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 4602e467ca8b..cd0d115ef329 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c@@ -25,6 +25,7 @@ #include <linux/serial_core.h> #include <linux/sysfs.h> #include <linux/random.h> +#include <linux/dma-direct.h> /* for zone_dma_bits */ #include <asm/setup.h> /* for COMMAND_LINE_SIZE */ #include <asm/page.h>
@@ -1198,6 +1199,14 @@ void __init early_init_dt_scan_nodes(void) of_scan_flat_dt(early_init_dt_scan_memory, NULL); } +void __init early_init_dt_update_zone_dma_bits(void) +{ + unsigned long dt_root = of_get_flat_dt_root(); + + if (of_flat_dt_is_compatible(dt_root, "brcm,bcm2711")) + zone_dma_bits = 30; +} + bool __init early_init_dt_scan(void *params) { bool status;
@@ -1207,6 +1216,7 @@ bool __init early_init_dt_scan(void *params) return false; early_init_dt_scan_nodes(); + early_init_dt_update_zone_dma_bits(); return true; }
--
2.28.0
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