[PATCH v6 net-next 01/10] misc: sram: add optional ioremap without write combining

Gregory CLEMENT
2016-03-14T08:39:31Z

From: Marcin Wojtas <mw@semihalf.com>

Some SRAM users may require non-bufferable access to the memory, which is
impossible, because devm_ioremap_wc() is used for setting sram->virt_base.

This commit adds optional flag 'no-memory-wc', which allow to choose remap
method, using DT property. Documentation is updated accordingly.

Signed-off-by: Marcin Wojtas <mw@semihalf.com>
---
Documentation/devicetree/bindings/sram/sram.txt | 5 +++++
drivers/misc/sram.c | 5 ++++-
2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/sram/sram.txt b/Documentation/devicetree/bindings/sram/sram.txt
index 42ee9438b771..227e3a341af1 100644
--- a/Documentation/devicetree/bindings/sram/sram.txt
+++ b/Documentation/devicetree/bindings/sram/sram.txt
@@ -25,6 +25,11 @@ Required properties in the sram node:
- ranges : standard definition, should translate from local addresses
within the sram to bus addresses

+Optional properties in the sram node:
+
+- no-memory-wc : the flag indicating, that SRAM memory region has not to
+ be remapped as write combining. WC is used by default.
+
Required properties in the area nodes:

- reg : iomem address range, relative to the SRAM range
diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c
index 736dae715dbf..69cdabea9c03 100644
--- a/drivers/misc/sram.c
+++ b/drivers/misc/sram.c
@@ -360,7 +360,10 @@ static int sram_probe(struct platform_device *pdev)
return -EBUSY;
}

- sram->virt_base = devm_ioremap_wc(sram->dev, res->start, size);
+ if (of_property_read_bool(pdev->dev.of_node, "no-memory-wc"))
+ sram->virt_base = devm_ioremap(sram->dev, res->start, size);
+ else
+ sram->virt_base = devm_ioremap_wc(sram->dev, res->start, size);
if (IS_ERR(sram->virt_base))
return PTR_ERR(sram->virt_base);

--
2.5.0