Currently phram always uses ioremap(), but this is unnecessary when
normal memory is used. If the reserved-memory node does not specify the
no-map property, indicating it should be mapped as system RAM and
ioremap() cannot be used on it, use a cached mapping using
memremap(MEMREMAP_WB) instead.
On one of my systems this improves read performance by ~70%.
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>
---
drivers/mtd/devices/phram.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/mtd/devices/phram.c b/drivers/mtd/devices/phram.c
index 506e9edf5c85..89d74a1eff4f 100644
--- a/drivers/mtd/devices/phram.c
+++ b/drivers/mtd/devices/phram.c
@@ -34,6 +34,7 @@
struct phram_mtd_list {
struct mtd_info mtd;
struct list_head list;
+ bool cached;
};
static LIST_HEAD(phram_list);
@@ -96,6 +97,7 @@ static int register_device(struct platform_device *pdev, const char *name,
phys_addr_t start, size_t len, uint32_t erasesize)
{
struct device_node *np = pdev ? pdev->dev.of_node : NULL;
+ bool cached = np ? !of_property_read_bool(np, "no-map") : false;
struct phram_mtd_list *new;
int ret = -ENOMEM;
@@ -103,8 +105,13 @@ static int register_device(struct platform_device *pdev, const char *name,
if (!new)
goto out0;
+ new->cached = cached;
+
ret = -EIO;
- new->mtd.priv = ioremap(start, len);
+ if (cached)
+ new->mtd.priv = memremap(start, len, MEMREMAP_WB);
+ else
+ new->mtd.priv = ioremap(start, len);
if (!new->mtd.priv) {
pr_err("ioremap failed\n");
goto out1;
@@ -140,7 +147,7 @@ static int register_device(struct platform_device *pdev, const char *name,
return 0;
out2:
- iounmap(new->mtd.priv);
+ cached ? memunmap(new->mtd.priv) : iounmap(new->mtd.priv);
out1:
kfree(new);
out0:
@@ -362,7 +369,7 @@ static int phram_remove(struct platform_device *pdev)
struct phram_mtd_list *phram = platform_get_drvdata(pdev);
mtd_device_unregister(&phram->mtd);
- iounmap(phram->mtd.priv);
+ phram->cached ? memunmap(phram->mtd.priv) : iounmap(phram->mtd.priv);
kfree(phram);
return 0;
--
2.34.1
