summaryrefslogtreecommitdiff
path: root/drivers/of/address.c
diff options
context:
space:
mode:
authorHector Martin <marcan@marcan.st>2021-02-11 15:41:56 +0300
committerHector Martin <marcan@marcan.st>2021-04-08 14:18:41 +0300
commit89897f739d7b5e8d572909efc3c2ba7583b8aaba (patch)
tree384e91b402a52f0e89cae60d889c42eaf4b7730f /drivers/of/address.c
parentb10eb2d50911f98a8f1cacf00b1b677339593f4c (diff)
downloadlinux-89897f739d7b5e8d572909efc3c2ba7583b8aaba.tar.xz
of/address: Add infrastructure to declare MMIO as non-posted
This implements the 'nonposted-mmio' boolean property. Placing this property in a bus marks all direct child devices as requiring non-posted MMIO mappings. If no such property is found, the default is posted MMIO. of_mmio_is_nonposted() performs this check to determine if a given device has requested non-posted MMIO. of_address_to_resource() uses this to set the IORESOURCE_MEM_NONPOSTED flag on resources that require non-posted MMIO. of_iomap() and of_io_request_and_map() then use this flag to pick the correct ioremap() variant. This mechanism is currently restricted to builds that support Apple ARM platforms, as an optimization. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Hector Martin <marcan@marcan.st>
Diffstat (limited to 'drivers/of/address.c')
-rw-r--r--drivers/of/address.c43
1 files changed, 41 insertions, 2 deletions
diff --git a/drivers/of/address.c b/drivers/of/address.c
index 73ddf2540f3f..a2373fa4a571 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -26,6 +26,7 @@ static struct of_bus *of_match_bus(struct device_node *np);
static int __of_address_to_resource(struct device_node *dev,
const __be32 *addrp, u64 size, unsigned int flags,
const char *name, struct resource *r);
+static bool of_mmio_is_nonposted(struct device_node *np);
/* Debug utility */
#ifdef DEBUG
@@ -847,6 +848,9 @@ static int __of_address_to_resource(struct device_node *dev,
return -EINVAL;
memset(r, 0, sizeof(struct resource));
+ if (of_mmio_is_nonposted(dev))
+ flags |= IORESOURCE_MEM_NONPOSTED;
+
r->start = taddr;
r->end = taddr + size - 1;
r->flags = flags;
@@ -896,7 +900,10 @@ void __iomem *of_iomap(struct device_node *np, int index)
if (of_address_to_resource(np, index, &res))
return NULL;
- return ioremap(res.start, resource_size(&res));
+ if (res.flags & IORESOURCE_MEM_NONPOSTED)
+ return ioremap_np(res.start, resource_size(&res));
+ else
+ return ioremap(res.start, resource_size(&res));
}
EXPORT_SYMBOL(of_iomap);
@@ -928,7 +935,11 @@ void __iomem *of_io_request_and_map(struct device_node *np, int index,
if (!request_mem_region(res.start, resource_size(&res), name))
return IOMEM_ERR_PTR(-EBUSY);
- mem = ioremap(res.start, resource_size(&res));
+ if (res.flags & IORESOURCE_MEM_NONPOSTED)
+ mem = ioremap_np(res.start, resource_size(&res));
+ else
+ mem = ioremap(res.start, resource_size(&res));
+
if (!mem) {
release_mem_region(res.start, resource_size(&res));
return IOMEM_ERR_PTR(-ENOMEM);
@@ -1094,3 +1105,31 @@ bool of_dma_is_coherent(struct device_node *np)
return false;
}
EXPORT_SYMBOL_GPL(of_dma_is_coherent);
+
+/**
+ * of_mmio_is_nonposted - Check if device uses non-posted MMIO
+ * @np: device node
+ *
+ * Returns true if the "nonposted-mmio" property was found for
+ * the device's bus.
+ *
+ * This is currently only enabled on builds that support Apple ARM devices, as
+ * an optimization.
+ */
+static bool of_mmio_is_nonposted(struct device_node *np)
+{
+ struct device_node *parent;
+ bool nonposted;
+
+ if (!IS_ENABLED(CONFIG_ARCH_APPLE))
+ return false;
+
+ parent = of_get_parent(np);
+ if (!parent)
+ return false;
+
+ nonposted = of_property_read_bool(parent, "nonposted-mmio");
+
+ of_node_put(parent);
+ return nonposted;
+}