From 89897f739d7b5e8d572909efc3c2ba7583b8aaba Mon Sep 17 00:00:00 2001 From: Hector Martin Date: Thu, 11 Feb 2021 21:41:56 +0900 Subject: [PATCH] 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 Reviewed-by: Rob Herring Signed-off-by: Hector Martin --- drivers/of/address.c | 43 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 41 insertions(+), 2 deletions(-) diff --git a/drivers/of/address.c b/drivers/of/address.c index 73ddf25..a2373fa 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; +} -- 2.7.4