New of_io_release_and_unmap()
Hello folks,
I notice that io_request_and_map has no inverse. I would like to add a new function to undo what it does.
Joshua Clayton (1):
of/address: Add of_io_release_and_unmap()
drivers/of/address.c | 29 +++++++++++++++++++++++++++++ include/linux/of_address.h | 2 ++ 2 files changed, 31 insertions(+)
Signature · 1 line
2.1.0
PATCH 1/1 of/address: Add of_io_release_and_unmap()
New Fumction of_io_release_an_unmap frees resources and io memory allocated by io_request_and_map()
--- drivers/of/address.c | 29 +++++++++++++++++++++++++++++ include/linux/of_address.h | 2 ++ 2 files changed, 31 insertions(+)
drivers/of/address.c +29 -0
@@ -872,6 +872,7 @@ EXPORT_SYMBOL(of_iomap);/* * of_io_request_and_map - Requests a resource and maps the memory mapped IO * for a given device_node +* Call of_io_release_and_unmap() to free the memory * @device: the device whose io range will be mapped * @index: index of the io range * @name: name of the resource
@@ -882,6 +883,10 @@ EXPORT_SYMBOL(of_iomap);* base = of_io_request_and_map(node, 0, "foo"); * if (IS_ERR(base)) * return PTR_ERR(base); +* +* ... +* +* return of_io_request_and_map(node, 0, base); */ void __iomem *of_io_request_and_map (struct device_node *np,int index,const char *name)
@@ -906,6 +911,30 @@ void __iomem *of_io_request_and_map(struct device_node *np, int index,EXPORT_SYMBOL (of_io_request_and_map);/** +* of_io_release_and_unmap - Unmap memory and release resource +* associated with a device node +* Use this function to free memory requested by of_io_request_and_map() +* See the Usage example for of_io_request_and_map +* +*/ +int of_io_release_and_unmap (struct device_node *np,int index, +void __iomem *addr) +{ +struct resource res; +int ret =0 ; + + ret =of_address_to_resource (np, index, &res); +if (ret) +return ret; + +iounmap (addr); +release_mem_region (res.start,resource_size (&res)); + +return ret; +} +EXPORT_SYMBOL (of_io_release_and_unmap); + +/** * of_dma_get_range - Get DMA range info * @np: device node to get DMA range info * @dma_addr: pointer to store initial DMA address of DMA range
include/linux/of_address.h +2 -0
@@ -107,6 +107,8 @@ extern int of_address_to_resource(struct device_node *dev, int index,void __iomem *of_iomap (struct device_node *node,int index);void __iomem *of_io_request_and_map (struct device_node *device,int index,const char *name); +int of_io_release_and_unmap (struct device_node *np,int index, +void __iomem *addr);#else #include <linux/io.h>
Signature · 1 line
2.1.0
Quoted 4 lines · On Wednesday 25 February 2015 11:20:41 Joshua Clayton wrote:
Hello folks,
I notice thatio_request_and_maphas no inverse. I would like to add a new function to undo what it does.
What do you want to use this for? So far all users are in essential drivers (clk and clocksource) that result in a boot failure if this goes wrong.
Normal drivers can probably always use devm_ioremap_resource(), which has an automatic cleanup.
Arnd
Quoted 9 lines · Arnd Bergmann
Quoted 4 lines · On Wednesday 25 February 2015 11:20:41 Joshua Clayton wrote:
Hello folks,
I notice thatio_request_and_maphas no inverse. I would like to add a new function to undo what it does.What do you want to use this for? So far all users are in essential drivers (clk and clocksource) that result in a boot failure if this goes wrong.
That explains a lot. It looks (to my n00b eye) like this function leaks some references, which is more ok if the ref counters should never be decremented to 0.
Quoted 3 lines
Normal drivers can probably always use
devm_ioremap_resource(), which has an automatic cleanup.
Hmmm.
My use case is indeed a normal driver, which could definitely use devm_ioremap_resource()
Quoted 1 line
Arnd
That would leave only "completeness" as a reason. Probably not needed. --
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