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Subject[PATCH v2 01/16] resource: Add System RAM resource type
Date
I/O resource type, IORESOURCE_MEM, is used for all types of
memory-mapped ranges, ex. System RAM, System ROM, Video RAM,
Persistent Memory, PCI Bus, PCI MMCONFIG, ACPI Tables, IOAPIC,
reserved, and so on. This requires walk_system_ram_range(),
walk_system_ram_res(), and region_intersects() to use strcmp()
against string "System RAM" to search for System RAM ranges in
the iomem table, which is inefficient. __ioremap_caller() and
reserve_memtype() on x86, for instance, call walk_system_ram_range()
for every request to check if a given range is in System RAM ranges.

However, adding a new I/O resource type for System RAM is not
a viable option [1]. There are approx. 3800 references to
IORESOURCE_MEM in the kernel/drivers, which make it very
difficult to distinguish their usages between new type and
IORESOURCE_MEM. The I/O resource types are also used by the
PNP subsystem. Therefore, this patch introduces an extended
I/O resource type, IORESOURCE_SYSTEM_RAM, which consists of
IORESOURCE_MEM and a new modifier flag IORESOURCE_SYSRAM [2].

To keep the code 'if (resource_type(r) == IORESOURCE_MEM)' to
work continuously for System RAM, resource_ext_type() is added
for extracting extended type bit(s).

Link[1]: http://lkml.kernel.org/r/<1449168859.9855.54.camel@hpe.com>
Link[2]: http://lkml.kernel.org/r/<CA+55aFy4WQrWexC4u2LxX9Mw2NVoznw7p3Yh=iF4Xtf7zKWnRw@mail.gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
---
include/linux/ioport.h | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 24bea08..4b65d94 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -49,12 +49,19 @@ struct resource {
#define IORESOURCE_WINDOW 0x00200000 /* forwarded by bridge */
#define IORESOURCE_MUXED 0x00400000 /* Resource is software muxed */

+#define IORESOURCE_EXT_TYPE_BITS 0x01000000 /* Resource extended types */
+#define IORESOURCE_SYSRAM 0x01000000 /* System RAM (modifier) */
+
#define IORESOURCE_EXCLUSIVE 0x08000000 /* Userland may not map this resource */
+
#define IORESOURCE_DISABLED 0x10000000
#define IORESOURCE_UNSET 0x20000000 /* No address assigned yet */
#define IORESOURCE_AUTO 0x40000000
#define IORESOURCE_BUSY 0x80000000 /* Driver has marked this resource busy */

+/* I/O resource extended types */
+#define IORESOURCE_SYSTEM_RAM (IORESOURCE_MEM|IORESOURCE_SYSRAM)
+
/* PnP IRQ specific bits (IORESOURCE_BITS) */
#define IORESOURCE_IRQ_HIGHEDGE (1<<0)
#define IORESOURCE_IRQ_LOWEDGE (1<<1)
@@ -170,6 +177,10 @@ static inline unsigned long resource_type(const struct resource *res)
{
return res->flags & IORESOURCE_TYPE_BITS;
}
+static inline unsigned long resource_ext_type(const struct resource *res)
+{
+ return res->flags & IORESOURCE_EXT_TYPE_BITS;
+}
/* True iff r1 completely contains r2 */
static inline bool resource_contains(struct resource *r1, struct resource *r2)
{

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