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-rw-r--r--Documentation/block/biodoc.txt19
-rw-r--r--Documentation/powerpc/dts-bindings/fsl/i2c.txt46
2 files changed, 37 insertions, 28 deletions
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index ecad6ee7570..6fab97ea7e6 100644
--- a/Documentation/block/biodoc.txt
+++ b/Documentation/block/biodoc.txt
@@ -1040,23 +1040,21 @@ Front merges are handled by the binary trees in AS and deadline schedulers.
iii. Plugging the queue to batch requests in anticipation of opportunities for
merge/sort optimizations
-This is just the same as in 2.4 so far, though per-device unplugging
-support is anticipated for 2.5. Also with a priority-based i/o scheduler,
-such decisions could be based on request priorities.
-
Plugging is an approach that the current i/o scheduling algorithm resorts to so
that it collects up enough requests in the queue to be able to take
advantage of the sorting/merging logic in the elevator. If the
queue is empty when a request comes in, then it plugs the request queue
-(sort of like plugging the bottom of a vessel to get fluid to build up)
+(sort of like plugging the bath tub of a vessel to get fluid to build up)
till it fills up with a few more requests, before starting to service
the requests. This provides an opportunity to merge/sort the requests before
passing them down to the device. There are various conditions when the queue is
unplugged (to open up the flow again), either through a scheduled task or
could be on demand. For example wait_on_buffer sets the unplugging going
-(by running tq_disk) so the read gets satisfied soon. So in the read case,
-the queue gets explicitly unplugged as part of waiting for completion,
-in fact all queues get unplugged as a side-effect.
+through sync_buffer() running blk_run_address_space(mapping). Or the caller
+can do it explicity through blk_unplug(bdev). So in the read case,
+the queue gets explicitly unplugged as part of waiting for completion on that
+buffer. For page driven IO, the address space ->sync_page() takes care of
+doing the blk_run_address_space().
Aside:
This is kind of controversial territory, as it's not clear if plugging is
@@ -1067,11 +1065,6 @@ Aside:
multi-page bios being queued in one shot, we may not need to wait to merge
a big request from the broken up pieces coming by.
- Per-queue granularity unplugging (still a Todo) may help reduce some of the
- concerns with just a single tq_disk flush approach. Something like
- blk_kick_queue() to unplug a specific queue (right away ?)
- or optionally, all queues, is in the plan.
-
4.4 I/O contexts
I/O contexts provide a dynamically allocated per process data area. They may
be used in I/O schedulers, and in the block layer (could be used for IO statis,
diff --git a/Documentation/powerpc/dts-bindings/fsl/i2c.txt b/Documentation/powerpc/dts-bindings/fsl/i2c.txt
index d0ab33e21fe..b6d2e21474f 100644
--- a/Documentation/powerpc/dts-bindings/fsl/i2c.txt
+++ b/Documentation/powerpc/dts-bindings/fsl/i2c.txt
@@ -7,8 +7,10 @@ Required properties :
Recommended properties :
- - compatible : Should be "fsl-i2c" for parts compatible with
- Freescale I2C specifications.
+ - compatible : compatibility list with 2 entries, the first should
+ be "fsl,CHIP-i2c" where CHIP is the name of a compatible processor,
+ e.g. mpc8313, mpc8543, mpc8544, mpc5200 or mpc5200b. The second one
+ should be "fsl-i2c".
- interrupts : <a b> where a is the interrupt number and b is a
field that represents an encoding of the sense and level
information for the interrupt. This should be encoded based on
@@ -16,17 +18,31 @@ Recommended properties :
controller you have.
- interrupt-parent : the phandle for the interrupt controller that
services interrupts for this device.
- - dfsrr : boolean; if defined, indicates that this I2C device has
- a digital filter sampling rate register
- - fsl5200-clocking : boolean; if defined, indicated that this device
- uses the FSL 5200 clocking mechanism.
-
-Example :
- i2c@3000 {
- interrupt-parent = <40000>;
- interrupts = <1b 3>;
- reg = <3000 18>;
- device_type = "i2c";
- compatible = "fsl-i2c";
- dfsrr;
+ - fsl,preserve-clocking : boolean; if defined, the clock settings
+ from the bootloader are preserved (not touched).
+ - clock-frequency : desired I2C bus clock frequency in Hz.
+
+Examples :
+
+ i2c@3d00 {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ compatible = "fsl,mpc5200b-i2c","fsl,mpc5200-i2c","fsl-i2c";
+ cell-index = <0>;
+ reg = <0x3d00 0x40>;
+ interrupts = <2 15 0>;
+ interrupt-parent = <&mpc5200_pic>;
+ fsl,preserve-clocking;
};
+
+ i2c@3100 {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ cell-index = <1>;
+ compatible = "fsl,mpc8544-i2c", "fsl-i2c";
+ reg = <0x3100 0x100>;
+ interrupts = <43 2>;
+ interrupt-parent = <&mpic>;
+ clock-frequency = <400000>;
+ };
+