Collected driver model bug-fixes and docs

index 6edb2e7..a53f69a 100644
@@ -1000,6 +1000,7 @@ The following options need to be configured:
 		CONFIG_CMD_IMLS		  List all images found in NOR flash
 		CONFIG_CMD_IMLS_NAND	* List all images found in NAND flash
 		CONFIG_CMD_IMMAP	* IMMR dump support
+		CONFIG_CMD_IOTRACE	* I/O tracing for debugging
 		CONFIG_CMD_IMPORTENV	* import an environment
 		CONFIG_CMD_INI		* import data from an ini file into the env
 		CONFIG_CMD_IRQ		* irqinfo

@@ -1171,6 +1172,28 @@ The following options need to be configured:
 		Note that if the GPIO device uses I2C, then the I2C interface
 		must also be configured. See I2C Support, below.
 
+- I/O tracing:
+		When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
+		accesses and can checksum them or write a list of them out
+		to memory. See the 'iotrace' command for details. This is
+		useful for testing device drivers since it can confirm that
+		the driver behaves the same way before and after a code
+		change. Currently this is supported on sandbox and arm. To
+		add support for your architecture, add '#include <iotrace.h>'
+		to the bottom of arch/<arch>/include/asm/io.h and test.
+
+		Example output from the 'iotrace stats' command is below.
+		Note that if the trace buffer is exhausted, the checksum will
+		still continue to operate.
+
+			iotrace is enabled
+			Start:  10000000	(buffer start address)
+			Size:   00010000	(buffer size)
+			Offset: 00000120	(current buffer offset)
+			Output: 10000120	(start + offset)
+			Count:  00000018	(number of trace records)
+			CRC32:  9526fb66	(CRC32 of all trace records)
+
 - Timestamp Support:
 
 		When CONFIG_TIMESTAMP is selected, the timestamp

index 391a8d6..7e192c7 100644
@@ -114,6 +114,7 @@ obj-$(CONFIG_CMD_FUSE) += cmd_fuse.o
 obj-$(CONFIG_CMD_GETTIME) += cmd_gettime.o
 obj-$(CONFIG_CMD_GPIO) += cmd_gpio.o
 obj-$(CONFIG_CMD_I2C) += cmd_i2c.o
+obj-$(CONFIG_CMD_IOTRACE) += cmd_iotrace.o
 obj-$(CONFIG_CMD_HASH) += cmd_hash.o
 obj-$(CONFIG_CMD_IDE) += cmd_ide.o
 obj-$(CONFIG_CMD_IMMAP) += cmd_immap.o

@@ -261,6 +262,7 @@ obj-$(CONFIG_ANDROID_BOOT_IMAGE) += image-android.o
 obj-$(CONFIG_OF_LIBFDT) += image-fdt.o
 obj-$(CONFIG_FIT) += image-fit.o
 obj-$(CONFIG_FIT_SIGNATURE) += image-sig.o
+obj-$(CONFIG_IO_TRACE) += iotrace.o
 obj-y += memsize.o
 obj-y += stdio.o
 

new file mode 120000
index 0000000..0cecb3d
@@ -0,0 +1 @@
+../../../../include/dt-bindings
\ No newline at end of file

new file mode 120000
index 0000000..0cecb3d
@@ -0,0 +1 @@
+../../../../include/dt-bindings
\ No newline at end of file

new file mode 120000
index 0000000..0cecb3d
@@ -0,0 +1 @@
+../../../../include/dt-bindings
\ No newline at end of file

new file mode 120000
index 0000000..0cecb3d
@@ -0,0 +1 @@
+../../../../include/dt-bindings
\ No newline at end of file

index a04439d..722afed 100644
@@ -153,6 +153,7 @@ ld_flags       = $(LDFLAGS) $(ldflags-y)
 # Modified for U-Boot
 dtc_cpp_flags  = -Wp,-MD,$(depfile).pre.tmp -nostdinc                    \
 		 -I$(srctree)/arch/$(ARCH)/dts                           \
+		 -I$(srctree)/arch/$(ARCH)/dts/include                   \
 		 -undef -D__DTS__
 
 # Finds the multi-part object the current object will be linked into

index dcecb9a..4af89b0 100644
@@ -315,7 +315,7 @@ is little or no 'driver model' code to write.
 - Moved some data from code into data structure - e.g. store a pointer to
 the driver operations structure in the driver, rather than passing it
 to the driver bind function.
-- Rename some structures to make them more similar to Linux (struct device
+- Rename some structures to make them more similar to Linux (struct udevice
 instead of struct instance, struct platdata, etc.)
 - Change the name 'core' to 'uclass', meaning U-Boot class. It seems that
 this concept relates to a class of drivers (or a subsystem). We shouldn't

index a53f69a..c7b911b 100644
@@ -5310,6 +5310,11 @@ Information structure as we define in include/asm-<arch>/u-boot.h,
 and make sure that your definition of IMAP_ADDR uses the same value
 as your U-Boot configuration in CONFIG_SYS_IMMR.
 
+Note that U-Boot now has a driver model, a unified model for drivers.
+If you are adding a new driver, plumb it into driver model. If there
+is no uclass available, you are encouraged to create one. See
+doc/driver-model.
+
 
 Configuring the Linux kernel:
 -----------------------------

index 4e9afe6..c0f2135 100644
@@ -15,4 +15,6 @@ obj-$(CONFIG_DM_TEST) += ut.o
 # subsystem you must add sandbox tests here.
 obj-$(CONFIG_DM_TEST) += core.o
 obj-$(CONFIG_DM_TEST) += ut.o
+ifneq ($(CONFIG_SANDBOX),)
 obj-$(CONFIG_DM_GPIO) += gpio.o
+endif

index f52fcf1..59434e0 100644
@@ -1,3 +1,6 @@
+#include <dt-bindings/gpio/tegra-gpio.h>
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
 #include "skeleton.dtsi"
 
 / {

@@ -46,17 +49,17 @@
 			      0 143 0x04>;
 	};
 
-	gpio: gpio {
+	gpio: gpio at 6000d000 {
 		compatible = "nvidia,tegra114-gpio", "nvidia,tegra30-gpio";
 		reg = <0x6000d000 0x1000>;
-		interrupts = <0 32 0x04
-			      0 33 0x04
-			      0 34 0x04
-			      0 35 0x04
-			      0 55 0x04
-			      0 87 0x04
-			      0 89 0x04
-			      0 125 0x04>;
+		interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 33 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 34 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 35 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 89 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 125 IRQ_TYPE_LEVEL_HIGH>;
 		#gpio-cells = <2>;
 		gpio-controller;
 		#interrupt-cells = <2>;

index 18a8b24..4561c5f 100644
@@ -1,3 +1,6 @@
+#include <dt-bindings/gpio/tegra-gpio.h>
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
 #include "skeleton.dtsi"
 
 / {

@@ -49,14 +52,14 @@
 	gpio: gpio at 6000d000 {
 		compatible = "nvidia,tegra124-gpio", "nvidia,tegra30-gpio";
 		reg = <0x6000d000 0x1000>;
-		interrupts = <0 32 0x04
-			      0 33 0x04
-			      0 34 0x04
-			      0 35 0x04
-			      0 55 0x04
-			      0 87 0x04
-			      0 89 0x04
-			      0 125 0x04>;
+		interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 33 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 34 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 35 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 89 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 125 IRQ_TYPE_LEVEL_HIGH>;
 		#gpio-cells = <2>;
 		gpio-controller;
 		#interrupt-cells = <2>;

index 3805750..a524f6e 100644
@@ -1,3 +1,6 @@
+#include <dt-bindings/gpio/tegra-gpio.h>
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
 #include "skeleton.dtsi"
 
 / {

@@ -139,10 +142,18 @@
 
 	gpio: gpio at 6000d000 {
 		compatible = "nvidia,tegra20-gpio";
-		reg = < 0x6000d000 0x1000 >;
-		interrupts = < 64 65 66 67 87 119 121 >;
+		reg = <0x6000d000 0x1000>;
+		interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 33 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 34 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 35 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 89 IRQ_TYPE_LEVEL_HIGH>;
 		#gpio-cells = <2>;
 		gpio-controller;
+		#interrupt-cells = <2>;
+		interrupt-controller;
 	};
 
 	pinmux: pinmux at 70000000 {

index fee1c36..7be3791 100644
@@ -1,3 +1,6 @@
+#include <dt-bindings/gpio/tegra-gpio.h>
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
 #include "skeleton.dtsi"
 
 / {

@@ -47,17 +50,17 @@
 		clocks = <&tegra_car 34>;
 	};
 
-	gpio: gpio {
+	gpio: gpio at 6000d000 {
 		compatible = "nvidia,tegra30-gpio";
 		reg = <0x6000d000 0x1000>;
-		interrupts = <0 32 0x04
-			      0 33 0x04
-			      0 34 0x04
-			      0 35 0x04
-			      0 55 0x04
-			      0 87 0x04
-			      0 89 0x04
-			      0 125 0x04>;
+		interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 33 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 34 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 35 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 89 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 125 IRQ_TYPE_LEVEL_HIGH>;
 		#gpio-cells = <2>;
 		gpio-controller;
 		#interrupt-cells = <2>;

index 4af89b0..884acef 100644
@@ -222,7 +222,44 @@ device tree) and probe.
 Platform Data
 -------------
 
-Where does the platform data come from? See demo-pdata.c which
+Platform data is like Linux platform data, if you are familiar with that.
+It provides the board-specific information to start up a device.
+
+Why is this information not just stored in the device driver itself? The
+idea is that the device driver is generic, and can in principle operate on
+any board that has that type of device. For example, with modern
+highly-complex SoCs it is common for the IP to come from an IP vendor, and
+therefore (for example) the MMC controller may be the same on chips from
+different vendors. It makes no sense to write independent drivers for the
+MMC controller on each vendor's SoC, when they are all almost the same.
+Similarly, we may have 6 UARTs in an SoC, all of which are mostly the same,
+but lie at different addresses in the address space.
+
+Using the UART example, we have a single driver and it is instantiated 6
+times by supplying 6 lots of platform data. Each lot of platform data
+gives the driver name and a pointer to a structure containing information
+about this instance - e.g. the address of the register space. It may be that
+one of the UARTS supports RS-485 operation - this can be added as a flag in
+the platform data, which is set for this one port and clear for the rest.
+
+Think of your driver as a generic piece of code which knows how to talk to
+a device, but needs to know where it is, any variant/option information and
+so on. Platform data provides this link between the generic piece of code
+and the specific way it is bound on a particular board.
+
+Examples of platform data include:
+
+   - The base address of the IP block's register space
+   - Configuration options, like:
+         - the SPI polarity and maximum speed for a SPI controller
+         - the I2C speed to use for an I2C device
+         - the number of GPIOs available in a GPIO device
+
+Where does the platform data come from? It is either held in a structure
+which is compiled into U-Boot, or it can be parsed from the Device Tree
+(see 'Device Tree' below).
+
+For an example of how it can be compiled in, see demo-pdata.c which
 sets up a table of driver names and their associated platform data.
 The data can be interpreted by the drivers however they like - it is
 basically a communication scheme between the board-specific code and

@@ -259,21 +296,30 @@ following device tree fragment:
 		sides = <4>;
 	};
 
+This means that instead of having lots of U_BOOT_DEVICE() declarations in
+the board file, we put these in the device tree. This approach allows a lot
+more generality, since the same board file can support many types of boards
+(e,g. with the same SoC) just by using different device trees. An added
+benefit is that the Linux device tree can be used, thus further simplifying
+the task of board-bring up either for U-Boot or Linux devs (whoever gets to
+the baord first!).
 
 The easiest way to make this work it to add a few members to the driver:
 
 	.platdata_auto_alloc_size = sizeof(struct dm_test_pdata),
 	.ofdata_to_platdata = testfdt_ofdata_to_platdata,
-	.probe	= testfdt_drv_probe,
 
 The 'auto_alloc' feature allowed space for the platdata to be allocated
-and zeroed before the driver's ofdata_to_platdata method is called. This
-method reads the information out of the device tree and puts it in
-dev->platdata. Then the probe method is called to set up the device.
+and zeroed before the driver's ofdata_to_platdata() method is called. The
+ofdata_to_platdata() method, which the driver write supplies, should parse
+the device tree node for this device and place it in dev->platdata. Thus
+when the probe method is called later (to set up the device ready for use)
+the platform data will be present.
 
 Note that both methods are optional. If you provide an ofdata_to_platdata
-method then it wlil be called first (after bind). If you provide a probe
-method it will be called next.
+method then it wlil be called first (during activation). If you provide a
+probe method it will be called next. See Driver Lifecycle below for more
+details.
 
 If you don't want to have the platdata automatically allocated then you
 can leave out platdata_auto_alloc_size. In this case you can use malloc

@@ -295,6 +341,161 @@ numbering comes from include/dm/uclass.h. To add a new uclass, add to the
 end of the enum there, then declare your uclass as above.
 
 
+Driver Lifecycle
+----------------
+
+Here are the stages that a device goes through in driver model. Note that all
+methods mentioned here are optional - e.g. if there is no probe() method for
+a device then it will not be called. A simple device may have very few
+methods actually defined.
+
+1. Bind stage
+
+A device and its driver are bound using one of these two methods:
+
+   - Scan the U_BOOT_DEVICE() definitions. U-Boot It looks up the
+name specified by each, to find the appropriate driver. It then calls
+device_bind() to create a new device and bind' it to its driver. This will
+call the device's bind() method.
+
+   - Scan through the device tree definitions. U-Boot looks at top-level
+nodes in the the device tree. It looks at the compatible string in each node
+and uses the of_match part of the U_BOOT_DRIVER() structure to find the
+right driver for each node. It then calls device_bind() to bind the
+newly-created device to its driver (thereby creating a device structure).
+This will also call the device's bind() method.
+
+At this point all the devices are known, and bound to their drivers. There
+is a 'struct udevice' allocated for all devices. However, nothing has been
+activated (except for the root device). Each bound device that was created
+from a U_BOOT_DEVICE() declaration will hold the platdata pointer specified
+in that declaration. For a bound device created from the device tree,
+platdata will be NULL, but of_offset will be the offset of the device tree
+node that caused the device to be created. The uclass is set correctly for
+the device.
+
+The device's bind() method is permitted to perform simple actions, but
+should not scan the device tree node, not initialise hardware, nor set up
+structures or allocate memory. All of these tasks should be left for
+the probe() method.
+
+Note that compared to Linux, U-Boot's driver model has a separate step of
+probe/remove which is independent of bind/unbind. This is partly because in
+U-Boot it may be expensive to prove devices and we don't want to do it until
+they are needed, or perhaps until after relocation.
+
+2. Activation/probe
+
+When a device needs to be used, U-Boot activates it, by following these
+steps (see device_probe()):
+
+   a. If priv_auto_alloc_size is non-zero, then the device-private space
+   is allocated for the device and zeroed. It will be accessible as
+   dev->priv. The driver can put anything it likes in there, but should use
+   it for run-time information, not platform data (which should be static
+   and known before the device is probed).
+
+   b. If platdata_auto_alloc_size is non-zero, then the platform data space
+   is allocated. This is only useful for device tree operation, since
+   otherwise you would have to specific the platform data in the
+   U_BOOT_DEVICE() declaration. The space is allocated for the device and
+   zeroed. It will be accessible as dev->platdata.
+
+   c. If the device's uclass specifies a non-zero per_device_auto_alloc_size,
+   then this space is allocated and zeroed also. It is allocated for and
+   stored in the device, but it is uclass data. owned by the uclass driver.
+   It is possible for the device to access it.
+
+   d. All parent devices are probed. It is not possible to activate a device
+   unless its parents (all the way up to the root device) are activated.
+   This means (for example) that an I2C driver will require that its bus
+   be activated.
+
+   e. If the driver provides a ofdata_to_platdata() method, then this is
+   called to convert the device tree data into platform data. This should
+   do various calls like fdtdec_get_int(gd->fdt_blob, dev->of_offset, ...)
+   to access the node and store the resulting information into dev->platdata.
+   After this point, the device works the same way whether it was bound
+   using a device tree node or U_BOOT_DEVICE() structure. In either case,
+   the platform data is now stored in the platdata structure. Typically you
+   will use the platdata_auto_alloc_size feature to specify the size of the
+   platform data structure, and U-Boot will automatically allocate and zero
+   it for you before entry to ofdata_to_platdata(). But if not, you can
+   allocate it yourself in ofdata_to_platdata(). Note that it is preferable
+   to do all the device tree decoding in ofdata_to_platdata() rather than
+   in probe(). (Apart from the ugliness of mixing configuration and run-time
+   data, one day it is possible that U-Boot will cache platformat data for
+   devices which are regularly de/activated).
+
+   f. The device's probe() method is called. This should do anything that
+   is required by the device to get it going. This could include checking
+   that the hardware is actually present, setting up clocks for the
+   hardware and setting up hardware registers to initial values. The code
+   in probe() can access:
+
+      - platform data in dev->platdata (for configuration)
+      - private data in dev->priv (for run-time state)
+      - uclass data in dev->uclass_priv (for things the uclass stores
+        about this device)
+
+   Note: If you don't use priv_auto_alloc_size then you will need to
+   allocate the priv space here yourself. The same applies also to
+   platdata_auto_alloc_size. Remember to free them in the remove() method.
+
+   g. The device is marked 'activated'
+
+   h. The uclass's post_probe() method is called, if one exists. This may
+   cause the uclass to do some housekeeping to record the device as
+   activated and 'known' by the uclass.
+
+3. Running stage
+
+The device is now activated and can be used. From now until it is removed
+all of the above structures are accessible. The device appears in the
+uclass's list of devices (so if the device is in UCLASS_GPIO it will appear
+as a device in the GPIO uclass). This is the 'running' state of the device.
+
+4. Removal stage
+
+When the device is no-longer required, you can call device_remove() to
+remove it. This performs the probe steps in reverse:
+
+   a. The uclass's pre_remove() method is called, if one exists. This may
+   cause the uclass to do some housekeeping to record the device as
+   deactivated and no-longer 'known' by the uclass.
+
+   b. All the device's children are removed. It is not permitted to have
+   an active child device with a non-active parent. This means that
+   device_remove() is called for all the children recursively at this point.
+
+   c. The device's remove() method is called. At this stage nothing has been
+   deallocated so platform data, private data and the uclass data will all
+   still be present. This is where the hardware can be shut down. It is
+   intended that the device be completely inactive at this point, For U-Boot
+   to be sure that no hardware is running, it should be enough to remove
+   all devices.
+
+   d. The device memory is freed (platform data, private data, uclass data).
+
+   Note: for a U_BOOT_DEVICE() declaration, the platform data is supplied as
+   a static pointer and is not allocated. For device tree, the platform
+   data is allocated during activation and freed during dectivation,
+   typically automatically using platdata_auto_alloc_size. But if that value
+   is 0 then U-Boot will not do the allocation/freeing and you will need to
+   do this yourself in your ofdata_to_platdata() and remove() methods. This
+   difference is tracked by the device's DM_FLAG_ALLOC_PDATA flag.
+
+   e. The device is marked inactive. Note that it is still bound, so the
+   device structure itself is not freed at this point. Should the device be
+   activated again, then the cycle starts again at step 4 above.
+
+5. Unbind stage
+
+The device is unbound. This is the step that actually destroys the device.
+If a parent has children these will be destroyed first. After this point
+the device does not exist and its memory has be deallocated.
+
+
 Data Structures
 ---------------