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authorLinus Torvalds <torvalds@linux-foundation.org>2011-03-16 22:05:40 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-16 22:05:40 -0400
commit63a93699c6a58795b854ff573542a08367684dae (patch)
tree057ab4cbde66862c51867dde030be69a2fa7073f /Documentation
parent16d8775700f1815076f879719ce14b33f50a3171 (diff)
parent21bd6d37cf23e643020bf28b41844ff0040c9393 (diff)
Merge branch 'remove' of master.kernel.org:/home/rmk/linux-2.6-arm
* 'remove' of master.kernel.org:/home/rmk/linux-2.6-arm: ARM: 6629/2: aaec2000: remove support for mach-aaec2000 ARM: lh7a40x: remove unmaintained platform support Fix up trivial conflicts in - arch/arm/mach-{aaec2000,lh7a40x}/include/mach/memory.h (removed) - drivers/usb/gadget/Kconfig (USB_[GADGET_]LH7A40X removed, others added)
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen61
-rw-r--r--Documentation/arm/Sharp-LH/CompactFlash32
-rw-r--r--Documentation/arm/Sharp-LH/IOBarrier45
-rw-r--r--Documentation/arm/Sharp-LH/KEV7A4008
-rw-r--r--Documentation/arm/Sharp-LH/LCDPanels59
-rw-r--r--Documentation/arm/Sharp-LH/LPD7A40015
-rw-r--r--Documentation/arm/Sharp-LH/LPD7A40X16
-rw-r--r--Documentation/arm/Sharp-LH/SDRAM51
-rw-r--r--Documentation/arm/Sharp-LH/VectoredInterruptController80
9 files changed, 0 insertions, 367 deletions
diff --git a/Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen b/Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen
deleted file mode 100644
index dc460f055647..000000000000
--- a/Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen
+++ /dev/null
@@ -1,61 +0,0 @@
1README on the ADC/Touchscreen Controller
2========================================
3
4The LH79524 and LH7A404 include a built-in Analog to Digital
5controller (ADC) that is used to process input from a touchscreen.
6The driver only implements a four-wire touch panel protocol.
7
8The touchscreen driver is maintenance free except for the pen-down or
9touch threshold. Some resistive displays and board combinations may
10require tuning of this threshold. The driver exposes some of its
11internal state in the sys filesystem. If the kernel is configured
12with it, CONFIG_SYSFS, and sysfs is mounted at /sys, there will be a
13directory
14
15 /sys/devices/platform/adc-lh7.0
16
17containing these files.
18
19 -r--r--r-- 1 root root 4096 Jan 1 00:00 samples
20 -rw-r--r-- 1 root root 4096 Jan 1 00:00 threshold
21 -r--r--r-- 1 root root 4096 Jan 1 00:00 threshold_range
22
23The threshold is the current touch threshold. It defaults to 750 on
24most targets.
25
26 # cat threshold
27 750
28
29The threshold_range contains the range of valid values for the
30threshold. Values outside of this range will be silently ignored.
31
32 # cat threshold_range
33 0 1023
34
35To change the threshold, write a value to the threshold file.
36
37 # echo 500 > threshold
38 # cat threshold
39 500
40
41The samples file contains the most recently sampled values from the
42ADC. There are 12. Below are typical of the last sampled values when
43the pen has been released. The first two and last two samples are for
44detecting whether or not the pen is down. The third through sixth are
45X coordinate samples. The seventh through tenth are Y coordinate
46samples.
47
48 # cat samples
49 1023 1023 0 0 0 0 530 529 530 529 1023 1023
50
51To determine a reasonable threshold, press on the touch panel with an
52appropriate stylus and read the values from samples.
53
54 # cat samples
55 1023 676 92 103 101 102 855 919 922 922 1023 679
56
57The first and eleventh samples are discarded. Thus, the important
58values are the second and twelfth which are used to determine if the
59pen is down. When both are below the threshold, the driver registers
60that the pen is down. When either is above the threshold, it
61registers then pen is up.
diff --git a/Documentation/arm/Sharp-LH/CompactFlash b/Documentation/arm/Sharp-LH/CompactFlash
deleted file mode 100644
index 8616d877df9e..000000000000
--- a/Documentation/arm/Sharp-LH/CompactFlash
+++ /dev/null
@@ -1,32 +0,0 @@
1README on the Compact Flash for Card Engines
2============================================
3
4There are three challenges in supporting the CF interface of the Card
5Engines. First, every IO operation must be followed with IO to
6another memory region. Second, the slot is wired for one-to-one
7address mapping *and* it is wired for 16 bit access only. Second, the
8interrupt request line from the CF device isn't wired.
9
10The IOBARRIER issue is covered in README.IOBARRIER. This isn't an
11onerous problem. Enough said here.
12
13The addressing issue is solved in the
14arch/arm/mach-lh7a40x/ide-lpd7a40x.c file with some awkward
15work-arounds. We implement a special SELECT_DRIVE routine that is
16called before the IDE driver performs its own SELECT_DRIVE. Our code
17recognizes that the SELECT register cannot be modified without also
18writing a command. It send an IDLE_IMMEDIATE command on selecting a
19drive. The function also prevents drive select to the slave drive
20since there can be only one. The awkward part is that the IDE driver,
21even though we have a select procedure, also attempts to change the
22drive by writing directly the SELECT register. This attempt is
23explicitly blocked by the OUTB function--not pretty, but effective.
24
25The lack of interrupts is a more serious problem. Even though the CF
26card is fast when compared to a normal IDE device, we don't know that
27the CF is really flash. A user could use one of the very small hard
28drives being shipped with a CF interface. The IDE code includes a
29check for interfaces that lack an IRQ. In these cases, submitting a
30command to the IDE controller is followed by a call to poll for
31completion. If the device isn't immediately ready, it schedules a
32timer to poll again later.
diff --git a/Documentation/arm/Sharp-LH/IOBarrier b/Documentation/arm/Sharp-LH/IOBarrier
deleted file mode 100644
index 2e953e228f4d..000000000000
--- a/Documentation/arm/Sharp-LH/IOBarrier
+++ /dev/null
@@ -1,45 +0,0 @@
1README on the IOBARRIER for CardEngine IO
2=========================================
3
4Due to an unfortunate oversight when the Card Engines were designed,
5the signals that control access to some peripherals, most notably the
6SMC91C9111 ethernet controller, are not properly handled.
7
8The symptom is that some back to back IO with the peripheral returns
9unreliable data. With the SMC chip, you'll see errors about the bank
10register being 'screwed'.
11
12The cause is that the AEN signal to the SMC chip does not transition
13for every memory access. It is driven through the CPLD from the CS7
14line of the CPU's static memory controller which is optimized to
15eliminate unnecessary transitions. Yet, the SMC requires a transition
16for every write access. The Sharp website has more information about
17the effect this power-conserving feature has on peripheral
18interfacing.
19
20The solution is to follow every write access to the SMC chip with an
21access to another memory region that will force the CPU to release the
22chip select line. It is important to guarantee that this access
23forces the CPU off-chip. We map a page of SDRAM as if it were an
24uncacheable IO device and read from it after every SMC IO write
25operation.
26
27 SMC IO
28 BARRIER IO
29
30Only this sequence is important. It does not matter that there is no
31BARRIER IO before the access to the SMC chip because the AEN latch
32only needs occurs after the SMC IO write cycle. The routines that
33implement this work-around make an additional concession which is to
34disable interrupts during the IO sequence. Other hardware devices
35(the LogicPD CPLD) have registers in the same physical memory
36region as the SMC chip. An interrupt might allow an access to one of
37those registers while SMC IO is being performed.
38
39You might be tempted to think that we have to access another device
40attached to the static memory controller, but the empirical evidence
41indicates that this is not so. Mapping 0x00000000 (flash) and
420xc0000000 (SDRAM) appear to have the same effect. Using SDRAM seems
43to be faster. Choosing to access an undecoded memory region is not
44desirable as there is no way to know how that chip select will be used
45in the future.
diff --git a/Documentation/arm/Sharp-LH/KEV7A400 b/Documentation/arm/Sharp-LH/KEV7A400
deleted file mode 100644
index be32b14cd535..000000000000
--- a/Documentation/arm/Sharp-LH/KEV7A400
+++ /dev/null
@@ -1,8 +0,0 @@
1README on Implementing Linux for Sharp's KEV7a400
2=================================================
3
4This product has been discontinued by Sharp. For the time being, the
5partially implemented code remains in the kernel. At some point in
6the future, either the code will be finished or it will be removed
7completely. This depends primarily on how many of the development
8boards are in the field.
diff --git a/Documentation/arm/Sharp-LH/LCDPanels b/Documentation/arm/Sharp-LH/LCDPanels
deleted file mode 100644
index fb1b21c2f2f4..000000000000
--- a/Documentation/arm/Sharp-LH/LCDPanels
+++ /dev/null
@@ -1,59 +0,0 @@
1README on the LCD Panels
2========================
3
4Configuration options for several LCD panels, available from Logic PD,
5are included in the kernel source. This README will help you
6understand the configuration data and give you some guidance for
7adding support for other panels if you wish.
8
9
10lcd-panels.h
11------------
12
13There is no way, at present, to detect which panel is attached to the
14system at runtime. Thus the kernel configuration is static. The file
15arch/arm/mach-ld7a40x/lcd-panels.h (or similar) defines all of the
16panel specific parameters.
17
18It should be possible for this data to be shared among several device
19families. The current layout may be insufficiently general, but it is
20amenable to improvement.
21
22
23PIXEL_CLOCK
24-----------
25
26The panel data sheets will give a range of acceptable pixel clocks.
27The fundamental LCDCLK input frequency is divided down by a PCD
28constant in field '.tim2'. It may happen that it is impossible to set
29the pixel clock within this range. A clock which is too slow will
30tend to flicker. For the highest quality image, set the clock as high
31as possible.
32
33
34MARGINS
35-------
36
37These values may be difficult to glean from the panel data sheet. In
38the case of the Sharp panels, the upper margin is explicitly called
39out as a specific number of lines from the top of the frame. The
40other values may not matter as much as the panels tend to
41automatically center the image.
42
43
44Sync Sense
45----------
46
47The sense of the hsync and vsync pulses may be called out in the data
48sheet. On one panel, the sense of these pulses determine the height
49of the visible region on the panel. Most of the Sharp panels use
50negative sense sync pulses set by the TIM2_IHS and TIM2_IVS bits in
51'.tim2'.
52
53
54Pel Layout
55----------
56
57The Sharp color TFT panels are all configured for 16 bit direct color
58modes. The amba-lcd driver sets the pel mode to 565 for 5 bits of
59each red and blue and 6 bits of green.
diff --git a/Documentation/arm/Sharp-LH/LPD7A400 b/Documentation/arm/Sharp-LH/LPD7A400
deleted file mode 100644
index 3275b453bfdf..000000000000
--- a/Documentation/arm/Sharp-LH/LPD7A400
+++ /dev/null
@@ -1,15 +0,0 @@
1README on Implementing Linux for the Logic PD LPD7A400-10
2=========================================================
3
4- CPLD memory mapping
5
6 The board designers chose to use high address lines for controlling
7 access to the CPLD registers. It turns out to be a big waste
8 because we're using an MMU and must map IO space into virtual
9 memory. The result is that we have to make a mapping for every
10 register.
11
12- Serial Console
13
14 It may be OK not to use the serial console option if the user passes
15 the console device name to the kernel. This deserves some exploration.
diff --git a/Documentation/arm/Sharp-LH/LPD7A40X b/Documentation/arm/Sharp-LH/LPD7A40X
deleted file mode 100644
index 8c29a27e208f..000000000000
--- a/Documentation/arm/Sharp-LH/LPD7A40X
+++ /dev/null
@@ -1,16 +0,0 @@
1README on Implementing Linux for the Logic PD LPD7A40X-10
2=========================================================
3
4- CPLD memory mapping
5
6 The board designers chose to use high address lines for controlling
7 access to the CPLD registers. It turns out to be a big waste
8 because we're using an MMU and must map IO space into virtual
9 memory. The result is that we have to make a mapping for every
10 register.
11
12- Serial Console
13
14 It may be OK not to use the serial console option if the user passes
15 the console device name to the kernel. This deserves some exploration.
16
diff --git a/Documentation/arm/Sharp-LH/SDRAM b/Documentation/arm/Sharp-LH/SDRAM
deleted file mode 100644
index 93ddc23c2faa..000000000000
--- a/Documentation/arm/Sharp-LH/SDRAM
+++ /dev/null
@@ -1,51 +0,0 @@
1README on the SDRAM Controller for the LH7a40X
2==============================================
3
4The standard configuration for the SDRAM controller generates a sparse
5memory array. The precise layout is determined by the SDRAM chips. A
6default kernel configuration assembles the discontiguous memory
7regions into separate memory nodes via the NUMA (Non-Uniform Memory
8Architecture) facilities. In this default configuration, the kernel
9is forgiving about the precise layout. As long as it is given an
10accurate picture of available memory by the bootloader the kernel will
11execute correctly.
12
13The SDRC supports a mode where some of the chip select lines are
14swapped in order to make SDRAM look like a synchronous ROM. Setting
15this bit means that the RAM will present as a contiguous array. Some
16programmers prefer this to the discontiguous layout. Be aware that
17may be a penalty for this feature where some some configurations of
18memory are significantly reduced; i.e. 64MiB of RAM appears as only 32
19MiB.
20
21There are a couple of configuration options to override the default
22behavior. When the SROMLL bit is set and memory appears as a
23contiguous array, there is no reason to support NUMA.
24CONFIG_LH7A40X_CONTIGMEM disables NUMA support. When physical memory
25is discontiguous, the memory tables are organized such that there are
26two banks per nodes with a small gap between them. This layout wastes
27some kernel memory for page tables representing non-existent memory.
28CONFIG_LH7A40X_ONE_BANK_PER_NODE optimizes the node tables such that
29there are no gaps. These options control the low level organization
30of the memory management tables in ways that may prevent the kernel
31from booting or may cause the kernel to allocated excessively large
32page tables. Be warned. Only change these options if you know what
33you are doing. The default behavior is a reasonable compromise that
34will suit all users.
35
36--
37
38A typical 32MiB system with the default configuration options will
39find physical memory managed as follows.
40
41 node 0: 0xc0000000 4MiB
42 0xc1000000 4MiB
43 node 1: 0xc4000000 4MiB
44 0xc5000000 4MiB
45 node 2: 0xc8000000 4MiB
46 0xc9000000 4MiB
47 node 3: 0xcc000000 4MiB
48 0xcd000000 4MiB
49
50Setting CONFIG_LH7A40X_ONE_BANK_PER_NODE will put each bank into a
51separate node.
diff --git a/Documentation/arm/Sharp-LH/VectoredInterruptController b/Documentation/arm/Sharp-LH/VectoredInterruptController
deleted file mode 100644
index 23047e9861ee..000000000000
--- a/Documentation/arm/Sharp-LH/VectoredInterruptController
+++ /dev/null
@@ -1,80 +0,0 @@
1README on the Vectored Interrupt Controller of the LH7A404
2==========================================================
3
4The 404 revision of the LH7A40X series comes with two vectored
5interrupts controllers. While the kernel does use some of the
6features of these devices, it is far from the purpose for which they
7were designed.
8
9When this README was written, the implementation of the VICs was in
10flux. It is possible that some details, especially with priorities,
11will change.
12
13The VIC support code is inspired by routines written by Sharp.
14
15
16Priority Control
17----------------
18
19The significant reason for using the VIC's vectoring is to control
20interrupt priorities. There are two tables in
21arch/arm/mach-lh7a40x/irq-lh7a404.c that look something like this.
22
23 static unsigned char irq_pri_vic1[] = { IRQ_GPIO3INTR, };
24 static unsigned char irq_pri_vic2[] = {
25 IRQ_T3UI, IRQ_GPIO7INTR,
26 IRQ_UART1INTR, IRQ_UART2INTR, IRQ_UART3INTR, };
27
28The initialization code reads these tables and inserts a vector
29address and enable for each indicated IRQ. Vectored interrupts have
30higher priority than non-vectored interrupts. So, on VIC1,
31IRQ_GPIO3INTR will be served before any other non-FIQ interrupt. Due
32to the way that the vectoring works, IRQ_T3UI is the next highest
33priority followed by the other vectored interrupts on VIC2. After
34that, the non-vectored interrupts are scanned in VIC1 then in VIC2.
35
36
37ISR
38---
39
40The interrupt service routine macro get_irqnr() in
41arch/arm/kernel/entry-armv.S scans the VICs for the next active
42interrupt. The vectoring makes this code somewhat larger than it was
43before using vectoring (refer to the LH7A400 implementation). In the
44case where an interrupt is vectored, the implementation will tend to
45be faster than the non-vectored version. However, the worst-case path
46is longer.
47
48It is worth noting that at present, there is no need to read
49VIC2_VECTADDR because the register appears to be shared between the
50controllers. The code is written such that if this changes, it ought
51to still work properly.
52
53
54Vector Addresses
55----------------
56
57The proper use of the vectoring hardware would jump to the ISR
58specified by the vectoring address. Linux isn't structured to take
59advantage of this feature, though it might be possible to change
60things to support it.
61
62In this implementation, the vectoring address is used to speed the
63search for the active IRQ. The address is coded such that the lowest
646 bits store the IRQ number for vectored interrupts. These numbers
65correspond to the bits in the interrupt status registers. IRQ zero is
66the lowest interrupt bit in VIC1. IRQ 32 is the lowest interrupt bit
67in VIC2. Because zero is a valid IRQ number and because we cannot
68detect whether or not there is a valid vectoring address if that
69address is zero, the eigth bit (0x100) is set for vectored interrupts.
70The address for IRQ 0x18 (VIC2) is 0x118. Only the ninth bit is set
71for the default handler on VIC1 and only the tenth bit is set for the
72default handler on VIC2.
73
74In other words.
75
76 0x000 - no active interrupt
77 0x1ii - vectored interrupt 0xii
78 0x2xx - unvectored interrupt on VIC1 (xx is don't care)
79 0x4xx - unvectored interrupt on VIC2 (xx is don't care)
80