diff options
Diffstat (limited to '')
| -rw-r--r-- | Documentation/arm/IXP4xx | 4 | ||||
| -rw-r--r-- | Documentation/arm/SH-Mobile/Makefile | 8 | ||||
| -rw-r--r-- | Documentation/arm/SH-Mobile/vrl4.c | 169 | ||||
| -rw-r--r-- | Documentation/arm/SH-Mobile/zboot-rom-mmcif.txt | 29 | ||||
| -rw-r--r-- | Documentation/arm/Samsung-S3C24XX/Suspend.txt | 2 | ||||
| -rw-r--r-- | Documentation/arm/Samsung/GPIO.txt | 2 | ||||
| -rw-r--r-- | Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen | 61 | ||||
| -rw-r--r-- | Documentation/arm/Sharp-LH/CompactFlash | 32 | ||||
| -rw-r--r-- | Documentation/arm/Sharp-LH/IOBarrier | 45 | ||||
| -rw-r--r-- | Documentation/arm/Sharp-LH/KEV7A400 | 8 | ||||
| -rw-r--r-- | Documentation/arm/Sharp-LH/LCDPanels | 59 | ||||
| -rw-r--r-- | Documentation/arm/Sharp-LH/LPD7A400 | 15 | ||||
| -rw-r--r-- | Documentation/arm/Sharp-LH/LPD7A40X | 16 | ||||
| -rw-r--r-- | Documentation/arm/Sharp-LH/SDRAM | 51 | ||||
| -rw-r--r-- | Documentation/arm/Sharp-LH/VectoredInterruptController | 80 |
15 files changed, 210 insertions, 371 deletions
diff --git a/Documentation/arm/IXP4xx b/Documentation/arm/IXP4xx index 133c5fa6c7a1..7b9351f2f555 100644 --- a/Documentation/arm/IXP4xx +++ b/Documentation/arm/IXP4xx @@ -36,7 +36,7 @@ Linux currently supports the following features on the IXP4xx chips: - Timers (watchdog, OS) The following components of the chips are not supported by Linux and -require the use of Intel's propietary CSR softare: +require the use of Intel's proprietary CSR softare: - USB device interface - Network interfaces (HSS, Utopia, NPEs, etc) @@ -47,7 +47,7 @@ software from: http://developer.intel.com/design/network/products/npfamily/ixp425.htm -DO NOT POST QUESTIONS TO THE LINUX MAILING LISTS REGARDING THE PROPIETARY +DO NOT POST QUESTIONS TO THE LINUX MAILING LISTS REGARDING THE PROPRIETARY SOFTWARE. There are several websites that provide directions/pointers on using diff --git a/Documentation/arm/SH-Mobile/Makefile b/Documentation/arm/SH-Mobile/Makefile new file mode 100644 index 000000000000..8771d832cf8c --- /dev/null +++ b/Documentation/arm/SH-Mobile/Makefile @@ -0,0 +1,8 @@ +BIN := vrl4 + +.PHONY: all +all: $(BIN) + +.PHONY: clean +clean: + rm -f *.o $(BIN) diff --git a/Documentation/arm/SH-Mobile/vrl4.c b/Documentation/arm/SH-Mobile/vrl4.c new file mode 100644 index 000000000000..e8a191358ad2 --- /dev/null +++ b/Documentation/arm/SH-Mobile/vrl4.c @@ -0,0 +1,169 @@ +/* + * vrl4 format generator + * + * Copyright (C) 2010 Simon Horman + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +/* + * usage: vrl4 < zImage > out + * dd if=out of=/dev/sdx bs=512 seek=1 # Write the image to sector 1 + * + * Reads a zImage from stdin and writes a vrl4 image to stdout. + * In practice this means writing a padded vrl4 header to stdout followed + * by the zImage. + * + * The padding places the zImage at ALIGN bytes into the output. + * The vrl4 uses ALIGN + START_BASE as the start_address. + * This is where the mask ROM will jump to after verifying the header. + * + * The header sets copy_size to min(sizeof(zImage), MAX_BOOT_PROG_LEN) + ALIGN. + * That is, the mask ROM will load the padded header (ALIGN bytes) + * And then MAX_BOOT_PROG_LEN bytes of the image, or the entire image, + * whichever is smaller. + * + * The zImage is not modified in any way. + */ + +#define _BSD_SOURCE +#include <endian.h> +#include <unistd.h> +#include <stdint.h> +#include <stdio.h> +#include <errno.h> + +struct hdr { + uint32_t magic1; + uint32_t reserved1; + uint32_t magic2; + uint32_t reserved2; + uint16_t copy_size; + uint16_t boot_options; + uint32_t reserved3; + uint32_t start_address; + uint32_t reserved4; + uint32_t reserved5; + char reserved6[308]; +}; + +#define DECLARE_HDR(h) \ + struct hdr (h) = { \ + .magic1 = htole32(0xea000000), \ + .reserved1 = htole32(0x56), \ + .magic2 = htole32(0xe59ff008), \ + .reserved3 = htole16(0x1) } + +/* Align to 512 bytes, the MMCIF sector size */ +#define ALIGN_BITS 9 +#define ALIGN (1 << ALIGN_BITS) + +#define START_BASE 0xe55b0000 + +/* + * With an alignment of 512 the header uses the first sector. + * There is a 128 sector (64kbyte) limit on the data loaded by the mask ROM. + * So there are 127 sectors left for the boot programme. But in practice + * Only a small portion of a zImage is needed, 16 sectors should be more + * than enough. + * + * Note that this sets how much of the zImage is copied by the mask ROM. + * The entire zImage is present after the header and is loaded + * by the code in the boot program (which is the first portion of the zImage). + */ +#define MAX_BOOT_PROG_LEN (16 * 512) + +#define ROUND_UP(x) ((x + ALIGN - 1) & ~(ALIGN - 1)) + +ssize_t do_read(int fd, void *buf, size_t count) +{ + size_t offset = 0; + ssize_t l; + + while (offset < count) { + l = read(fd, buf + offset, count - offset); + if (!l) + break; + if (l < 0) { + if (errno == EAGAIN || errno == EWOULDBLOCK) + continue; + perror("read"); + return -1; + } + offset += l; + } + + return offset; +} + +ssize_t do_write(int fd, const void *buf, size_t count) +{ + size_t offset = 0; + ssize_t l; + + while (offset < count) { + l = write(fd, buf + offset, count - offset); + if (l < 0) { + if (errno == EAGAIN || errno == EWOULDBLOCK) + continue; + perror("write"); + return -1; + } + offset += l; + } + + return offset; +} + +ssize_t write_zero(int fd, size_t len) +{ + size_t i = len; + + while (i--) { + const char x = 0; + if (do_write(fd, &x, 1) < 0) + return -1; + } + + return len; +} + +int main(void) +{ + DECLARE_HDR(hdr); + char boot_program[MAX_BOOT_PROG_LEN]; + size_t aligned_hdr_len, alligned_prog_len; + ssize_t prog_len; + + prog_len = do_read(0, boot_program, sizeof(boot_program)); + if (prog_len <= 0) + return -1; + + aligned_hdr_len = ROUND_UP(sizeof(hdr)); + hdr.start_address = htole32(START_BASE + aligned_hdr_len); + alligned_prog_len = ROUND_UP(prog_len); + hdr.copy_size = htole16(aligned_hdr_len + alligned_prog_len); + + if (do_write(1, &hdr, sizeof(hdr)) < 0) + return -1; + if (write_zero(1, aligned_hdr_len - sizeof(hdr)) < 0) + return -1; + + if (do_write(1, boot_program, prog_len) < 0) + return 1; + + /* Write out the rest of the kernel */ + while (1) { + prog_len = do_read(0, boot_program, sizeof(boot_program)); + if (prog_len < 0) + return 1; + if (prog_len == 0) + break; + if (do_write(1, boot_program, prog_len) < 0) + return 1; + } + + return 0; +} diff --git a/Documentation/arm/SH-Mobile/zboot-rom-mmcif.txt b/Documentation/arm/SH-Mobile/zboot-rom-mmcif.txt new file mode 100644 index 000000000000..efff8ae2713d --- /dev/null +++ b/Documentation/arm/SH-Mobile/zboot-rom-mmcif.txt @@ -0,0 +1,29 @@ +ROM-able zImage boot from MMC +----------------------------- + +An ROM-able zImage compiled with ZBOOT_ROM_MMCIF may be written to MMC and +SuperH Mobile ARM will to boot directly from the MMCIF hardware block. + +This is achieved by the mask ROM loading the first portion of the image into +MERAM and then jumping to it. This portion contains loader code which +copies the entire image to SDRAM and jumps to it. From there the zImage +boot code proceeds as normal, uncompressing the image into its final +location and then jumping to it. + +This code has been tested on an AP4EB board using the developer 1A eMMC +boot mode which is configured using the following jumper settings. +The board used for testing required a patched mask ROM in order for +this mode to function. + + 8 7 6 5 4 3 2 1 + x|x|x|x|x| |x| +S4 -+-+-+-+-+-+-+- + | | | | |x| |x on + +The zImage must be written to the MMC card at sector 1 (512 bytes) in +vrl4 format. A utility vrl4 is supplied to accomplish this. + +e.g. + vrl4 < zImage | dd of=/dev/sdX bs=512 seek=1 + +A dual-voltage MMC 4.0 card was used for testing. diff --git a/Documentation/arm/Samsung-S3C24XX/Suspend.txt b/Documentation/arm/Samsung-S3C24XX/Suspend.txt index 7edd0e2e6c5b..1ca63b3e5635 100644 --- a/Documentation/arm/Samsung-S3C24XX/Suspend.txt +++ b/Documentation/arm/Samsung-S3C24XX/Suspend.txt @@ -116,7 +116,7 @@ Configuration Allows the entire memory to be checksummed before and after the suspend to see if there has been any corruption of the contents. - Note, the time to calculate the CRC is dependant on the CPU speed + Note, the time to calculate the CRC is dependent on the CPU speed and the size of memory. For an 64Mbyte RAM area on an 200MHz S3C2410, this can take approximately 4 seconds to complete. diff --git a/Documentation/arm/Samsung/GPIO.txt b/Documentation/arm/Samsung/GPIO.txt index 05850c62abeb..513f2562c1a3 100644 --- a/Documentation/arm/Samsung/GPIO.txt +++ b/Documentation/arm/Samsung/GPIO.txt @@ -5,7 +5,7 @@ Introduction ------------ This outlines the Samsung GPIO implementation and the architecture -specfic calls provided alongisde the drivers/gpio core. +specific calls provided alongisde the drivers/gpio core. S3C24XX (Legacy) 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 @@ -README on the ADC/Touchscreen Controller -======================================== - -The LH79524 and LH7A404 include a built-in Analog to Digital -controller (ADC) that is used to process input from a touchscreen. -The driver only implements a four-wire touch panel protocol. - -The touchscreen driver is maintenance free except for the pen-down or -touch threshold. Some resistive displays and board combinations may -require tuning of this threshold. The driver exposes some of its -internal state in the sys filesystem. If the kernel is configured -with it, CONFIG_SYSFS, and sysfs is mounted at /sys, there will be a -directory - - /sys/devices/platform/adc-lh7.0 - -containing these files. - - -r--r--r-- 1 root root 4096 Jan 1 00:00 samples - -rw-r--r-- 1 root root 4096 Jan 1 00:00 threshold - -r--r--r-- 1 root root 4096 Jan 1 00:00 threshold_range - -The threshold is the current touch threshold. It defaults to 750 on -most targets. - - # cat threshold - 750 - -The threshold_range contains the range of valid values for the -threshold. Values outside of this range will be silently ignored. - - # cat threshold_range - 0 1023 - -To change the threshold, write a value to the threshold file. - - # echo 500 > threshold - # cat threshold - 500 - -The samples file contains the most recently sampled values from the -ADC. There are 12. Below are typical of the last sampled values when -the pen has been released. The first two and last two samples are for -detecting whether or not the pen is down. The third through sixth are -X coordinate samples. The seventh through tenth are Y coordinate -samples. - - # cat samples - 1023 1023 0 0 0 0 530 529 530 529 1023 1023 - -To determine a reasonable threshold, press on the touch panel with an -appropriate stylus and read the values from samples. - - # cat samples - 1023 676 92 103 101 102 855 919 922 922 1023 679 - -The first and eleventh samples are discarded. Thus, the important -values are the second and twelfth which are used to determine if the -pen is down. When both are below the threshold, the driver registers -that the pen is down. When either is above the threshold, it -registers 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 @@ -README on the Compact Flash for Card Engines -============================================ - -There are three challenges in supporting the CF interface of the Card -Engines. First, every IO operation must be followed with IO to -another memory region. Second, the slot is wired for one-to-one -address mapping *and* it is wired for 16 bit access only. Second, the -interrupt request line from the CF device isn't wired. - -The IOBARRIER issue is covered in README.IOBARRIER. This isn't an -onerous problem. Enough said here. - -The addressing issue is solved in the -arch/arm/mach-lh7a40x/ide-lpd7a40x.c file with some awkward -work-arounds. We implement a special SELECT_DRIVE routine that is -called before the IDE driver performs its own SELECT_DRIVE. Our code -recognizes that the SELECT register cannot be modified without also -writing a command. It send an IDLE_IMMEDIATE command on selecting a -drive. The function also prevents drive select to the slave drive -since there can be only one. The awkward part is that the IDE driver, -even though we have a select procedure, also attempts to change the -drive by writing directly the SELECT register. This attempt is -explicitly blocked by the OUTB function--not pretty, but effective. - -The lack of interrupts is a more serious problem. Even though the CF -card is fast when compared to a normal IDE device, we don't know that -the CF is really flash. A user could use one of the very small hard -drives being shipped with a CF interface. The IDE code includes a -check for interfaces that lack an IRQ. In these cases, submitting a -command to the IDE controller is followed by a call to poll for -completion. If the device isn't immediately ready, it schedules a -timer 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 @@ -README on the IOBARRIER for CardEngine IO -========================================= - -Due to an unfortunate oversight when the Card Engines were designed, -the signals that control access to some peripherals, most notably the -SMC91C9111 ethernet controller, are not properly handled. - -The symptom is that some back to back IO with the peripheral returns -unreliable data. With the SMC chip, you'll see errors about the bank -register being 'screwed'. - -The cause is that the AEN signal to the SMC chip does not transition -for every memory access. It is driven through the CPLD from the CS7 -line of the CPU's static memory controller which is optimized to -eliminate unnecessary transitions. Yet, the SMC requires a transition -for every write access. The Sharp website has more information about -the effect this power-conserving feature has on peripheral -interfacing. - -The solution is to follow every write access to the SMC chip with an -access to another memory region that will force the CPU to release the -chip select line. It is important to guarantee that this access -forces the CPU off-chip. We map a page of SDRAM as if it were an -uncacheable IO device and read from it after every SMC IO write -operation. - - SMC IO - BARRIER IO - -Only this sequence is important. It does not matter that there is no -BARRIER IO before the access to the SMC chip because the AEN latch -only needs occurs after the SMC IO write cycle. The routines that -implement this work-around make an additional concession which is to -disable interrupts during the IO sequence. Other hardware devices -(the LogicPD CPLD) have registers in the same physical memory -region as the SMC chip. An interrupt might allow an access to one of -those registers while SMC IO is being performed. - -You might be tempted to think that we have to access another device -attached to the static memory controller, but the empirical evidence -indicates that this is not so. Mapping 0x00000000 (flash) and -0xc0000000 (SDRAM) appear to have the same effect. Using SDRAM seems -to be faster. Choosing to access an undecoded memory region is not -desirable as there is no way to know how that chip select will be used -in 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 @@ -README on Implementing Linux for Sharp's KEV7a400 -================================================= - -This product has been discontinued by Sharp. For the time being, the -partially implemented code remains in the kernel. At some point in -the future, either the code will be finished or it will be removed -completely. This depends primarily on how many of the development -boards 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 @@ -README on the LCD Panels -======================== - -Configuration options for several LCD panels, available from Logic PD, -are included in the kernel source. This README will help you -understand the configuration data and give you some guidance for -adding support for other panels if you wish. - - -lcd-panels.h ------------- - -There is no way, at present, to detect which panel is attached to the -system at runtime. Thus the kernel configuration is static. The file -arch/arm/mach-ld7a40x/lcd-panels.h (or similar) defines all of the -panel specific parameters. - -It should be possible for this data to be shared among several device -families. The current layout may be insufficiently general, but it is -amenable to improvement. - - -PIXEL_CLOCK ------------ - -The panel data sheets will give a range of acceptable pixel clocks. -The fundamental LCDCLK input frequency is divided down by a PCD -constant in field '.tim2'. It may happen that it is impossible to set -the pixel clock within this range. A clock which is too slow will -tend to flicker. For the highest quality image, set the clock as high -as possible. - - -MARGINS -------- - -These values may be difficult to glean from the panel data sheet. In -the case of the Sharp panels, the upper margin is explicitly called -out as a specific number of lines from the top of the frame. The -other values may not matter as much as the panels tend to -automatically center the image. - - -Sync Sense ----------- - -The sense of the hsync and vsync pulses may be called out in the data -sheet. On one panel, the sense of these pulses determine the height -of the visible region on the panel. Most of the Sharp panels use -negative sense sync pulses set by the TIM2_IHS and TIM2_IVS bits in -'.tim2'. - - -Pel Layout ----------- - -The Sharp color TFT panels are all configured for 16 bit direct color -modes. The amba-lcd driver sets the pel mode to 565 for 5 bits of -each 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 @@ -README on Implementing Linux for the Logic PD LPD7A400-10 -========================================================= - -- CPLD memory mapping - - The board designers chose to use high address lines for controlling - access to the CPLD registers. It turns out to be a big waste - because we're using an MMU and must map IO space into virtual - memory. The result is that we have to make a mapping for every - register. - -- Serial Console - - It may be OK not to use the serial console option if the user passes - 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 @@ -README on Implementing Linux for the Logic PD LPD7A40X-10 -========================================================= - -- CPLD memory mapping - - The board designers chose to use high address lines for controlling - access to the CPLD registers. It turns out to be a big waste - because we're using an MMU and must map IO space into virtual - memory. The result is that we have to make a mapping for every - register. - -- Serial Console - - It may be OK not to use the serial console option if the user passes - the console device name to the kernel. This deserves some exploration. - 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 @@ -README on the SDRAM Controller for the LH7a40X -============================================== - -The standard configuration for the SDRAM controller generates a sparse -memory array. The precise layout is determined by the SDRAM chips. A -default kernel configuration assembles the discontiguous memory -regions into separate memory nodes via the NUMA (Non-Uniform Memory -Architecture) facilities. In this default configuration, the kernel -is forgiving about the precise layout. As long as it is given an -accurate picture of available memory by the bootloader the kernel will -execute correctly. - -The SDRC supports a mode where some of the chip select lines are -swapped in order to make SDRAM look like a synchronous ROM. Setting -this bit means that the RAM will present as a contiguous array. Some -programmers prefer this to the discontiguous layout. Be aware that -may be a penalty for this feature where some some configurations of -memory are significantly reduced; i.e. 64MiB of RAM appears as only 32 -MiB. - -There are a couple of configuration options to override the default -behavior. When the SROMLL bit is set and memory appears as a -contiguous array, there is no reason to support NUMA. -CONFIG_LH7A40X_CONTIGMEM disables NUMA support. When physical memory -is discontiguous, the memory tables are organized such that there are -two banks per nodes with a small gap between them. This layout wastes -some kernel memory for page tables representing non-existent memory. -CONFIG_LH7A40X_ONE_BANK_PER_NODE optimizes the node tables such that -there are no gaps. These options control the low level organization -of the memory management tables in ways that may prevent the kernel -from booting or may cause the kernel to allocated excessively large -page tables. Be warned. Only change these options if you know what -you are doing. The default behavior is a reasonable compromise that -will suit all users. - --- - -A typical 32MiB system with the default configuration options will -find physical memory managed as follows. - - node 0: 0xc0000000 4MiB - 0xc1000000 4MiB - node 1: 0xc4000000 4MiB - 0xc5000000 4MiB - node 2: 0xc8000000 4MiB - 0xc9000000 4MiB - node 3: 0xcc000000 4MiB - 0xcd000000 4MiB - -Setting CONFIG_LH7A40X_ONE_BANK_PER_NODE will put each bank into a -separate 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 @@ -README on the Vectored Interrupt Controller of the LH7A404 -========================================================== - -The 404 revision of the LH7A40X series comes with two vectored -interrupts controllers. While the kernel does use some of the -features of these devices, it is far from the purpose for which they -were designed. - -When this README was written, the implementation of the VICs was in -flux. It is possible that some details, especially with priorities, -will change. - -The VIC support code is inspired by routines written by Sharp. - - -Priority Control ----------------- - -The significant reason for using the VIC's vectoring is to control -interrupt priorities. There are two tables in -arch/arm/mach-lh7a40x/irq-lh7a404.c that look something like this. - - static unsigned char irq_pri_vic1[] = { IRQ_GPIO3INTR, }; - static unsigned char irq_pri_vic2[] = { - IRQ_T3UI, IRQ_GPIO7INTR, - IRQ_UART1INTR, IRQ_UART2INTR, IRQ_UART3INTR, }; - -The initialization code reads these tables and inserts a vector -address and enable for each indicated IRQ. Vectored interrupts have -higher priority than non-vectored interrupts. So, on VIC1, -IRQ_GPIO3INTR will be served before any other non-FIQ interrupt. Due -to the way that the vectoring works, IRQ_T3UI is the next highest -priority followed by the other vectored interrupts on VIC2. After -that, the non-vectored interrupts are scanned in VIC1 then in VIC2. - - -ISR ---- - -The interrupt service routine macro get_irqnr() in -arch/arm/kernel/entry-armv.S scans the VICs for the next active -interrupt. The vectoring makes this code somewhat larger than it was -before using vectoring (refer to the LH7A400 implementation). In the -case where an interrupt is vectored, the implementation will tend to -be faster than the non-vectored version. However, the worst-case path -is longer. - -It is worth noting that at present, there is no need to read -VIC2_VECTADDR because the register appears to be shared between the -controllers. The code is written such that if this changes, it ought -to still work properly. - - -Vector Addresses ----------------- - -The proper use of the vectoring hardware would jump to the ISR -specified by the vectoring address. Linux isn't structured to take -advantage of this feature, though it might be possible to change -things to support it. - -In this implementation, the vectoring address is used to speed the -search for the active IRQ. The address is coded such that the lowest -6 bits store the IRQ number for vectored interrupts. These numbers -correspond to the bits in the interrupt status registers. IRQ zero is -the lowest interrupt bit in VIC1. IRQ 32 is the lowest interrupt bit -in VIC2. Because zero is a valid IRQ number and because we cannot -detect whether or not there is a valid vectoring address if that -address is zero, the eigth bit (0x100) is set for vectored interrupts. -The address for IRQ 0x18 (VIC2) is 0x118. Only the ninth bit is set -for the default handler on VIC1 and only the tenth bit is set for the -default handler on VIC2. - -In other words. - - 0x000 - no active interrupt - 0x1ii - vectored interrupt 0xii - 0x2xx - unvectored interrupt on VIC1 (xx is don't care) - 0x4xx - unvectored interrupt on VIC2 (xx is don't care) - |