diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-mmc | 21 | ||||
| -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/cpu-freq/governors.txt | 11 | ||||
| -rw-r--r-- | Documentation/hwmon/twl4030-madc-hwmon | 45 | ||||
| -rw-r--r-- | Documentation/hwspinlock.txt | 293 | ||||
| -rw-r--r-- | Documentation/usb/usbmon.txt | 42 |
8 files changed, 585 insertions, 33 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-mmc b/Documentation/ABI/testing/sysfs-devices-mmc new file mode 100644 index 00000000000..5a50ab65584 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-mmc @@ -0,0 +1,21 @@ +What: /sys/devices/.../mmc_host/mmcX/mmcX:XXXX/enhanced_area_offset +Date: January 2011 +Contact: Chuanxiao Dong <chuanxiao.dong@intel.com> +Description: + Enhanced area is a new feature defined in eMMC4.4 standard. + eMMC4.4 or later card can support such feature. This kind of + area can help to improve the card performance. If the feature + is enabled, this attribute will indicate the start address of + enhanced data area. If not, this attribute will be -EINVAL. + Unit Byte. Format decimal. + +What: /sys/devices/.../mmc_host/mmcX/mmcX:XXXX/enhanced_area_size +Date: January 2011 +Contact: Chuanxiao Dong <chuanxiao.dong@intel.com> +Description: + Enhanced area is a new feature defined in eMMC4.4 standard. + eMMC4.4 or later card can support such feature. This kind of + area can help to improve the card performance. If the feature + is enabled, this attribute will indicate the size of enhanced + data area. If not, this attribute will be -EINVAL. + Unit KByte. Format decimal. diff --git a/Documentation/arm/SH-Mobile/Makefile b/Documentation/arm/SH-Mobile/Makefile new file mode 100644 index 00000000000..8771d832cf8 --- /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 00000000000..e8a191358ad --- /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 00000000000..efff8ae2713 --- /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/cpu-freq/governors.txt b/Documentation/cpu-freq/governors.txt index 737988fca64..e74d0a2eb1c 100644 --- a/Documentation/cpu-freq/governors.txt +++ b/Documentation/cpu-freq/governors.txt @@ -158,6 +158,17 @@ intensive calculation on your laptop that you do not care how long it takes to complete as you can 'nice' it and prevent it from taking part in the deciding process of whether to increase your CPU frequency. +sampling_down_factor: this parameter controls the rate at which the +kernel makes a decision on when to decrease the frequency while running +at top speed. When set to 1 (the default) decisions to reevaluate load +are made at the same interval regardless of current clock speed. But +when set to greater than 1 (e.g. 100) it acts as a multiplier for the +scheduling interval for reevaluating load when the CPU is at its top +speed due to high load. This improves performance by reducing the overhead +of load evaluation and helping the CPU stay at its top speed when truly +busy, rather than shifting back and forth in speed. This tunable has no +effect on behavior at lower speeds/lower CPU loads. + 2.5 Conservative ---------------- diff --git a/Documentation/hwmon/twl4030-madc-hwmon b/Documentation/hwmon/twl4030-madc-hwmon new file mode 100644 index 00000000000..ef7984317ce --- /dev/null +++ b/Documentation/hwmon/twl4030-madc-hwmon @@ -0,0 +1,45 @@ +Kernel driver twl4030-madc +========================= + +Supported chips: + * Texas Instruments TWL4030 + Prefix: 'twl4030-madc' + + +Authors: + J Keerthy <j-keerthy@ti.com> + +Description +----------- + +The Texas Instruments TWL4030 is a Power Management and Audio Circuit. Among +other things it contains a 10-bit A/D converter MADC. The converter has 16 +channels which can be used in different modes. + + +See this table for the meaning of the different channels + +Channel Signal +------------------------------------------ +0 Battery type(BTYPE) +1 BCI: Battery temperature (BTEMP) +2 GP analog input +3 GP analog input +4 GP analog input +5 GP analog input +6 GP analog input +7 GP analog input +8 BCI: VBUS voltage(VBUS) +9 Backup Battery voltage (VBKP) +10 BCI: Battery charger current (ICHG) +11 BCI: Battery charger voltage (VCHG) +12 BCI: Main battery voltage (VBAT) +13 Reserved +14 Reserved +15 VRUSB Supply/Speaker left/Speaker right polarization level + + +The Sysfs nodes will represent the voltage in the units of mV, +the temperature channel shows the converted temperature in +degree celcius. The Battery charging current channel represents +battery charging current in mA. diff --git a/Documentation/hwspinlock.txt b/Documentation/hwspinlock.txt new file mode 100644 index 00000000000..7dcd1a4e726 --- /dev/null +++ b/Documentation/hwspinlock.txt @@ -0,0 +1,293 @@ +Hardware Spinlock Framework + +1. Introduction + +Hardware spinlock modules provide hardware assistance for synchronization +and mutual exclusion between heterogeneous processors and those not operating +under a single, shared operating system. + +For example, OMAP4 has dual Cortex-A9, dual Cortex-M3 and a C64x+ DSP, +each of which is running a different Operating System (the master, A9, +is usually running Linux and the slave processors, the M3 and the DSP, +are running some flavor of RTOS). + +A generic hwspinlock framework allows platform-independent drivers to use +the hwspinlock device in order to access data structures that are shared +between remote processors, that otherwise have no alternative mechanism +to accomplish synchronization and mutual exclusion operations. + +This is necessary, for example, for Inter-processor communications: +on OMAP4, cpu-intensive multimedia tasks are offloaded by the host to the +remote M3 and/or C64x+ slave processors (by an IPC subsystem called Syslink). + +To achieve fast message-based communications, a minimal kernel support +is needed to deliver messages arriving from a remote processor to the +appropriate user process. + +This communication is based on simple data structures that is shared between +the remote processors, and access to it is synchronized using the hwspinlock +module (remote processor directly places new messages in this shared data +structure). + +A common hwspinlock interface makes it possible to have generic, platform- +independent, drivers. + +2. User API + + struct hwspinlock *hwspin_lock_request(void); + - dynamically assign an hwspinlock and return its address, or NULL + in case an unused hwspinlock isn't available. Users of this + API will usually want to communicate the lock's id to the remote core + before it can be used to achieve synchronization. + Can be called from an atomic context (this function will not sleep) but + not from within interrupt context. + + struct hwspinlock *hwspin_lock_request_specific(unsigned int id); + - assign a specific hwspinlock id and return its address, or NULL + if that hwspinlock is already in use. Usually board code will + be calling this function in order to reserve specific hwspinlock + ids for predefined purposes. + Can be called from an atomic context (this function will not sleep) but + not from within interrupt context. + + int hwspin_lock_free(struct hwspinlock *hwlock); + - free a previously-assigned hwspinlock; returns 0 on success, or an + appropriate error code on failure (e.g. -EINVAL if the hwspinlock + is already free). + Can be called from an atomic context (this function will not sleep) but + not from within interrupt context. + + int hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int timeout); + - lock a previously-assigned hwspinlock with a timeout limit (specified in + msecs). If the hwspinlock is already taken, the function will busy loop + waiting for it to be released, but give up when the timeout elapses. + Upon a successful return from this function, preemption is disabled so + the caller must not sleep, and is advised to release the hwspinlock as + soon as possible, in order to minimize remote cores polling on the + hardware interconnect. + Returns 0 when successful and an appropriate error code otherwise (most + notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs). + The function will never sleep. + + int hwspin_lock_timeout_irq(struct hwspinlock *hwlock, unsigned int timeout); + - lock a previously-assigned hwspinlock with a timeout limit (specified in + msecs). If the hwspinlock is already taken, the function will busy loop + waiting for it to be released, but give up when the timeout elapses. + Upon a successful return from this function, preemption and the local + interrupts are disabled, so the caller must not sleep, and is advised to + release the hwspinlock as soon as possible. + Returns 0 when successful and an appropriate error code otherwise (most + notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs). + The function will never sleep. + + int hwspin_lock_timeout_irqsave(struct hwspinlock *hwlock, unsigned int to, + unsigned long *flags); + - lock a previously-assigned hwspinlock with a timeout limit (specified in + msecs). If the hwspinlock is already taken, the function will busy loop + waiting for it to be released, but give up when the timeout elapses. + Upon a successful return from this function, preemption is disabled, + local interrupts are disabled and their previous state is saved at the + given flags placeholder. The caller must not sleep, and is advised to + release the hwspinlock as soon as possible. + Returns 0 when successful and an appropriate error code otherwise (most + notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs). + The function will never sleep. + + int hwspin_trylock(struct hwspinlock *hwlock); + - attempt to lock a previously-assigned hwspinlock, but immediately fail if + it is already taken. + Upon a successful return from this function, preemption is disabled so + caller must not sleep, and is advised to release the hwspinlock as soon as + possible, in order to minimize remote cores polling on the hardware + interconnect. + Returns 0 on success and an appropriate error code otherwise (most + notably -EBUSY if the hwspinlock was already taken). + The function will never sleep. + + int hwspin_trylock_irq(struct hwspinlock *hwlock); + - attempt to lock a previously-assigned hwspinlock, but immediately fail if + it is already taken. + Upon a successful return from this function, preemption and the local + interrupts are disabled so caller must not sleep, and is advised to + release the hwspinlock as soon as possible. + Returns 0 on success and an appropriate error code otherwise (most + notably -EBUSY if the hwspinlock was already taken). + The function will never sleep. + + int hwspin_trylock_irqsave(struct hwspinlock *hwlock, unsigned long *flags); + - attempt to lock a previously-assigned hwspinlock, but immediately fail if + it is already taken. + Upon a successful return from this function, preemption is disabled, + the local interrupts are disabled and their previous state is saved + at the given flags placeholder. The caller must not sleep, and is advised + to release the hwspinlock as soon as possible. + Returns 0 on success and an appropriate error code otherwise (most + notably -EBUSY if the hwspinlock was already taken). + The function will never sleep. + + void hwspin_unlock(struct hwspinlock *hwlock); + - unlock a previously-locked hwspinlock. Always succeed, and can be called + from any context (the function never sleeps). Note: code should _never_ + unlock an hwspinlock which is already unlocked (there is no protection + against this). + + void hwspin_unlock_irq(struct hwspinlock *hwlock); + - unlock a previously-locked hwspinlock and enable local interrupts. + The caller should _never_ unlock an hwspinlock which is already unlocked. + Doing so is considered a bug (there is no protection against this). + Upon a successful return from this function, preemption and local + interrupts are enabled. This function will never sleep. + + void + hwspin_unlock_irqrestore(struct hwspinlock *hwlock, unsigned long *flags); + - unlock a previously-locked hwspinlock. + The caller should _never_ unlock an hwspinlock which is already unlocked. + Doing so is considered a bug (there is no protection against this). + Upon a successful return from this function, preemption is reenabled, + and the state of the local interrupts is restored to the state saved at + the given flags. This function will never sleep. + + int hwspin_lock_get_id(struct hwspinlock *hwlock); + - retrieve id number of a given hwspinlock. This is needed when an + hwspinlock is dynamically assigned: before it can be used to achieve + mutual exclusion with a remote cpu, the id number should be communicated + to the remote task with which we want to synchronize. + Returns the hwspinlock id number, or -EINVAL if hwlock is null. + +3. Typical usage + +#include <linux/hwspinlock.h> +#include <linux/err.h> + +int hwspinlock_example1(void) +{ + struct hwspinlock *hwlock; + int ret; + + /* dynamically assign a hwspinlock */ + hwlock = hwspin_lock_request(); + if (!hwlock) + ... + + id = hwspin_lock_get_id(hwlock); + /* probably need to communicate id to a remote processor now */ + + /* take the lock, spin for 1 sec if it's already taken */ + ret = hwspin_lock_timeout(hwlock, 1000); + if (ret) + ... + + /* + * we took the lock, do our thing now, but do NOT sleep + */ + + /* release the lock */ + hwspin_unlock(hwlock); + + /* free the lock */ + ret = hwspin_lock_free(hwlock); + if (ret) + ... + + return ret; +} + +int hwspinlock_example2(void) +{ + struct hwspinlock *hwlock; + int ret; + + /* + * assign a specific hwspinlock id - this should be called early + * by board init code. + */ + hwlock = hwspin_lock_request_specific(PREDEFINED_LOCK_ID); + if (!hwlock) + ... + + /* try to take it, but don't spin on it */ + ret = hwspin_trylock(hwlock); + if (!ret) { + pr_info("lock is already taken\n"); + return -EBUSY; + } + + /* + * we took the lock, do our thing now, but do NOT sleep + */ + + /* release the lock */ + hwspin_unlock(hwlock); + + /* free the lock */ + ret = hwspin_lock_free(hwlock); + if (ret) + ... + + return ret; +} + + +4. API for implementors + + int hwspin_lock_register(struct hwspinlock *hwlock); + - to be called from the underlying platform-specific implementation, in + order to register a new hwspinlock instance. Can be called from an atomic + context (this function will not sleep) but not from within interrupt + context. Returns 0 on success, or appropriate error code on failure. + + struct hwspinlock *hwspin_lock_unregister(unsigned int id); + - to be called from the underlying vendor-specific implementation, in order + to unregister an existing (and unused) hwspinlock instance. + Can be called from an atomic context (will not sleep) but not from + within interrupt context. + Returns the address of hwspinlock on success, or NULL on error (e.g. + if the hwspinlock is sill in use). + +5. struct hwspinlock + +This struct represents an hwspinlock instance. It is registered by the +underlying hwspinlock implementation using the hwspin_lock_register() API. + +/** + * struct hwspinlock - vendor-specific hwspinlock implementation + * + * @dev: underlying device, will be used with runtime PM api + * @ops: vendor-specific hwspinlock handlers + * @id: a global, unique, system-wide, index of the lock. + * @lock: initialized and used by hwspinlock core + * @owner: underlying implementation module, used to maintain module ref count + */ +struct hwspinlock { + struct device *dev; + const struct hwspinlock_ops *ops; + int id; + spinlock_t lock; + struct module *owner; +}; + +The underlying implementation is responsible to assign the dev, ops, id and +owner members. The lock member, OTOH, is initialized and used by the hwspinlock +core. + +6. Implementation callbacks + +There are three possible callbacks defined in 'struct hwspinlock_ops': + +struct hwspinlock_ops { + int (*trylock)(struct hwspinlock *lock); + void (*unlock)(struct hwspinlock *lock); + void (*relax)(struct hwspinlock *lock); +}; + +The first two callbacks are mandatory: + +The ->trylock() callback should make a single attempt to take the lock, and +return 0 on failure and 1 on success. This callback may _not_ sleep. + +The ->unlock() callback releases the lock. It always succeed, and it, too, +may _not_ sleep. + +The ->relax() callback is optional. It is called by hwspinlock core while +spinning on a lock, and can be used by the underlying implementation to force +a delay between two successive invocations of ->trylock(). It may _not_ sleep. diff --git a/Documentation/usb/usbmon.txt b/Documentation/usb/usbmon.txt index 66f92d1194c..a4efa0462f0 100644 --- a/Documentation/usb/usbmon.txt +++ b/Documentation/usb/usbmon.txt @@ -12,6 +12,10 @@ Controller Drivers (HCD). So, if HCD is buggy, the traces reported by usbmon may not correspond to bus transactions precisely. This is the same situation as with tcpdump. +Two APIs are currently implemented: "text" and "binary". The binary API +is available through a character device in /dev namespace and is an ABI. +The text API is deprecated since 2.6.35, but available for convenience. + * How to use usbmon to collect raw text traces Unlike the packet socket, usbmon has an interface which provides traces @@ -162,39 +166,11 @@ Here is the list of words, from left to right: not machine words, but really just a byte stream split into words to make it easier to read. Thus, the last word may contain from one to four bytes. The length of collected data is limited and can be less than the data length - report in Data Length word. - -Here is an example of code to read the data stream in a well known programming -language: - -class ParsedLine { - int data_len; /* Available length of data */ - byte data[]; - - void parseData(StringTokenizer st) { - int availwords = st.countTokens(); - data = new byte[availwords * 4]; - data_len = 0; - while (st.hasMoreTokens()) { - String data_str = st.nextToken(); - int len = data_str.length() / 2; - int i; - int b; // byte is signed, apparently?! XXX - for (i = 0; i < len; i++) { - // data[data_len] = Byte.parseByte( - // data_str.substring(i*2, i*2 + 2), - // 16); - b = Integer.parseInt( - data_str.substring(i*2, i*2 + 2), - 16); - if (b >= 128) - b *= -1; - data[data_len] = (byte) b; - data_len++; - } - } - } -} + reported in the Data Length word. In the case of an Isochronous input (Zi) + completion where the received data is sparse in the buffer, the length of + the collected data can be greater than the Data Length value (because Data + Length counts only the bytes that were received whereas the Data words + contain the entire transfer buffer). Examples: |