aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorJeff Garzik <jeff@garzik.org>2006-05-20 00:03:38 -0400
committerJeff Garzik <jeff@garzik.org>2006-05-20 00:03:38 -0400
commitbadc48e6605ddeeb2484afae5993c859494decaa (patch)
tree7da638f9bb53b1812b71e40ad6deca91d59ad301 /Documentation
parent753a6c4ff4c371a3e4e3408aaba4d03f3cfde73a (diff)
parent2f880b65fdbc2d4915bddc59d75a176329570fdd (diff)
Merge branch 'master' into upstream
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devices.txt5
-rw-r--r--Documentation/feature-removal-schedule.txt9
-rw-r--r--Documentation/memory-barriers.txt4
-rw-r--r--Documentation/networking/operstates.txt161
-rw-r--r--Documentation/scsi/ChangeLog.megaraid25
-rw-r--r--Documentation/spi/pxa2xx234
-rw-r--r--Documentation/spi/spi-summary34
-rw-r--r--Documentation/watchdog/watchdog-api.txt3
8 files changed, 467 insertions, 8 deletions
diff --git a/Documentation/devices.txt b/Documentation/devices.txt
index 3c406acd4dfa..b369a8c46a73 100644
--- a/Documentation/devices.txt
+++ b/Documentation/devices.txt
@@ -1721,11 +1721,6 @@ Your cooperation is appreciated.
1721 These devices support the same API as the generic SCSI 1721 These devices support the same API as the generic SCSI
1722 devices. 1722 devices.
1723 1723
1724 97 block Packet writing for CD/DVD devices
1725 0 = /dev/pktcdvd0 First packet-writing module
1726 1 = /dev/pktcdvd1 Second packet-writing module
1727 ...
1728
1729 98 char Control and Measurement Device (comedi) 1724 98 char Control and Measurement Device (comedi)
1730 0 = /dev/comedi0 First comedi device 1725 0 = /dev/comedi0 First comedi device
1731 1 = /dev/comedi1 Second comedi device 1726 1 = /dev/comedi1 Second comedi device
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index 421bcfff6ad2..43ab119963d5 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -57,6 +57,15 @@ Who: Jody McIntyre <scjody@steamballoon.com>
57 57
58--------------------------- 58---------------------------
59 59
60What: sbp2: module parameter "force_inquiry_hack"
61When: July 2006
62Why: Superceded by parameter "workarounds". Both parameters are meant to be
63 used ad-hoc and for single devices only, i.e. not in modprobe.conf,
64 therefore the impact of this feature replacement should be low.
65Who: Stefan Richter <stefanr@s5r6.in-berlin.de>
66
67---------------------------
68
60What: Video4Linux API 1 ioctls and video_decoder.h from Video devices. 69What: Video4Linux API 1 ioctls and video_decoder.h from Video devices.
61When: July 2006 70When: July 2006
62Why: V4L1 AP1 was replaced by V4L2 API. during migration from 2.4 to 2.6 71Why: V4L1 AP1 was replaced by V4L2 API. during migration from 2.4 to 2.6
diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt
index 92f0056d928c..c61d8b876fdb 100644
--- a/Documentation/memory-barriers.txt
+++ b/Documentation/memory-barriers.txt
@@ -1031,7 +1031,7 @@ conflict on any particular lock.
1031LOCKS VS MEMORY ACCESSES 1031LOCKS VS MEMORY ACCESSES
1032------------------------ 1032------------------------
1033 1033
1034Consider the following: the system has a pair of spinlocks (N) and (Q), and 1034Consider the following: the system has a pair of spinlocks (M) and (Q), and
1035three CPUs; then should the following sequence of events occur: 1035three CPUs; then should the following sequence of events occur:
1036 1036
1037 CPU 1 CPU 2 1037 CPU 1 CPU 2
@@ -1678,7 +1678,7 @@ CPU's caches by some other cache event:
1678 smp_wmb(); 1678 smp_wmb();
1679 <A:modify v=2> <C:busy> 1679 <A:modify v=2> <C:busy>
1680 <C:queue v=2> 1680 <C:queue v=2>
1681 p = &b; q = p; 1681 p = &v; q = p;
1682 <D:request p> 1682 <D:request p>
1683 <B:modify p=&v> <D:commit p=&v> 1683 <B:modify p=&v> <D:commit p=&v>
1684 <D:read p> 1684 <D:read p>
diff --git a/Documentation/networking/operstates.txt b/Documentation/networking/operstates.txt
new file mode 100644
index 000000000000..4a21d9bb836b
--- /dev/null
+++ b/Documentation/networking/operstates.txt
@@ -0,0 +1,161 @@
1
21. Introduction
3
4Linux distinguishes between administrative and operational state of an
5interface. Admininstrative state is the result of "ip link set dev
6<dev> up or down" and reflects whether the administrator wants to use
7the device for traffic.
8
9However, an interface is not usable just because the admin enabled it
10- ethernet requires to be plugged into the switch and, depending on
11a site's networking policy and configuration, an 802.1X authentication
12to be performed before user data can be transferred. Operational state
13shows the ability of an interface to transmit this user data.
14
15Thanks to 802.1X, userspace must be granted the possibility to
16influence operational state. To accommodate this, operational state is
17split into two parts: Two flags that can be set by the driver only, and
18a RFC2863 compatible state that is derived from these flags, a policy,
19and changeable from userspace under certain rules.
20
21
222. Querying from userspace
23
24Both admin and operational state can be queried via the netlink
25operation RTM_GETLINK. It is also possible to subscribe to RTMGRP_LINK
26to be notified of updates. This is important for setting from userspace.
27
28These values contain interface state:
29
30ifinfomsg::if_flags & IFF_UP:
31 Interface is admin up
32ifinfomsg::if_flags & IFF_RUNNING:
33 Interface is in RFC2863 operational state UP or UNKNOWN. This is for
34 backward compatibility, routing daemons, dhcp clients can use this
35 flag to determine whether they should use the interface.
36ifinfomsg::if_flags & IFF_LOWER_UP:
37 Driver has signaled netif_carrier_on()
38ifinfomsg::if_flags & IFF_DORMANT:
39 Driver has signaled netif_dormant_on()
40
41These interface flags can also be queried without netlink using the
42SIOCGIFFLAGS ioctl.
43
44TLV IFLA_OPERSTATE
45
46contains RFC2863 state of the interface in numeric representation:
47
48IF_OPER_UNKNOWN (0):
49 Interface is in unknown state, neither driver nor userspace has set
50 operational state. Interface must be considered for user data as
51 setting operational state has not been implemented in every driver.
52IF_OPER_NOTPRESENT (1):
53 Unused in current kernel (notpresent interfaces normally disappear),
54 just a numerical placeholder.
55IF_OPER_DOWN (2):
56 Interface is unable to transfer data on L1, f.e. ethernet is not
57 plugged or interface is ADMIN down.
58IF_OPER_LOWERLAYERDOWN (3):
59 Interfaces stacked on an interface that is IF_OPER_DOWN show this
60 state (f.e. VLAN).
61IF_OPER_TESTING (4):
62 Unused in current kernel.
63IF_OPER_DORMANT (5):
64 Interface is L1 up, but waiting for an external event, f.e. for a
65 protocol to establish. (802.1X)
66IF_OPER_UP (6):
67 Interface is operational up and can be used.
68
69This TLV can also be queried via sysfs.
70
71TLV IFLA_LINKMODE
72
73contains link policy. This is needed for userspace interaction
74described below.
75
76This TLV can also be queried via sysfs.
77
78
793. Kernel driver API
80
81Kernel drivers have access to two flags that map to IFF_LOWER_UP and
82IFF_DORMANT. These flags can be set from everywhere, even from
83interrupts. It is guaranteed that only the driver has write access,
84however, if different layers of the driver manipulate the same flag,
85the driver has to provide the synchronisation needed.
86
87__LINK_STATE_NOCARRIER, maps to !IFF_LOWER_UP:
88
89The driver uses netif_carrier_on() to clear and netif_carrier_off() to
90set this flag. On netif_carrier_off(), the scheduler stops sending
91packets. The name 'carrier' and the inversion are historical, think of
92it as lower layer.
93
94netif_carrier_ok() can be used to query that bit.
95
96__LINK_STATE_DORMANT, maps to IFF_DORMANT:
97
98Set by the driver to express that the device cannot yet be used
99because some driver controlled protocol establishment has to
100complete. Corresponding functions are netif_dormant_on() to set the
101flag, netif_dormant_off() to clear it and netif_dormant() to query.
102
103On device allocation, networking core sets the flags equivalent to
104netif_carrier_ok() and !netif_dormant().
105
106
107Whenever the driver CHANGES one of these flags, a workqueue event is
108scheduled to translate the flag combination to IFLA_OPERSTATE as
109follows:
110
111!netif_carrier_ok():
112 IF_OPER_LOWERLAYERDOWN if the interface is stacked, IF_OPER_DOWN
113 otherwise. Kernel can recognise stacked interfaces because their
114 ifindex != iflink.
115
116netif_carrier_ok() && netif_dormant():
117 IF_OPER_DORMANT
118
119netif_carrier_ok() && !netif_dormant():
120 IF_OPER_UP if userspace interaction is disabled. Otherwise
121 IF_OPER_DORMANT with the possibility for userspace to initiate the
122 IF_OPER_UP transition afterwards.
123
124
1254. Setting from userspace
126
127Applications have to use the netlink interface to influence the
128RFC2863 operational state of an interface. Setting IFLA_LINKMODE to 1
129via RTM_SETLINK instructs the kernel that an interface should go to
130IF_OPER_DORMANT instead of IF_OPER_UP when the combination
131netif_carrier_ok() && !netif_dormant() is set by the
132driver. Afterwards, the userspace application can set IFLA_OPERSTATE
133to IF_OPER_DORMANT or IF_OPER_UP as long as the driver does not set
134netif_carrier_off() or netif_dormant_on(). Changes made by userspace
135are multicasted on the netlink group RTMGRP_LINK.
136
137So basically a 802.1X supplicant interacts with the kernel like this:
138
139-subscribe to RTMGRP_LINK
140-set IFLA_LINKMODE to 1 via RTM_SETLINK
141-query RTM_GETLINK once to get initial state
142-if initial flags are not (IFF_LOWER_UP && !IFF_DORMANT), wait until
143 netlink multicast signals this state
144-do 802.1X, eventually abort if flags go down again
145-send RTM_SETLINK to set operstate to IF_OPER_UP if authentication
146 succeeds, IF_OPER_DORMANT otherwise
147-see how operstate and IFF_RUNNING is echoed via netlink multicast
148-set interface back to IF_OPER_DORMANT if 802.1X reauthentication
149 fails
150-restart if kernel changes IFF_LOWER_UP or IFF_DORMANT flag
151
152if supplicant goes down, bring back IFLA_LINKMODE to 0 and
153IFLA_OPERSTATE to a sane value.
154
155A routing daemon or dhcp client just needs to care for IFF_RUNNING or
156waiting for operstate to go IF_OPER_UP/IF_OPER_UNKNOWN before
157considering the interface / querying a DHCP address.
158
159
160For technical questions and/or comments please e-mail to Stefan Rompf
161(stefan at loplof.de).
diff --git a/Documentation/scsi/ChangeLog.megaraid b/Documentation/scsi/ChangeLog.megaraid
index 09f6300eda4b..c173806c91fa 100644
--- a/Documentation/scsi/ChangeLog.megaraid
+++ b/Documentation/scsi/ChangeLog.megaraid
@@ -1,3 +1,28 @@
1Release Date : Mon Apr 11 12:27:22 EST 2006 - Seokmann Ju <sju@lsil.com>
2Current Version : 2.20.4.8 (scsi module), 2.20.2.6 (cmm module)
3Older Version : 2.20.4.7 (scsi module), 2.20.2.6 (cmm module)
4
51. Fixed a bug in megaraid_reset_handler().
6 Customer reported "Unable to handle kernel NULL pointer dereference
7 at virtual address 00000000" when system goes to reset condition
8 for some reason. It happened randomly.
9 Root Cause: in the megaraid_reset_handler(), there is possibility not
10 returning pending packets in the pend_list if there are multiple
11 pending packets.
12 Fix: Made the change in the driver so that it will return all packets
13 in the pend_list.
14
152. Added change request.
16 As found in the following URL, rmb() only didn't help the
17 problem. I had to increase the loop counter to 0xFFFFFF. (6 F's)
18 http://marc.theaimsgroup.com/?l=linux-scsi&m=110971060502497&w=2
19
20 I attached a patch for your reference, too.
21 Could you check and get this fix in your driver?
22
23 Best Regards,
24 Jun'ichi Nomura
25
1Release Date : Fri Nov 11 12:27:22 EST 2005 - Seokmann Ju <sju@lsil.com> 26Release Date : Fri Nov 11 12:27:22 EST 2005 - Seokmann Ju <sju@lsil.com>
2Current Version : 2.20.4.7 (scsi module), 2.20.2.6 (cmm module) 27Current Version : 2.20.4.7 (scsi module), 2.20.2.6 (cmm module)
3Older Version : 2.20.4.6 (scsi module), 2.20.2.6 (cmm module) 28Older Version : 2.20.4.6 (scsi module), 2.20.2.6 (cmm module)
diff --git a/Documentation/spi/pxa2xx b/Documentation/spi/pxa2xx
new file mode 100644
index 000000000000..9c45f3df2e18
--- /dev/null
+++ b/Documentation/spi/pxa2xx
@@ -0,0 +1,234 @@
1PXA2xx SPI on SSP driver HOWTO
2===================================================
3This a mini howto on the pxa2xx_spi driver. The driver turns a PXA2xx
4synchronous serial port into a SPI master controller
5(see Documentation/spi/spi_summary). The driver has the following features
6
7- Support for any PXA2xx SSP
8- SSP PIO and SSP DMA data transfers.
9- External and Internal (SSPFRM) chip selects.
10- Per slave device (chip) configuration.
11- Full suspend, freeze, resume support.
12
13The driver is built around a "spi_message" fifo serviced by workqueue and a
14tasklet. The workqueue, "pump_messages", drives message fifo and the tasklet
15(pump_transfer) is responsible for queuing SPI transactions and setting up and
16launching the dma/interrupt driven transfers.
17
18Declaring PXA2xx Master Controllers
19-----------------------------------
20Typically a SPI master is defined in the arch/.../mach-*/board-*.c as a
21"platform device". The master configuration is passed to the driver via a table
22found in include/asm-arm/arch-pxa/pxa2xx_spi.h:
23
24struct pxa2xx_spi_master {
25 enum pxa_ssp_type ssp_type;
26 u32 clock_enable;
27 u16 num_chipselect;
28 u8 enable_dma;
29};
30
31The "pxa2xx_spi_master.ssp_type" field must have a value between 1 and 3 and
32informs the driver which features a particular SSP supports.
33
34The "pxa2xx_spi_master.clock_enable" field is used to enable/disable the
35corresponding SSP peripheral block in the "Clock Enable Register (CKEN"). See
36the "PXA2xx Developer Manual" section "Clocks and Power Management".
37
38The "pxa2xx_spi_master.num_chipselect" field is used to determine the number of
39slave device (chips) attached to this SPI master.
40
41The "pxa2xx_spi_master.enable_dma" field informs the driver that SSP DMA should
42be used. This caused the driver to acquire two DMA channels: rx_channel and
43tx_channel. The rx_channel has a higher DMA service priority the tx_channel.
44See the "PXA2xx Developer Manual" section "DMA Controller".
45
46NSSP MASTER SAMPLE
47------------------
48Below is a sample configuration using the PXA255 NSSP.
49
50static struct resource pxa_spi_nssp_resources[] = {
51 [0] = {
52 .start = __PREG(SSCR0_P(2)), /* Start address of NSSP */
53 .end = __PREG(SSCR0_P(2)) + 0x2c, /* Range of registers */
54 .flags = IORESOURCE_MEM,
55 },
56 [1] = {
57 .start = IRQ_NSSP, /* NSSP IRQ */
58 .end = IRQ_NSSP,
59 .flags = IORESOURCE_IRQ,
60 },
61};
62
63static struct pxa2xx_spi_master pxa_nssp_master_info = {
64 .ssp_type = PXA25x_NSSP, /* Type of SSP */
65 .clock_enable = CKEN9_NSSP, /* NSSP Peripheral clock */
66 .num_chipselect = 1, /* Matches the number of chips attached to NSSP */
67 .enable_dma = 1, /* Enables NSSP DMA */
68};
69
70static struct platform_device pxa_spi_nssp = {
71 .name = "pxa2xx-spi", /* MUST BE THIS VALUE, so device match driver */
72 .id = 2, /* Bus number, MUST MATCH SSP number 1..n */
73 .resource = pxa_spi_nssp_resources,
74 .num_resources = ARRAY_SIZE(pxa_spi_nssp_resources),
75 .dev = {
76 .platform_data = &pxa_nssp_master_info, /* Passed to driver */
77 },
78};
79
80static struct platform_device *devices[] __initdata = {
81 &pxa_spi_nssp,
82};
83
84static void __init board_init(void)
85{
86 (void)platform_add_device(devices, ARRAY_SIZE(devices));
87}
88
89Declaring Slave Devices
90-----------------------
91Typically each SPI slave (chip) is defined in the arch/.../mach-*/board-*.c
92using the "spi_board_info" structure found in "linux/spi/spi.h". See
93"Documentation/spi/spi_summary" for additional information.
94
95Each slave device attached to the PXA must provide slave specific configuration
96information via the structure "pxa2xx_spi_chip" found in
97"include/asm-arm/arch-pxa/pxa2xx_spi.h". The pxa2xx_spi master controller driver
98will uses the configuration whenever the driver communicates with the slave
99device.
100
101struct pxa2xx_spi_chip {
102 u8 tx_threshold;
103 u8 rx_threshold;
104 u8 dma_burst_size;
105 u32 timeout_microsecs;
106 u8 enable_loopback;
107 void (*cs_control)(u32 command);
108};
109
110The "pxa2xx_spi_chip.tx_threshold" and "pxa2xx_spi_chip.rx_threshold" fields are
111used to configure the SSP hardware fifo. These fields are critical to the
112performance of pxa2xx_spi driver and misconfiguration will result in rx
113fifo overruns (especially in PIO mode transfers). Good default values are
114
115 .tx_threshold = 12,
116 .rx_threshold = 4,
117
118The "pxa2xx_spi_chip.dma_burst_size" field is used to configure PXA2xx DMA
119engine and is related the "spi_device.bits_per_word" field. Read and understand
120the PXA2xx "Developer Manual" sections on the DMA controller and SSP Controllers
121to determine the correct value. An SSP configured for byte-wide transfers would
122use a value of 8.
123
124The "pxa2xx_spi_chip.timeout_microsecs" fields is used to efficiently handle
125trailing bytes in the SSP receiver fifo. The correct value for this field is
126dependent on the SPI bus speed ("spi_board_info.max_speed_hz") and the specific
127slave device. Please note the the PXA2xx SSP 1 does not support trailing byte
128timeouts and must busy-wait any trailing bytes.
129
130The "pxa2xx_spi_chip.enable_loopback" field is used to place the SSP porting
131into internal loopback mode. In this mode the SSP controller internally
132connects the SSPTX pin the the SSPRX pin. This is useful for initial setup
133testing.
134
135The "pxa2xx_spi_chip.cs_control" field is used to point to a board specific
136function for asserting/deasserting a slave device chip select. If the field is
137NULL, the pxa2xx_spi master controller driver assumes that the SSP port is
138configured to use SSPFRM instead.
139
140NSSP SALVE SAMPLE
141-----------------
142The pxa2xx_spi_chip structure is passed to the pxa2xx_spi driver in the
143"spi_board_info.controller_data" field. Below is a sample configuration using
144the PXA255 NSSP.
145
146/* Chip Select control for the CS8415A SPI slave device */
147static void cs8415a_cs_control(u32 command)
148{
149 if (command & PXA2XX_CS_ASSERT)
150 GPCR(2) = GPIO_bit(2);
151 else
152 GPSR(2) = GPIO_bit(2);
153}
154
155/* Chip Select control for the CS8405A SPI slave device */
156static void cs8405a_cs_control(u32 command)
157{
158 if (command & PXA2XX_CS_ASSERT)
159 GPCR(3) = GPIO_bit(3);
160 else
161 GPSR(3) = GPIO_bit(3);
162}
163
164static struct pxa2xx_spi_chip cs8415a_chip_info = {
165 .tx_threshold = 12, /* SSP hardward FIFO threshold */
166 .rx_threshold = 4, /* SSP hardward FIFO threshold */
167 .dma_burst_size = 8, /* Byte wide transfers used so 8 byte bursts */
168 .timeout_microsecs = 64, /* Wait at least 64usec to handle trailing */
169 .cs_control = cs8415a_cs_control, /* Use external chip select */
170};
171
172static struct pxa2xx_spi_chip cs8405a_chip_info = {
173 .tx_threshold = 12, /* SSP hardward FIFO threshold */
174 .rx_threshold = 4, /* SSP hardward FIFO threshold */
175 .dma_burst_size = 8, /* Byte wide transfers used so 8 byte bursts */
176 .timeout_microsecs = 64, /* Wait at least 64usec to handle trailing */
177 .cs_control = cs8405a_cs_control, /* Use external chip select */
178};
179
180static struct spi_board_info streetracer_spi_board_info[] __initdata = {
181 {
182 .modalias = "cs8415a", /* Name of spi_driver for this device */
183 .max_speed_hz = 3686400, /* Run SSP as fast a possbile */
184 .bus_num = 2, /* Framework bus number */
185 .chip_select = 0, /* Framework chip select */
186 .platform_data = NULL; /* No spi_driver specific config */
187 .controller_data = &cs8415a_chip_info, /* Master chip config */
188 .irq = STREETRACER_APCI_IRQ, /* Slave device interrupt */
189 },
190 {
191 .modalias = "cs8405a", /* Name of spi_driver for this device */
192 .max_speed_hz = 3686400, /* Run SSP as fast a possbile */
193 .bus_num = 2, /* Framework bus number */
194 .chip_select = 1, /* Framework chip select */
195 .controller_data = &cs8405a_chip_info, /* Master chip config */
196 .irq = STREETRACER_APCI_IRQ, /* Slave device interrupt */
197 },
198};
199
200static void __init streetracer_init(void)
201{
202 spi_register_board_info(streetracer_spi_board_info,
203 ARRAY_SIZE(streetracer_spi_board_info));
204}
205
206
207DMA and PIO I/O Support
208-----------------------
209The pxa2xx_spi driver support both DMA and interrupt driven PIO message
210transfers. The driver defaults to PIO mode and DMA transfers must enabled by
211setting the "enable_dma" flag in the "pxa2xx_spi_master" structure and and
212ensuring that the "pxa2xx_spi_chip.dma_burst_size" field is non-zero. The DMA
213mode support both coherent and stream based DMA mappings.
214
215The following logic is used to determine the type of I/O to be used on
216a per "spi_transfer" basis:
217
218if !enable_dma or dma_burst_size == 0 then
219 always use PIO transfers
220
221if spi_message.is_dma_mapped and rx_dma_buf != 0 and tx_dma_buf != 0 then
222 use coherent DMA mode
223
224if rx_buf and tx_buf are aligned on 8 byte boundary then
225 use streaming DMA mode
226
227otherwise
228 use PIO transfer
229
230THANKS TO
231---------
232
233David Brownell and others for mentoring the development of this driver.
234
diff --git a/Documentation/spi/spi-summary b/Documentation/spi/spi-summary
index a5ffba33a351..068732d32276 100644
--- a/Documentation/spi/spi-summary
+++ b/Documentation/spi/spi-summary
@@ -414,7 +414,33 @@ to get the driver-private data allocated for that device.
414The driver will initialize the fields of that spi_master, including the 414The driver will initialize the fields of that spi_master, including the
415bus number (maybe the same as the platform device ID) and three methods 415bus number (maybe the same as the platform device ID) and three methods
416used to interact with the SPI core and SPI protocol drivers. It will 416used to interact with the SPI core and SPI protocol drivers. It will
417also initialize its own internal state. 417also initialize its own internal state. (See below about bus numbering
418and those methods.)
419
420After you initialize the spi_master, then use spi_register_master() to
421publish it to the rest of the system. At that time, device nodes for
422the controller and any predeclared spi devices will be made available,
423and the driver model core will take care of binding them to drivers.
424
425If you need to remove your SPI controller driver, spi_unregister_master()
426will reverse the effect of spi_register_master().
427
428
429BUS NUMBERING
430
431Bus numbering is important, since that's how Linux identifies a given
432SPI bus (shared SCK, MOSI, MISO). Valid bus numbers start at zero. On
433SOC systems, the bus numbers should match the numbers defined by the chip
434manufacturer. For example, hardware controller SPI2 would be bus number 2,
435and spi_board_info for devices connected to it would use that number.
436
437If you don't have such hardware-assigned bus number, and for some reason
438you can't just assign them, then provide a negative bus number. That will
439then be replaced by a dynamically assigned number. You'd then need to treat
440this as a non-static configuration (see above).
441
442
443SPI MASTER METHODS
418 444
419 master->setup(struct spi_device *spi) 445 master->setup(struct spi_device *spi)
420 This sets up the device clock rate, SPI mode, and word sizes. 446 This sets up the device clock rate, SPI mode, and word sizes.
@@ -431,6 +457,9 @@ also initialize its own internal state.
431 state it dynamically associates with that device. If you do that, 457 state it dynamically associates with that device. If you do that,
432 be sure to provide the cleanup() method to free that state. 458 be sure to provide the cleanup() method to free that state.
433 459
460
461SPI MESSAGE QUEUE
462
434The bulk of the driver will be managing the I/O queue fed by transfer(). 463The bulk of the driver will be managing the I/O queue fed by transfer().
435 464
436That queue could be purely conceptual. For example, a driver used only 465That queue could be purely conceptual. For example, a driver used only
@@ -440,6 +469,9 @@ But the queue will probably be very real, using message->queue, PIO,
440often DMA (especially if the root filesystem is in SPI flash), and 469often DMA (especially if the root filesystem is in SPI flash), and
441execution contexts like IRQ handlers, tasklets, or workqueues (such 470execution contexts like IRQ handlers, tasklets, or workqueues (such
442as keventd). Your driver can be as fancy, or as simple, as you need. 471as keventd). Your driver can be as fancy, or as simple, as you need.
472Such a transfer() method would normally just add the message to a
473queue, and then start some asynchronous transfer engine (unless it's
474already running).
443 475
444 476
445THANKS TO 477THANKS TO
diff --git a/Documentation/watchdog/watchdog-api.txt b/Documentation/watchdog/watchdog-api.txt
index c5beb548cfc4..21ed51173662 100644
--- a/Documentation/watchdog/watchdog-api.txt
+++ b/Documentation/watchdog/watchdog-api.txt
@@ -36,6 +36,9 @@ timeout or margin. The simplest way to ping the watchdog is to write
36some data to the device. So a very simple watchdog daemon would look 36some data to the device. So a very simple watchdog daemon would look
37like this: 37like this:
38 38
39#include <stdlib.h>
40#include <fcntl.h>
41
39int main(int argc, const char *argv[]) { 42int main(int argc, const char *argv[]) {
40 int fd=open("/dev/watchdog",O_WRONLY); 43 int fd=open("/dev/watchdog",O_WRONLY);
41 if (fd==-1) { 44 if (fd==-1) {