diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/hayes-esp.txt |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'Documentation/hayes-esp.txt')
-rw-r--r-- | Documentation/hayes-esp.txt | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/Documentation/hayes-esp.txt b/Documentation/hayes-esp.txt new file mode 100644 index 000000000000..09b5d5856758 --- /dev/null +++ b/Documentation/hayes-esp.txt | |||
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1 | HAYES ESP DRIVER VERSION 2.1 | ||
2 | |||
3 | A big thanks to the people at Hayes, especially Alan Adamson. Their support | ||
4 | has enabled me to provide enhancements to the driver. | ||
5 | |||
6 | Please report your experiences with this driver to me (arobinso@nyx.net). I | ||
7 | am looking for both positive and negative feedback. | ||
8 | |||
9 | *** IMPORTANT CHANGES FOR 2.1 *** | ||
10 | Support for PIO mode. Five situations will cause PIO mode to be used: | ||
11 | 1) A multiport card is detected. PIO mode will always be used. (8 port cards | ||
12 | do not support DMA). | ||
13 | 2) The DMA channel is set to an invalid value (anything other than 1 or 3). | ||
14 | 3) The DMA buffer/channel could not be allocated. The port will revert to PIO | ||
15 | mode until it is reopened. | ||
16 | 4) Less than a specified number of bytes need to be transferred to/from the | ||
17 | FIFOs. PIO mode will be used for that transfer only. | ||
18 | 5) A port needs to do a DMA transfer and another port is already using the | ||
19 | DMA channel. PIO mode will be used for that transfer only. | ||
20 | |||
21 | Since the Hayes ESP seems to conflict with other cards (notably sound cards) | ||
22 | when using DMA, DMA is turned off by default. To use DMA, it must be turned | ||
23 | on explicitly, either with the "dma=" option described below or with | ||
24 | setserial. A multiport card can be forced into DMA mode by using setserial; | ||
25 | however, most multiport cards don't support DMA. | ||
26 | |||
27 | The latest version of setserial allows the enhanced configuration of the ESP | ||
28 | card to be viewed and modified. | ||
29 | *** | ||
30 | |||
31 | This package contains the files needed to compile a module to support the Hayes | ||
32 | ESP card. The drivers are basically a modified version of the serial drivers. | ||
33 | |||
34 | Features: | ||
35 | |||
36 | - Uses the enhanced mode of the ESP card, allowing a wider range of | ||
37 | interrupts and features than compatibility mode | ||
38 | - Uses DMA and 16 bit PIO mode to transfer data to and from the ESP's FIFOs, | ||
39 | reducing CPU load | ||
40 | - Supports primary and secondary ports | ||
41 | |||
42 | |||
43 | If the driver is compiled as a module, the IRQs to use can be specified by | ||
44 | using the irq= option. The format is: | ||
45 | |||
46 | irq=[0x100],[0x140],[0x180],[0x200],[0x240],[0x280],[0x300],[0x380] | ||
47 | |||
48 | The address in brackets is the base address of the card. The IRQ of | ||
49 | nonexistent cards can be set to 0. If an IRQ of a card that does exist is set | ||
50 | to 0, the driver will attempt to guess at the correct IRQ. For example, to set | ||
51 | the IRQ of the card at address 0x300 to 12, the insmod command would be: | ||
52 | |||
53 | insmod esp irq=0,0,0,0,0,0,12,0 | ||
54 | |||
55 | The custom divisor can be set by using the divisor= option. The format is the | ||
56 | same as for the irq= option. Each divisor value is a series of hex digits, | ||
57 | with each digit representing the divisor to use for a corresponding port. The | ||
58 | divisor value is constructed RIGHT TO LEFT. Specifying a nonzero divisor value | ||
59 | will automatically set the spd_cust flag. To calculate the divisor to use for | ||
60 | a certain baud rate, divide the port's base baud (generally 921600) by the | ||
61 | desired rate. For example, to set the divisor of the primary port at 0x300 to | ||
62 | 4 and the divisor of the secondary port at 0x308 to 8, the insmod command would | ||
63 | be: | ||
64 | |||
65 | insmod esp divisor=0,0,0,0,0,0,0x84,0 | ||
66 | |||
67 | The dma= option can be used to set the DMA channel. The channel can be either | ||
68 | 1 or 3. Specifying any other value will force the driver to use PIO mode. | ||
69 | For example, to set the DMA channel to 3, the insmod command would be: | ||
70 | |||
71 | insmod esp dma=3 | ||
72 | |||
73 | The rx_trigger= and tx_trigger= options can be used to set the FIFO trigger | ||
74 | levels. They specify when the ESP card should send an interrupt. Larger | ||
75 | values will decrease the number of interrupts; however, a value too high may | ||
76 | result in data loss. Valid values are 1 through 1023, with 768 being the | ||
77 | default. For example, to set the receive trigger level to 512 bytes and the | ||
78 | transmit trigger level to 700 bytes, the insmod command would be: | ||
79 | |||
80 | insmod esp rx_trigger=512 tx_trigger=700 | ||
81 | |||
82 | The flow_off= and flow_on= options can be used to set the hardware flow off/ | ||
83 | flow on levels. The flow on level must be lower than the flow off level, and | ||
84 | the flow off level should be higher than rx_trigger. Valid values are 1 | ||
85 | through 1023, with 1016 being the default flow off level and 944 being the | ||
86 | default flow on level. For example, to set the flow off level to 1000 bytes | ||
87 | and the flow on level to 935 bytes, the insmod command would be: | ||
88 | |||
89 | insmod esp flow_off=1000 flow_on=935 | ||
90 | |||
91 | The rx_timeout= option can be used to set the receive timeout value. This | ||
92 | value indicates how long after receiving the last character that the ESP card | ||
93 | should wait before signalling an interrupt. Valid values are 0 though 255, | ||
94 | with 128 being the default. A value too high will increase latency, and a | ||
95 | value too low will cause unnecessary interrupts. For example, to set the | ||
96 | receive timeout to 255, the insmod command would be: | ||
97 | |||
98 | insmod esp rx_timeout=255 | ||
99 | |||
100 | The pio_threshold= option sets the threshold (in number of characters) for | ||
101 | using PIO mode instead of DMA mode. For example, if this value is 32, | ||
102 | transfers of 32 bytes or less will always use PIO mode. | ||
103 | |||
104 | insmod esp pio_threshold=32 | ||
105 | |||
106 | Multiple options can be listed on the insmod command line by separating each | ||
107 | option with a space. For example: | ||
108 | |||
109 | insmod esp dma=3 trigger=512 | ||
110 | |||
111 | The esp module can be automatically loaded when needed. To cause this to | ||
112 | happen, add the following lines to /etc/modprobe.conf (replacing the last line | ||
113 | with options for your configuration): | ||
114 | |||
115 | alias char-major-57 esp | ||
116 | alias char-major-58 esp | ||
117 | options esp irq=0,0,0,0,0,0,3,0 divisor=0,0,0,0,0,0,0x4,0 | ||
118 | |||
119 | You may also need to run 'depmod -a'. | ||
120 | |||
121 | Devices must be created manually. To create the devices, note the output from | ||
122 | the module after it is inserted. The output will appear in the location where | ||
123 | kernel messages usually appear (usually /var/adm/messages). Create two devices | ||
124 | for each 'tty' mentioned, one with major of 57 and the other with major of 58. | ||
125 | The minor number should be the same as the tty number reported. The commands | ||
126 | would be (replace ? with the tty number): | ||
127 | |||
128 | mknod /dev/ttyP? c 57 ? | ||
129 | mknod /dev/cup? c 58 ? | ||
130 | |||
131 | For example, if the following line appears: | ||
132 | |||
133 | Oct 24 18:17:23 techno kernel: ttyP8 at 0x0140 (irq = 3) is an ESP primary port | ||
134 | |||
135 | ...two devices should be created: | ||
136 | |||
137 | mknod /dev/ttyP8 c 57 8 | ||
138 | mknod /dev/cup8 c 58 8 | ||
139 | |||
140 | You may need to set the permissions on the devices: | ||
141 | |||
142 | chmod 666 /dev/ttyP* | ||
143 | chmod 666 /dev/cup* | ||
144 | |||
145 | The ESP module and the serial module should not conflict (they can be used at | ||
146 | the same time). After the ESP module has been loaded the ports on the ESP card | ||
147 | will no longer be accessible by the serial driver. | ||
148 | |||
149 | If I/O errors are experienced when accessing the port, check for IRQ and DMA | ||
150 | conflicts ('cat /proc/interrupts' and 'cat /proc/dma' for a list of IRQs and | ||
151 | DMAs currently in use). | ||
152 | |||
153 | Enjoy! | ||
154 | Andrew J. Robinson <arobinso@nyx.net> | ||