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Diffstat (limited to 'Documentation/serial')
| -rw-r--r-- | Documentation/serial/hayes-esp.txt | 154 |
1 files changed, 0 insertions, 154 deletions
diff --git a/Documentation/serial/hayes-esp.txt b/Documentation/serial/hayes-esp.txt deleted file mode 100644 index 09b5d585675..00000000000 --- a/Documentation/serial/hayes-esp.txt +++ /dev/null @@ -1,154 +0,0 @@ -HAYES ESP DRIVER VERSION 2.1 - -A big thanks to the people at Hayes, especially Alan Adamson. Their support -has enabled me to provide enhancements to the driver. - -Please report your experiences with this driver to me (arobinso@nyx.net). I -am looking for both positive and negative feedback. - -*** IMPORTANT CHANGES FOR 2.1 *** -Support for PIO mode. Five situations will cause PIO mode to be used: -1) A multiport card is detected. PIO mode will always be used. (8 port cards -do not support DMA). -2) The DMA channel is set to an invalid value (anything other than 1 or 3). -3) The DMA buffer/channel could not be allocated. The port will revert to PIO -mode until it is reopened. -4) Less than a specified number of bytes need to be transferred to/from the -FIFOs. PIO mode will be used for that transfer only. -5) A port needs to do a DMA transfer and another port is already using the -DMA channel. PIO mode will be used for that transfer only. - -Since the Hayes ESP seems to conflict with other cards (notably sound cards) -when using DMA, DMA is turned off by default. To use DMA, it must be turned -on explicitly, either with the "dma=" option described below or with -setserial. A multiport card can be forced into DMA mode by using setserial; -however, most multiport cards don't support DMA. - -The latest version of setserial allows the enhanced configuration of the ESP -card to be viewed and modified. -*** - -This package contains the files needed to compile a module to support the Hayes -ESP card. The drivers are basically a modified version of the serial drivers. - -Features: - -- Uses the enhanced mode of the ESP card, allowing a wider range of - interrupts and features than compatibility mode -- Uses DMA and 16 bit PIO mode to transfer data to and from the ESP's FIFOs, - reducing CPU load -- Supports primary and secondary ports - - -If the driver is compiled as a module, the IRQs to use can be specified by -using the irq= option. The format is: - -irq=[0x100],[0x140],[0x180],[0x200],[0x240],[0x280],[0x300],[0x380] - -The address in brackets is the base address of the card. The IRQ of -nonexistent cards can be set to 0. If an IRQ of a card that does exist is set -to 0, the driver will attempt to guess at the correct IRQ. For example, to set -the IRQ of the card at address 0x300 to 12, the insmod command would be: - -insmod esp irq=0,0,0,0,0,0,12,0 - -The custom divisor can be set by using the divisor= option. The format is the -same as for the irq= option. Each divisor value is a series of hex digits, -with each digit representing the divisor to use for a corresponding port. The -divisor value is constructed RIGHT TO LEFT. Specifying a nonzero divisor value -will automatically set the spd_cust flag. To calculate the divisor to use for -a certain baud rate, divide the port's base baud (generally 921600) by the -desired rate. For example, to set the divisor of the primary port at 0x300 to -4 and the divisor of the secondary port at 0x308 to 8, the insmod command would -be: - -insmod esp divisor=0,0,0,0,0,0,0x84,0 - -The dma= option can be used to set the DMA channel. The channel can be either -1 or 3. Specifying any other value will force the driver to use PIO mode. -For example, to set the DMA channel to 3, the insmod command would be: - -insmod esp dma=3 - -The rx_trigger= and tx_trigger= options can be used to set the FIFO trigger -levels. They specify when the ESP card should send an interrupt. Larger -values will decrease the number of interrupts; however, a value too high may -result in data loss. Valid values are 1 through 1023, with 768 being the -default. For example, to set the receive trigger level to 512 bytes and the -transmit trigger level to 700 bytes, the insmod command would be: - -insmod esp rx_trigger=512 tx_trigger=700 - -The flow_off= and flow_on= options can be used to set the hardware flow off/ -flow on levels. The flow on level must be lower than the flow off level, and -the flow off level should be higher than rx_trigger. Valid values are 1 -through 1023, with 1016 being the default flow off level and 944 being the -default flow on level. For example, to set the flow off level to 1000 bytes -and the flow on level to 935 bytes, the insmod command would be: - -insmod esp flow_off=1000 flow_on=935 - -The rx_timeout= option can be used to set the receive timeout value. This -value indicates how long after receiving the last character that the ESP card -should wait before signalling an interrupt. Valid values are 0 though 255, -with 128 being the default. A value too high will increase latency, and a -value too low will cause unnecessary interrupts. For example, to set the -receive timeout to 255, the insmod command would be: - -insmod esp rx_timeout=255 - -The pio_threshold= option sets the threshold (in number of characters) for -using PIO mode instead of DMA mode. For example, if this value is 32, -transfers of 32 bytes or less will always use PIO mode. - -insmod esp pio_threshold=32 - -Multiple options can be listed on the insmod command line by separating each -option with a space. For example: - -insmod esp dma=3 trigger=512 - -The esp module can be automatically loaded when needed. To cause this to -happen, add the following lines to /etc/modprobe.conf (replacing the last line -with options for your configuration): - -alias char-major-57 esp -alias char-major-58 esp -options esp irq=0,0,0,0,0,0,3,0 divisor=0,0,0,0,0,0,0x4,0 - -You may also need to run 'depmod -a'. - -Devices must be created manually. To create the devices, note the output from -the module after it is inserted. The output will appear in the location where -kernel messages usually appear (usually /var/adm/messages). Create two devices -for each 'tty' mentioned, one with major of 57 and the other with major of 58. -The minor number should be the same as the tty number reported. The commands -would be (replace ? with the tty number): - -mknod /dev/ttyP? c 57 ? -mknod /dev/cup? c 58 ? - -For example, if the following line appears: - -Oct 24 18:17:23 techno kernel: ttyP8 at 0x0140 (irq = 3) is an ESP primary port - -...two devices should be created: - -mknod /dev/ttyP8 c 57 8 -mknod /dev/cup8 c 58 8 - -You may need to set the permissions on the devices: - -chmod 666 /dev/ttyP* -chmod 666 /dev/cup* - -The ESP module and the serial module should not conflict (they can be used at -the same time). After the ESP module has been loaded the ports on the ESP card -will no longer be accessible by the serial driver. - -If I/O errors are experienced when accessing the port, check for IRQ and DMA -conflicts ('cat /proc/interrupts' and 'cat /proc/dma' for a list of IRQs and -DMAs currently in use). - -Enjoy! -Andrew J. Robinson <arobinso@nyx.net> |