mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-25 13:43:55 +08:00
1da177e4c3
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!
155 lines
4.9 KiB
Plaintext
155 lines
4.9 KiB
Plaintext
General Description
|
|
===================
|
|
|
|
This driver supports the 53c700 and 53c700-66 chips. It also supports
|
|
the 53c710 but only in 53c700 emulation mode. It is full featured and
|
|
does sync (-66 and 710 only), disconnects and tag command queueing.
|
|
|
|
Since the 53c700 must be interfaced to a bus, you need to wrapper the
|
|
card detector around this driver. For an example, see the
|
|
NCR_D700.[ch] or lasi700.[ch] files.
|
|
|
|
The comments in the 53c700.[ch] files tell you which parts you need to
|
|
fill in to get the driver working.
|
|
|
|
|
|
Compile Time Flags
|
|
==================
|
|
|
|
The driver may be either io mapped or memory mapped. This is
|
|
selectable by configuration flags:
|
|
|
|
CONFIG_53C700_MEM_MAPPED
|
|
|
|
define if the driver is memory mapped.
|
|
|
|
CONFIG_53C700_IO_MAPPED
|
|
|
|
define if the driver is to be io mapped.
|
|
|
|
One or other of the above flags *must* be defined.
|
|
|
|
Other flags are:
|
|
|
|
CONFIG_53C700_LE_ON_BE
|
|
|
|
define if the chipset must be supported in little endian mode on a big
|
|
endian architecture (used for the 700 on parisc).
|
|
|
|
CONFIG_53C700_USE_CONSISTENT
|
|
|
|
allocate consistent memory (should only be used if your architecture
|
|
has a mixture of consistent and inconsistent memory). Fully
|
|
consistent or fully inconsistent architectures should not define this.
|
|
|
|
|
|
Using the Chip Core Driver
|
|
==========================
|
|
|
|
In order to plumb the 53c700 chip core driver into a working SCSI
|
|
driver, you need to know three things about the way the chip is wired
|
|
into your system (or expansion card).
|
|
|
|
1. The clock speed of the SCSI core
|
|
2. The interrupt line used
|
|
3. The memory (or io space) location of the 53c700 registers.
|
|
|
|
Optionally, you may also need to know other things, like how to read
|
|
the SCSI Id from the card bios or whether the chip is wired for
|
|
differential operation.
|
|
|
|
Usually you can find items 2. and 3. from general spec. documents or
|
|
even by examining the configuration of a working driver under another
|
|
operating system.
|
|
|
|
The clock speed is usually buried deep in the technical literature.
|
|
It is required because it is used to set up both the synchronous and
|
|
asynchronous dividers for the chip. As a general rule of thumb,
|
|
manufacturers set the clock speed at the lowest possible setting
|
|
consistent with the best operation of the chip (although some choose
|
|
to drive it off the CPU or bus clock rather than going to the expense
|
|
of an extra clock chip). The best operation clock speeds are:
|
|
|
|
53c700 - 25MHz
|
|
53c700-66 - 50MHz
|
|
53c710 - 40Mhz
|
|
|
|
Writing Your Glue Driver
|
|
========================
|
|
|
|
This will be a standard SCSI driver (I don't know of a good document
|
|
describing this, just copy from some other driver) with at least a
|
|
detect and release entry.
|
|
|
|
In the detect routine, you need to allocate a struct
|
|
NCR_700_Host_Parameters sized memory area and clear it (so that the
|
|
default values for everything are 0). Then you must fill in the
|
|
parameters that matter to you (see below), plumb the NCR_700_intr
|
|
routine into the interrupt line and call NCR_700_detect with the host
|
|
template and the new parameters as arguments. You should also call
|
|
the relevant request_*_region function and place the register base
|
|
address into the `base' pointer of the host parameters.
|
|
|
|
In the release routine, you must free the NCR_700_Host_Parameters that
|
|
you allocated, call the corresponding release_*_region and free the
|
|
interrupt.
|
|
|
|
Handling Interrupts
|
|
-------------------
|
|
|
|
In general, you should just plumb the card's interrupt line in with
|
|
|
|
request_irq(irq, NCR_700_intr, <irq flags>, <driver name>, host);
|
|
|
|
where host is the return from the relevant NCR_700_detect() routine.
|
|
|
|
You may also write your own interrupt handling routine which calls
|
|
NCR_700_intr() directly. However, you should only really do this if
|
|
you have a card with more than one chip on it and you can read a
|
|
register to tell which set of chips wants the interrupt.
|
|
|
|
Settable NCR_700_Host_Parameters
|
|
--------------------------------
|
|
|
|
The following are a list of the user settable parameters:
|
|
|
|
clock: (MANDATORY)
|
|
|
|
Set to the clock speed of the chip in MHz.
|
|
|
|
base: (MANDATORY)
|
|
|
|
set to the base of the io or mem region for the register set. On 64
|
|
bit architectures this is only 32 bits wide, so the registers must be
|
|
mapped into the low 32 bits of memory.
|
|
|
|
pci_dev: (OPTIONAL)
|
|
|
|
set to the PCI board device. Leave NULL for a non-pci board. This is
|
|
used for the pci_alloc_consistent() and pci_map_*() functions.
|
|
|
|
dmode_extra: (OPTIONAL, 53c710 only)
|
|
|
|
extra flags for the DMODE register. These are used to control bus
|
|
output pins on the 710. The settings should be a combination of
|
|
DMODE_FC1 and DMODE_FC2. What these pins actually do is entirely up
|
|
to the board designer. Usually it is safe to ignore this setting.
|
|
|
|
differential: (OPTIONAL)
|
|
|
|
set to 1 if the chip drives a differential bus.
|
|
|
|
force_le_on_be: (OPTIONAL, only if CONFIG_53C700_LE_ON_BE is set)
|
|
|
|
set to 1 if the chip is operating in little endian mode on a big
|
|
endian architecture.
|
|
|
|
chip710: (OPTIONAL)
|
|
|
|
set to 1 if the chip is a 53c710.
|
|
|
|
burst_disable: (OPTIONAL, 53c710 only)
|
|
|
|
disable 8 byte bursting for DMA transfers.
|
|
|