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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/scsi/53c700.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!
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-rw-r--r-- | Documentation/scsi/53c700.txt | 154 |
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1 | General Description | ||
2 | =================== | ||
3 | |||
4 | This driver supports the 53c700 and 53c700-66 chips. It also supports | ||
5 | the 53c710 but only in 53c700 emulation mode. It is full featured and | ||
6 | does sync (-66 and 710 only), disconnects and tag command queueing. | ||
7 | |||
8 | Since the 53c700 must be interfaced to a bus, you need to wrapper the | ||
9 | card detector around this driver. For an example, see the | ||
10 | NCR_D700.[ch] or lasi700.[ch] files. | ||
11 | |||
12 | The comments in the 53c700.[ch] files tell you which parts you need to | ||
13 | fill in to get the driver working. | ||
14 | |||
15 | |||
16 | Compile Time Flags | ||
17 | ================== | ||
18 | |||
19 | The driver may be either io mapped or memory mapped. This is | ||
20 | selectable by configuration flags: | ||
21 | |||
22 | CONFIG_53C700_MEM_MAPPED | ||
23 | |||
24 | define if the driver is memory mapped. | ||
25 | |||
26 | CONFIG_53C700_IO_MAPPED | ||
27 | |||
28 | define if the driver is to be io mapped. | ||
29 | |||
30 | One or other of the above flags *must* be defined. | ||
31 | |||
32 | Other flags are: | ||
33 | |||
34 | CONFIG_53C700_LE_ON_BE | ||
35 | |||
36 | define if the chipset must be supported in little endian mode on a big | ||
37 | endian architecture (used for the 700 on parisc). | ||
38 | |||
39 | CONFIG_53C700_USE_CONSISTENT | ||
40 | |||
41 | allocate consistent memory (should only be used if your architecture | ||
42 | has a mixture of consistent and inconsistent memory). Fully | ||
43 | consistent or fully inconsistent architectures should not define this. | ||
44 | |||
45 | |||
46 | Using the Chip Core Driver | ||
47 | ========================== | ||
48 | |||
49 | In order to plumb the 53c700 chip core driver into a working SCSI | ||
50 | driver, you need to know three things about the way the chip is wired | ||
51 | into your system (or expansion card). | ||
52 | |||
53 | 1. The clock speed of the SCSI core | ||
54 | 2. The interrupt line used | ||
55 | 3. The memory (or io space) location of the 53c700 registers. | ||
56 | |||
57 | Optionally, you may also need to know other things, like how to read | ||
58 | the SCSI Id from the card bios or whether the chip is wired for | ||
59 | differential operation. | ||
60 | |||
61 | Usually you can find items 2. and 3. from general spec. documents or | ||
62 | even by examining the configuration of a working driver under another | ||
63 | operating system. | ||
64 | |||
65 | The clock speed is usually buried deep in the technical literature. | ||
66 | It is required because it is used to set up both the synchronous and | ||
67 | asynchronous dividers for the chip. As a general rule of thumb, | ||
68 | manufacturers set the clock speed at the lowest possible setting | ||
69 | consistent with the best operation of the chip (although some choose | ||
70 | to drive it off the CPU or bus clock rather than going to the expense | ||
71 | of an extra clock chip). The best operation clock speeds are: | ||
72 | |||
73 | 53c700 - 25MHz | ||
74 | 53c700-66 - 50MHz | ||
75 | 53c710 - 40Mhz | ||
76 | |||
77 | Writing Your Glue Driver | ||
78 | ======================== | ||
79 | |||
80 | This will be a standard SCSI driver (I don't know of a good document | ||
81 | describing this, just copy from some other driver) with at least a | ||
82 | detect and release entry. | ||
83 | |||
84 | In the detect routine, you need to allocate a struct | ||
85 | NCR_700_Host_Parameters sized memory area and clear it (so that the | ||
86 | default values for everything are 0). Then you must fill in the | ||
87 | parameters that matter to you (see below), plumb the NCR_700_intr | ||
88 | routine into the interrupt line and call NCR_700_detect with the host | ||
89 | template and the new parameters as arguments. You should also call | ||
90 | the relevant request_*_region function and place the register base | ||
91 | address into the `base' pointer of the host parameters. | ||
92 | |||
93 | In the release routine, you must free the NCR_700_Host_Parameters that | ||
94 | you allocated, call the corresponding release_*_region and free the | ||
95 | interrupt. | ||
96 | |||
97 | Handling Interrupts | ||
98 | ------------------- | ||
99 | |||
100 | In general, you should just plumb the card's interrupt line in with | ||
101 | |||
102 | request_irq(irq, NCR_700_intr, <irq flags>, <driver name>, host); | ||
103 | |||
104 | where host is the return from the relevant NCR_700_detect() routine. | ||
105 | |||
106 | You may also write your own interrupt handling routine which calls | ||
107 | NCR_700_intr() directly. However, you should only really do this if | ||
108 | you have a card with more than one chip on it and you can read a | ||
109 | register to tell which set of chips wants the interrupt. | ||
110 | |||
111 | Settable NCR_700_Host_Parameters | ||
112 | -------------------------------- | ||
113 | |||
114 | The following are a list of the user settable parameters: | ||
115 | |||
116 | clock: (MANDATORY) | ||
117 | |||
118 | Set to the clock speed of the chip in MHz. | ||
119 | |||
120 | base: (MANDATORY) | ||
121 | |||
122 | set to the base of the io or mem region for the register set. On 64 | ||
123 | bit architectures this is only 32 bits wide, so the registers must be | ||
124 | mapped into the low 32 bits of memory. | ||
125 | |||
126 | pci_dev: (OPTIONAL) | ||
127 | |||
128 | set to the PCI board device. Leave NULL for a non-pci board. This is | ||
129 | used for the pci_alloc_consistent() and pci_map_*() functions. | ||
130 | |||
131 | dmode_extra: (OPTIONAL, 53c710 only) | ||
132 | |||
133 | extra flags for the DMODE register. These are used to control bus | ||
134 | output pins on the 710. The settings should be a combination of | ||
135 | DMODE_FC1 and DMODE_FC2. What these pins actually do is entirely up | ||
136 | to the board designer. Usually it is safe to ignore this setting. | ||
137 | |||
138 | differential: (OPTIONAL) | ||
139 | |||
140 | set to 1 if the chip drives a differential bus. | ||
141 | |||
142 | force_le_on_be: (OPTIONAL, only if CONFIG_53C700_LE_ON_BE is set) | ||
143 | |||
144 | set to 1 if the chip is operating in little endian mode on a big | ||
145 | endian architecture. | ||
146 | |||
147 | chip710: (OPTIONAL) | ||
148 | |||
149 | set to 1 if the chip is a 53c710. | ||
150 | |||
151 | burst_disable: (OPTIONAL, 53c710 only) | ||
152 | |||
153 | disable 8 byte bursting for DMA transfers. | ||
154 | |||