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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 | |
155 |
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