Based on kernel version 2.6.26. Page generated on 2008-07-16 21:13 EST.
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.