diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/block/cciss.c | 52 |
1 files changed, 25 insertions, 27 deletions
diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c index b7024711060..97feb50675c 100644 --- a/drivers/block/cciss.c +++ b/drivers/block/cciss.c @@ -4072,6 +4072,30 @@ static int __devinit cciss_find_cfgtables(ctlr_info_t *h) return 0; } +/* Interrogate the hardware for some limits: + * max commands, max SG elements without chaining, and with chaining, + * SG chain block size, etc. + */ +static void __devinit cciss_find_board_params(ctlr_info_t *h) +{ + h->max_commands = readl(&(h->cfgtable->MaxPerformantModeCommands)); + h->nr_cmds = h->max_commands - 4; /* Allow room for some ioctls */ + h->maxsgentries = readl(&(h->cfgtable->MaxSGElements)); + /* + * Limit in-command s/g elements to 32 save dma'able memory. + * Howvever spec says if 0, use 31 + */ + h->max_cmd_sgentries = 31; + if (h->maxsgentries > 512) { + h->max_cmd_sgentries = 32; + h->chainsize = h->maxsgentries - h->max_cmd_sgentries + 1; + h->maxsgentries--; /* save one for chain pointer */ + } else { + h->maxsgentries = 31; /* default to traditional values */ + h->chainsize = 0; + } +} + static int __devinit cciss_pci_init(ctlr_info_t *c) { int prod_index, err; @@ -4127,34 +4151,8 @@ static int __devinit cciss_pci_init(ctlr_info_t *c) #ifdef CCISS_DEBUG print_cfg_table(c->cfgtable); #endif /* CCISS_DEBUG */ + cciss_find_board_params(c); - /* Some controllers support Zero Memory Raid (ZMR). - * When configured in ZMR mode the number of supported - * commands drops to 64. So instead of just setting an - * arbitrary value we make the driver a little smarter. - * We read the config table to tell us how many commands - * are supported on the controller then subtract 4 to - * leave a little room for ioctl calls. - */ - c->max_commands = readl(&(c->cfgtable->MaxPerformantModeCommands)); - c->maxsgentries = readl(&(c->cfgtable->MaxSGElements)); - - /* - * Limit native command to 32 s/g elements to save dma'able memory. - * Howvever spec says if 0, use 31 - */ - - c->max_cmd_sgentries = 31; - if (c->maxsgentries > 512) { - c->max_cmd_sgentries = 32; - c->chainsize = c->maxsgentries - c->max_cmd_sgentries + 1; - c->maxsgentries -= 1; /* account for chain pointer */ - } else { - c->maxsgentries = 31; /* Default to traditional value */ - c->chainsize = 0; /* traditional */ - } - - c->nr_cmds = c->max_commands - 4; if ((readb(&c->cfgtable->Signature[0]) != 'C') || (readb(&c->cfgtable->Signature[1]) != 'I') || (readb(&c->cfgtable->Signature[2]) != 'S') || |