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From: Stephen M. Cameron on 19 Jul 2010 14:50
From: Stephen M. Cameron <scameron(a)beardog.cce.hp.com>

cciss: factor out cciss_enter_performant_mode

Signed-off-by: Stephen M. Cameron <scameron(a)beardog.cce.hp.com>
---
drivers/block/cciss.c | 98 ++++++++++++++++++++++++++++++-------------------
1 files changed, 59 insertions(+), 39 deletions(-)

diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index ee7cfde..17e420c 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -3830,54 +3830,36 @@ static void __devinit cciss_wait_for_mode_change_ack(ctlr_info_t *h)
}
}

-static void __devinit cciss_put_controller_into_performant_mode(ctlr_info_t *h)
+static __devinit void cciss_enter_performant_mode(ctlr_info_t *h)
{
- __u32 trans_support;
+ /* This is a bit complicated. There are 8 registers on
+ * the controller which we write to to tell it 8 different
+ * sizes of commands which there may be. It's a way of
+ * reducing the DMA done to fetch each command. Encoded into
+ * each command's tag are 3 bits which communicate to the controller
+ * which of the eight sizes that command fits within. The size of
+ * each command depends on how many scatter gather entries there are.
+ * Each SG entry requires 16 bytes. The eight registers are programmed
+ * with the number of 16-byte blocks a command of that size requires.
+ * The smallest command possible requires 5 such 16 byte blocks.
+ * the largest command possible requires MAXSGENTRIES + 4 16-byte
+ * blocks. Note, this only extends to the SG entries contained
+ * within the command block, and does not extend to chained blocks
+ * of SG elements. bft[] contains the eight values we write to
+ * the registers. They are not evenly distributed, but have more
+ * sizes for small commands, and fewer sizes for larger commands.
+ */
__u32 trans_offset;
+ int bft[8] = { 5, 6, 8, 10, 12, 20, 28, MAXSGENTRIES + 4};
/*
* 5 = 1 s/g entry or 4k
* 6 = 2 s/g entry or 8k
* 8 = 4 s/g entry or 16k
* 10 = 6 s/g entry or 24k
*/
- int bft[8] = { 5, 6, 8, 10, 12, 20, 28, MAXSGENTRIES + 4};
unsigned long register_value;
-
BUILD_BUG_ON(28 > MAXSGENTRIES + 4);

- dev_dbg(&h->pdev->dev, "Trying to put board into Performant mode\n");
- /* Attempt to put controller into performant mode if supported */
- /* Does board support performant mode? */
- trans_support = readl(&(h->cfgtable->TransportSupport));
- if (!(trans_support & PERFORMANT_MODE))
- return;
-
- printk(KERN_WARNING "cciss%d: Placing controller into "
- "performant mode\n", h->ctlr);
- /* Performant mode demands commands on a 32 byte boundary
- * pci_alloc_consistent aligns on page boundarys already.
- * Just need to check if divisible by 32
- */
- if ((sizeof(CommandList_struct) % 32) != 0) {
- printk(KERN_WARNING "%s %d %s\n",
- "cciss info: command size[",
- (int)sizeof(CommandList_struct),
- "] not divisible by 32, no performant mode..\n");
- return;
- }
-
- /* Performant mode ring buffer and supporting data structures */
- h->reply_pool = (__u64 *)pci_alloc_consistent(
- h->pdev, h->max_commands * sizeof(__u64),
- &(h->reply_pool_dhandle));
-
- /* Need a block fetch table for performant mode */
- h->blockFetchTable = kmalloc(((h->maxsgentries+1) *
- sizeof(__u32)), GFP_KERNEL);
-
- if ((h->reply_pool == NULL) || (h->blockFetchTable == NULL))
- goto clean_up;
-
h->reply_pool_wraparound = 1; /* spec: init to 1 */

/* Controller spec: zero out this buffer. */
@@ -3906,18 +3888,56 @@ static void __devinit cciss_put_controller_into_performant_mode(ctlr_info_t *h)
writel(CFGTBL_Trans_Performant,
&(h->cfgtable->HostWrite.TransportRequest));

- h->transMethod = CFGTBL_Trans_Performant;
writel(CFGTBL_ChangeReq, h->vaddr + SA5_DOORBELL);
cciss_wait_for_mode_change_ack(h);
register_value = readl(&(h->cfgtable->TransportActive));
- if (!(register_value & CFGTBL_Trans_Performant)) {
+ if (!(register_value & CFGTBL_Trans_Performant))
printk(KERN_WARNING "cciss: unable to get board into"
" performant mode\n");
+}
+
+static void __devinit cciss_put_controller_into_performant_mode(ctlr_info_t *h)
+{
+ __u32 trans_support;
+
+ dev_dbg(&h->pdev->dev, "Trying to put board into Performant mode\n");
+ /* Attempt to put controller into performant mode if supported */
+ /* Does board support performant mode? */
+ trans_support = readl(&(h->cfgtable->TransportSupport));
+ if (!(trans_support & PERFORMANT_MODE))
+ return;
+
+ printk(KERN_WARNING "cciss%d: Placing controller into "
+ "performant mode\n", h->ctlr);
+ /* Performant mode demands commands on a 32 byte boundary
+ * pci_alloc_consistent aligns on page boundarys already.
+ * Just need to check if divisible by 32
+ */
+ if ((sizeof(CommandList_struct) % 32) != 0) {
+ printk(KERN_WARNING "%s %d %s\n",
+ "cciss info: command size[",
+ (int)sizeof(CommandList_struct),
+ "] not divisible by 32, no performant mode..\n");
return;
}

+ /* Performant mode ring buffer and supporting data structures */
+ h->reply_pool = (__u64 *)pci_alloc_consistent(
+ h->pdev, h->max_commands * sizeof(__u64),
+ &(h->reply_pool_dhandle));
+
+ /* Need a block fetch table for performant mode */
+ h->blockFetchTable = kmalloc(((h->maxsgentries+1) *
+ sizeof(__u32)), GFP_KERNEL);
+
+ if ((h->reply_pool == NULL) || (h->blockFetchTable == NULL))
+ goto clean_up;
+
+ cciss_enter_performant_mode(h);
+
/* Change the access methods to the performant access methods */
h->access = SA5_performant_access;
+ h->transMethod = CFGTBL_Trans_Performant;

return;
clean_up:

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Prev: [PATCH 24/26] cciss: separate cmd_alloc() and cmd_special_alloc()
Next: [PATCH 22/26] cciss: forbid hard reset of 640x boards