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NVMe: Implement doorbell stride capability

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The doorbell stride allows devices to spread out their doorbells instead
of packing them tightly.  This feature was added as part of ECN 003.

This patch also enables support for more than 512 queues :-)

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
This commit is contained in:
Matthew Wilcox 2011-10-20 17:00:41 -04:00
parent ce38c14957
commit f1938f6e1e
2 changed files with 15 additions and 3 deletions
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17
drivers/block/nvme.c
View file

@ -70,6 +70,7 @@ struct nvme_dev {
struct dma_pool *prp_small_pool;
int instance;
int queue_count;
int db_stride;
u32 ctrl_config;
struct msix_entry *entry;
struct nvme_bar __iomem *bar;
@ -672,7 +673,7 @@ static irqreturn_t nvme_process_cq(struct nvme_queue *nvmeq)
if (head == nvmeq->cq_head && phase == nvmeq->cq_phase)
return IRQ_NONE;
writel(head, nvmeq->q_db + 1);
writel(head, nvmeq->q_db + (1 << nvmeq->dev->db_stride));
nvmeq->cq_head = head;
nvmeq->cq_phase = phase;
@ -889,7 +890,7 @@ static struct nvme_queue *nvme_alloc_queue(struct nvme_dev *dev, int qid,
init_waitqueue_head(&nvmeq->sq_full);
init_waitqueue_entry(&nvmeq->sq_cong_wait, nvme_thread);
bio_list_init(&nvmeq->sq_cong);
nvmeq->q_db = &dev->dbs[qid * 2];
nvmeq->q_db = &dev->dbs[qid << (dev->db_stride + 1)];
nvmeq->q_depth = depth;
nvmeq->cq_vector = vector;
@ -981,6 +982,7 @@ static int __devinit nvme_configure_admin_queue(struct nvme_dev *dev)
cap = readq(&dev->bar->cap);
timeout = ((NVME_CAP_TIMEOUT(cap) + 1) * HZ / 2) + jiffies;
dev->db_stride = NVME_CAP_STRIDE(cap);
while (!(readl(&dev->bar->csts) & NVME_CSTS_RDY)) {
msleep(100);
@ -1357,7 +1359,7 @@ static int set_queue_count(struct nvme_dev *dev, int count)
static int __devinit nvme_setup_io_queues(struct nvme_dev *dev)
{
int result, cpu, i, nr_io_queues;
int result, cpu, i, nr_io_queues, db_bar_size;
nr_io_queues = num_online_cpus();
result = set_queue_count(dev, nr_io_queues);
@ -1369,6 +1371,15 @@ static int __devinit nvme_setup_io_queues(struct nvme_dev *dev)
/* Deregister the admin queue's interrupt */
free_irq(dev->entry[0].vector, dev->queues[0]);
db_bar_size = 4096 + ((nr_io_queues + 1) << (dev->db_stride + 3));
if (db_bar_size > 8192) {
iounmap(dev->bar);
dev->bar = ioremap(pci_resource_start(dev->pci_dev, 0),
db_bar_size);
dev->dbs = ((void __iomem *)dev->bar) + 4096;
dev->queues[0]->q_db = dev->dbs;
}
for (i = 0; i < nr_io_queues; i++)
dev->entry[i].entry = i;
for (;;) {

1
include/linux/nvme.h
View file

@ -36,6 +36,7 @@ struct nvme_bar {
};
#define NVME_CAP_TIMEOUT(cap) (((cap) >> 24) & 0xff)
#define NVME_CAP_STRIDE(cap) (((cap) >> 32) & 0xf)
enum {
NVME_CC_ENABLE = 1 << 0,