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Subject[PATCH 2/3] nvme: Retrieve the required IO queue entry size from the controller
Date
On PCIe based NVME devices, this will  retrieve the IO queue entry
size from the controller and use the "required" setting.

It should always be 6 (64 bytes) by spec. However some controllers
such as Apple's are not properly implementing the spec and require
the size to be 7 (128 bytes).

This provides the ground work for the subsequent quirks for these
controllers.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
drivers/nvme/host/core.c | 25 +++++++++++++++++++++++++
drivers/nvme/host/nvme.h | 1 +
drivers/nvme/host/pci.c | 9 ++++++---
include/linux/nvme.h | 1 +
4 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index cc09b81fc7f4..716ebe87a2b8 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1986,6 +1986,7 @@ int nvme_enable_ctrl(struct nvme_ctrl *ctrl, u64 cap)
ctrl->ctrl_config = NVME_CC_CSS_NVM;
ctrl->ctrl_config |= (page_shift - 12) << NVME_CC_MPS_SHIFT;
ctrl->ctrl_config |= NVME_CC_AMS_RR | NVME_CC_SHN_NONE;
+ /* Use default IOSQES. We'll update it later if needed */
ctrl->ctrl_config |= NVME_CC_IOSQES | NVME_CC_IOCQES;
ctrl->ctrl_config |= NVME_CC_ENABLE;

@@ -2698,6 +2699,30 @@ int nvme_init_identify(struct nvme_ctrl *ctrl)
ctrl->hmmin = le32_to_cpu(id->hmmin);
ctrl->hmminds = le32_to_cpu(id->hmminds);
ctrl->hmmaxd = le16_to_cpu(id->hmmaxd);
+
+ /* Grab required IO queue size */
+ ctrl->iosqes = id->sqes & 0xf;
+ if (ctrl->iosqes < NVME_NVM_IOSQES) {
+ dev_err(ctrl->device,
+ "unsupported required IO queue size %d\n", ctrl->iosqes);
+ ret = -EINVAL;
+ goto out_free;
+ }
+ /*
+ * If our IO queue size isn't the default, update the setting
+ * in CC:IOSQES.
+ */
+ if (ctrl->iosqes != NVME_NVM_IOSQES) {
+ ctrl->ctrl_config &= ~(0xfu << NVME_CC_IOSQES_SHIFT);
+ ctrl->ctrl_config |= ctrl->iosqes << NVME_CC_IOSQES_SHIFT;
+ ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC,
+ ctrl->ctrl_config);
+ if (ret) {
+ dev_err(ctrl->device,
+ "error updating CC register\n");
+ goto out_free;
+ }
+ }
}

ret = nvme_mpath_init(ctrl, id);
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 716a876119c8..34ef35fcd8a5 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -244,6 +244,7 @@ struct nvme_ctrl {
u32 hmmin;
u32 hmminds;
u16 hmmaxd;
+ u8 iosqes;

/* Fabrics only */
u16 sqsize;
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 8f006638452b..54b35ea4af88 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -28,7 +28,7 @@
#include "trace.h"
#include "nvme.h"

-#define SQ_SIZE(q) ((q)->q_depth * sizeof(struct nvme_command))
+#define SQ_SIZE(q) ((q)->q_depth << (q)->sqes)
#define CQ_SIZE(q) ((q)->q_depth * sizeof(struct nvme_completion))

#define SGES_PER_PAGE (PAGE_SIZE / sizeof(struct nvme_sgl_desc))
@@ -162,7 +162,7 @@ static inline struct nvme_dev *to_nvme_dev(struct nvme_ctrl *ctrl)
struct nvme_queue {
struct nvme_dev *dev;
spinlock_t sq_lock;
- struct nvme_command *sq_cmds;
+ void *sq_cmds;
/* only used for poll queues: */
spinlock_t cq_poll_lock ____cacheline_aligned_in_smp;
volatile struct nvme_completion *cqes;
@@ -178,6 +178,7 @@ struct nvme_queue {
u16 last_cq_head;
u16 qid;
u8 cq_phase;
+ u8 sqes;
unsigned long flags;
#define NVMEQ_ENABLED 0
#define NVMEQ_SQ_CMB 1
@@ -488,7 +489,8 @@ static void nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd,
bool write_sq)
{
spin_lock(&nvmeq->sq_lock);
- memcpy(&nvmeq->sq_cmds[nvmeq->sq_tail], cmd, sizeof(*cmd));
+ memcpy(nvmeq->sq_cmds + (nvmeq->sq_tail << nvmeq->sqes),
+ cmd, sizeof(*cmd));
if (++nvmeq->sq_tail == nvmeq->q_depth)
nvmeq->sq_tail = 0;
nvme_write_sq_db(nvmeq, write_sq);
@@ -1465,6 +1467,7 @@ static int nvme_alloc_queue(struct nvme_dev *dev, int qid, int depth)
if (dev->ctrl.queue_count > qid)
return 0;

+ nvmeq->sqes = qid ? dev->ctrl.iosqes : NVME_NVM_ADMSQES;
nvmeq->q_depth = depth;
nvmeq->cqes = dma_alloc_coherent(dev->dev, CQ_SIZE(nvmeq),
&nvmeq->cq_dma_addr, GFP_KERNEL);
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 01aa6a6c241d..7af18965fb57 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -141,6 +141,7 @@ enum {
* (In bytes and specified as a power of two (2^n)).
*/
#define NVME_NVM_IOSQES 6
+#define NVME_NVM_ADMSQES 6
#define NVME_NVM_IOCQES 4

enum {
--
2.17.1
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