[PATCH 0/1] nvme: disable CC.CRIME (NVME_CC_CRIME)

[PATCH 0/1] nvme: disable CC.CRIME (NVME_CC_CRIME)

[gjoyce]

From: Greg Joyce <gjoyce@linux.ibm.com>

NVMe 2.0 introduced a configuration setting CC.CRIME that allows the 
controller to set CSTS.RDY before the media is fully enabled. In this
case commands listed in Figure 103 may return the status
NVME_SC_ADMIN_COMMAND_MEDIA_NOT_READY. The NVMe driver is not coded
to handle these failures so initialization errors occur.

Since the current driver does not:
	1) retry media not ready errors
	2) utilize any parallel initialization that CRIME may provide

setting NVME_CC_CRIME provides no value.

The NVMe 2.0 spec says this about CC.CRIME:
	"If the CAP.CRMS field is set to 11b, then both controller
	 ready modes are supported, and the host may select the
	 controller ready mode by modifying the value of the
	 CC.CRIME bit."

This the CC.CRIME feature is optional and this patch removes it.


Greg Joyce (1):
  nvme: disable CC.CRIME (NVME_CC_CRIME)

 drivers/nvme/host/core.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

-- 
gjoyce@linux.ibm.com

[PATCH 1/1] nvme: disable CC.CRIME (NVME_CC_CRIME)

[gjoyce]

From: Greg Joyce <gjoyce@linux.ibm.com>

Disable NVME_CC_CRIME so that CSTS.RDY indicates that the media
is ready and able to handle commands without returning
NVME_SC_ADMIN_COMMAND_MEDIA_NOT_READY.

Signed-off-by: Greg Joyce <gjoyce@linux.ibm.com>
---
 drivers/nvme/host/core.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index ba6508455e18..6b313524143a 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2458,8 +2458,13 @@ int nvme_enable_ctrl(struct nvme_ctrl *ctrl)
 	else
 		ctrl->ctrl_config = NVME_CC_CSS_NVM;
 
-	if (ctrl->cap & NVME_CAP_CRMS_CRWMS && ctrl->cap & NVME_CAP_CRMS_CRIMS)
-		ctrl->ctrl_config |= NVME_CC_CRIME;
+	/*
+	 * Setting CRIME results in CSTS.RDY before the media is ready. This
+	 * make it possible for media related commands to return the error
+	 * NVME_SC_ADMIN_COMMAND_MEDIA_NOT_READY. Until the driver is
+	 * structured to handle retries, disable CC.CRIME.
+	 */
+	ctrl->ctrl_config &= ~NVME_CC_CRIME;
 
 	ctrl->ctrl_config |= (NVME_CTRL_PAGE_SHIFT - 12) << NVME_CC_MPS_SHIFT;
 	ctrl->ctrl_config |= NVME_CC_AMS_RR | NVME_CC_SHN_NONE;
-- 
gjoyce@linux.ibm.com

Re: [PATCH 1/1] nvme: disable CC.CRIME (NVME_CC_CRIME)

[Keith Busch]

On Mon, Oct 07, 2024 at 09:59:58AM -0500, gjoyce@linux.ibm.com wrote:
> @@ -2458,8 +2458,13 @@ int nvme_enable_ctrl(struct nvme_ctrl *ctrl)
>  	else
>  		ctrl->ctrl_config = NVME_CC_CSS_NVM;
>  
> -	if (ctrl->cap & NVME_CAP_CRMS_CRWMS && ctrl->cap & NVME_CAP_CRMS_CRIMS)
> -		ctrl->ctrl_config |= NVME_CC_CRIME;
> +	/*
> +	 * Setting CRIME results in CSTS.RDY before the media is ready. This
> +	 * make it possible for media related commands to return the error
> +	 * NVME_SC_ADMIN_COMMAND_MEDIA_NOT_READY. Until the driver is
> +	 * structured to handle retries, disable CC.CRIME.
> +	 */
> +	ctrl->ctrl_config &= ~NVME_CC_CRIME;

A little further down in this function, there's a check from CC_CRIME to
know which ready timeout value to use. You can remove that check with
this change.