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authorMatthew R. Ochs <mrochs@linux.vnet.ibm.com>2018-03-26 11:30:22 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-08-03 07:50:41 +0200
commita5ed99bc6f59803e58b59bc1c84444f77b6b7712 (patch)
parentbb7cccb01c84e0b7c0a4d43fa7b25510e56e92df (diff)
scsi: cxlflash: Avoid clobbering context control register value
[ Upstream commit 465891fe9237b02f8d0fd26448f733fae7236f4a ] The SISLite specification originally defined the context control register with a single field of bits to represent the LISN and also stipulated that the register reset value be 0. The cxlflash driver took advantage of this when programming the LISN for the master contexts via an unconditional write - no other bits were preserved. When unmap support was added, SISLite was updated to define bit 0 of the context control register as a way for the AFU to notify the context owner that unmap operations were supported. Thus the assumptions under which the register is setup changed and the existing unconditional write is clobbering the unmap state for master contexts. This is presently not an issue due to the order in which the context control register is programmed in relation to the unmap bit being queried but should be addressed to avoid a future regression in the event this code is moved elsewhere. To remedy this issue, preserve the bits when programming the LISN field in the context control register. Since the LISN will now be programmed using a read value, assert that the initial state of the LISN field is as described in SISLite (0). Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com> Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2 files changed, 5 insertions, 1 deletions
diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index 12faf7f6c8ac..737314cac8d8 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -1303,7 +1303,10 @@ static void afu_err_intr_init(struct afu *afu)
for (i = 0; i < afu->num_hwqs; i++) {
hwq = get_hwq(afu, i);
- writeq_be(SISL_MSI_SYNC_ERROR, &hwq->host_map->ctx_ctrl);
+ reg = readq_be(&hwq->host_map->ctx_ctrl);
+ writeq_be(reg, &hwq->host_map->ctx_ctrl);
writeq_be(SISL_ISTATUS_MASK, &hwq->host_map->intr_mask);
diff --git a/drivers/scsi/cxlflash/sislite.h b/drivers/scsi/cxlflash/sislite.h
index 09daa86670fc..0892fb1f0a1e 100644
--- a/drivers/scsi/cxlflash/sislite.h
+++ b/drivers/scsi/cxlflash/sislite.h
@@ -284,6 +284,7 @@ struct sisl_host_map {
__be64 cmd_room;
__be64 ctx_ctrl; /* least significant byte or b56:63 is LISN# */
#define SISL_CTX_CTRL_UNMAP_SECTOR 0x8000000000000000ULL /* b0 */
__be64 mbox_w; /* restricted use */
__be64 sq_start; /* Submission Queue (R/W): write sequence and */
__be64 sq_end; /* inclusion semantics are the same as RRQ */