From mboxrd@z Thu Jan 1 00:00:00 1970 From: Uma Krishnan Subject: [PATCH v2 03/14] cxlflash: Improve context_reset() logic Date: Mon, 28 Nov 2016 18:41:36 -0600 Message-ID: <1480380096-60274-1-git-send-email-ukrishn@linux.vnet.ibm.com> References: <1480379984-60114-1-git-send-email-ukrishn@linux.vnet.ibm.com> Return-path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:43552 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753935AbcK2Al5 (ORCPT ); Mon, 28 Nov 2016 19:41:57 -0500 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uAT0cWE3043134 for ; Mon, 28 Nov 2016 19:41:47 -0500 Received: from e35.co.us.ibm.com (e35.co.us.ibm.com [32.97.110.153]) by mx0a-001b2d01.pphosted.com with ESMTP id 270xutseqm-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 28 Nov 2016 19:41:46 -0500 Received: from localhost by e35.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 28 Nov 2016 17:41:46 -0700 In-Reply-To: <1480379984-60114-1-git-send-email-ukrishn@linux.vnet.ibm.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: linux-scsi@vger.kernel.org, James Bottomley , "Martin K. Petersen" , "Matthew R. Ochs" , "Manoj N. Kumar" Cc: Brian King , linuxppc-dev@lists.ozlabs.org, Ian Munsie , Andrew Donnellan , Frederic Barrat , Christophe Lombard Currently, the context reset routine waits for command room to be available before sending the reset request. Per review of the SISLite specification and clarifications from the CXL Flash AFU designers, this wait is unnecessary. The reset request can be sent anytime regardless of command room, so long as only a single reset request is active at any one point in time. This commit simplifies the reset routine by removing the wait for command room. Additionally it adds a debug trace to help pinpoint hardware errors when a context reset does not complete. Signed-off-by: Uma Krishnan Acked-by: Matthew R. Ochs --- drivers/scsi/cxlflash/main.c | 23 +++++------------------ 1 file changed, 5 insertions(+), 18 deletions(-) diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c index 6004860..6d33d8c 100644 --- a/drivers/scsi/cxlflash/main.c +++ b/drivers/scsi/cxlflash/main.c @@ -263,8 +263,9 @@ static void context_reset(struct afu_cmd *cmd) { int nretry = 0; u64 rrin = 0x1; - u64 room = 0; struct afu *afu = cmd->parent; + struct cxlflash_cfg *cfg = afu->parent; + struct device *dev = &cfg->dev->dev; ulong lock_flags; pr_debug("%s: cmd=%p\n", __func__, cmd); @@ -280,23 +281,6 @@ static void context_reset(struct afu_cmd *cmd) cmd->sa.host_use_b[0] |= (B_DONE | B_ERROR | B_TIMEOUT); spin_unlock_irqrestore(&cmd->slock, lock_flags); - /* - * We really want to send this reset at all costs, so spread - * out wait time on successive retries for available room. - */ - do { - room = readq_be(&afu->host_map->cmd_room); - atomic64_set(&afu->room, room); - if (room) - goto write_rrin; - udelay(1 << nretry); - } while (nretry++ < MC_ROOM_RETRY_CNT); - - pr_err("%s: no cmd_room to send reset\n", __func__); - return; - -write_rrin: - nretry = 0; writeq_be(rrin, &afu->host_map->ioarrin); do { rrin = readq_be(&afu->host_map->ioarrin); @@ -305,6 +289,9 @@ static void context_reset(struct afu_cmd *cmd) /* Double delay each time */ udelay(1 << nretry); } while (nretry++ < MC_ROOM_RETRY_CNT); + + dev_dbg(dev, "%s: returning rrin=0x%016llX nretry=%d\n", + __func__, rrin, nretry); } /** -- 2.1.0