scsi: cxlflash: Improve context_reset() logic (3d2f617d) · Commits · 戴 / test

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 <ukrishn@linux.vnet.ibm.com> Acked-by:

Matthew R. Ochs <mrochs@linux.vnet.ibm.com> Signed-off-by:

Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/cxlflash/main.c

+5 −18

Original line number	Diff line number	Diff line
		@@ -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 @@ write_rrin:
		/* 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);
		}

		/**

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