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James" Subject: [PATCH linux dev-4.10 3/3] drivers: fsi: sbefifo: Attempt reset request during probe Date: Tue, 17 Oct 2017 16:35:53 -0500 X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1508276153-3779-1-git-send-email-eajames@linux.vnet.ibm.com> References: <1508276153-3779-1-git-send-email-eajames@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17101721-0016-0000-0000-000007AC0B49 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007908; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000237; SDB=6.00932594; UDB=6.00469652; IPR=6.00712884; BA=6.00005643; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00017581; XFM=3.00000015; UTC=2017-10-17 21:36:03 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17101721-0017-0000-0000-00003BE63503 Message-Id: <1508276153-3779-4-git-send-email-eajames@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-10-17_14:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1710170300 X-BeenThere: openbmc@lists.ozlabs.org X-Mailman-Version: 2.1.24 Precedence: list List-Id: Development list for OpenBMC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 17 Oct 2017 21:36:07 -0000 From: "Edward A. James" If data is found in the FIFO, the driver currently immediately fails the probe. Instead, try a reset request and poll for it's completion for a while (this protocol is defined in the SBE FIFO spec, though the timeout lengths are my own invention). Signed-off-by: Edward A. James --- drivers/fsi/fsi-sbefifo.c | 53 +++++++++++++++++++++++++++++++++++++---------- 1 file changed, 42 insertions(+), 11 deletions(-) diff --git a/drivers/fsi/fsi-sbefifo.c b/drivers/fsi/fsi-sbefifo.c index 764d8f3..f756822 100644 --- a/drivers/fsi/fsi-sbefifo.c +++ b/drivers/fsi/fsi-sbefifo.c @@ -47,8 +47,10 @@ #define SBEFIFO_STS 0x04 #define SBEFIFO_EMPTY BIT(20) +#define SBEFIFO_STS_RESET_REQ BIT(25) #define SBEFIFO_EOT_RAISE 0x08 #define SBEFIFO_EOT_MAGIC 0xffffffff +#define SBEFIFO_REQ_RESET 0x0C #define SBEFIFO_EOT_ACK 0x14 #define SBEFIFO_RESCHEDULE msecs_to_jiffies(500) @@ -831,6 +833,36 @@ static int sbefifo_unregister_child(struct device *dev, void *data) return 0; } +static int sbefifo_request_reset(struct sbefifo *sbefifo) +{ + int ret; + u32 status; + unsigned long start; + const unsigned int wait_time = 5; /* jiffies */ + const unsigned long timeout = msecs_to_jiffies(250); + + ret = sbefifo_outw(sbefifo, SBEFIFO_UP | SBEFIFO_REQ_RESET, 1); + if (ret) + return ret; + + start = jiffies; + + do { + ret = sbefifo_inw(sbefifo, SBEFIFO_UP | SBEFIFO_STS, &status); + if (ret) + return ret; + + if (!(status & SBEFIFO_STS_RESET_REQ)) + return 0; + + set_current_state(TASK_INTERRUPTIBLE); + if (schedule_timeout(wait_time) > 0) + return -EINTR; + } while (time_after(start + timeout, jiffies)); + + return -ETIME; +} + static int sbefifo_probe(struct device *dev) { struct fsi_device *fsi_dev = to_fsi_dev(dev); @@ -838,7 +870,7 @@ static int sbefifo_probe(struct device *dev) struct device_node *np; struct platform_device *child; char child_name[32]; - u32 sts; + u32 up, down; int ret, child_idx = 0; dev_dbg(dev, "Found sbefifo device\n"); @@ -848,22 +880,21 @@ static int sbefifo_probe(struct device *dev) sbefifo->fsi_dev = fsi_dev; - ret = sbefifo_inw(sbefifo, SBEFIFO_UP | SBEFIFO_STS, &sts); + ret = sbefifo_inw(sbefifo, SBEFIFO_UP | SBEFIFO_STS, &up); if (ret) return ret; - if (!(sts & SBEFIFO_EMPTY)) { - dev_err(dev, "Found data in upstream fifo\n"); - return -EIO; - } - - ret = sbefifo_inw(sbefifo, SBEFIFO_DWN | SBEFIFO_STS, &sts); + ret = sbefifo_inw(sbefifo, SBEFIFO_DWN | SBEFIFO_STS, &down); if (ret) return ret; - if (!(sts & SBEFIFO_EMPTY)) { - dev_err(dev, "Found data in downstream fifo\n"); - return -EIO; + if (!(up & SBEFIFO_EMPTY) || !(down & SBEFIFO_EMPTY)) { + ret = sbefifo_request_reset(sbefifo); + if (ret) { + dev_err(dev, + "fifos weren't empty and failed the reset\n"); + return ret; + } } spin_lock_init(&sbefifo->lock); -- 1.8.3.1