From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751551AbeFDTCB (ORCPT ); Mon, 4 Jun 2018 15:02:01 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:57204 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751355AbeFDTBJ (ORCPT ); Mon, 4 Jun 2018 15:01:09 -0400 From: Eddie James To: linux-i2c@vger.kernel.org Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, wsa@the-dreams.de, robh+dt@kernel.org, benh@kernel.crashing.org, joel@jms.id.au, mark.rutland@arm.com, gregkh@linuxfoundation.org, rdunlap@infradead.org, andy.shevchenko@gmail.com, Eddie James Subject: [PATCH v9 4/7] i2c: fsi: Add abort and hardware reset procedures Date: Mon, 4 Jun 2018 14:00:47 -0500 X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1528138850-18259-1-git-send-email-eajames@linux.vnet.ibm.com> References: <1528138850-18259-1-git-send-email-eajames@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18060419-0052-0000-0000-000002F81614 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009129; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000265; SDB=6.01042302; UDB=6.00533708; IPR=6.00821432; MB=3.00021461; MTD=3.00000008; XFM=3.00000015; UTC=2018-06-04 19:01:06 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18060419-0053-0000-0000-00005CE46DA4 Message-Id: <1528138850-18259-5-git-send-email-eajames@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-06-04_13:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1805220000 definitions=main-1806040219 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add abort procedure for failed transfers. Add engine and bus reset procedures to recover from as many faults as possible. Signed-off-by: Eddie James --- drivers/i2c/busses/i2c-fsi.c | 179 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 179 insertions(+) diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c index 12130c3..101b9c5 100644 --- a/drivers/i2c/busses/i2c-fsi.c +++ b/drivers/i2c/busses/i2c-fsi.c @@ -12,10 +12,12 @@ #include #include +#include #include #include #include #include +#include #include #include #include @@ -123,6 +125,20 @@ #define I2C_ESTAT_SELF_BUSY BIT(6) #define I2C_ESTAT_VERSION GENMASK(4, 0) +/* port busy register */ +#define I2C_PORT_BUSY_RESET BIT(31) + +/* wait for command complete or data request */ +#define I2C_CMD_SLEEP_MAX_US 500 +#define I2C_CMD_SLEEP_MIN_US 50 + +/* wait after reset; choose time from legacy driver */ +#define I2C_RESET_SLEEP_MAX_US 2000 +#define I2C_RESET_SLEEP_MIN_US 1000 + +/* choose timeout length from legacy driver; it's well tested */ +#define I2C_ABORT_TIMEOUT msecs_to_jiffies(100) + struct fsi_i2c_master { struct fsi_device *fsi; u8 fifo_size; @@ -209,6 +225,169 @@ static int fsi_i2c_set_port(struct fsi_i2c_port *port) return fsi_i2c_write_reg(fsi, I2C_FSI_RESET_ERR, &dummy); } +static int fsi_i2c_reset_bus(struct fsi_i2c_master *i2c) +{ + int i, rc; + u32 mode, stat, ext, dummy = 0; + + rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode); + if (rc) + return rc; + + mode |= I2C_MODE_DIAG; + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); + if (rc) + return rc; + + for (i = 0; i < 9; i++) { + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy); + if (rc) + return rc; + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy); + if (rc) + return rc; + } + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy); + if (rc) + return rc; + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SDA, &dummy); + if (rc) + return rc; + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy); + if (rc) + return rc; + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SDA, &dummy); + if (rc) + return rc; + + mode &= ~I2C_MODE_DIAG; + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); + if (rc) + return rc; + + rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_STAT, &stat); + if (rc) + return rc; + + /* check for hardware fault */ + if (!(stat & I2C_STAT_SCL_IN) || !(stat & I2C_STAT_SDA_IN)) { + rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_ESTAT, &ext); + if (rc) + return rc; + + dev_err(&i2c->fsi->dev, "bus stuck status[%08X] ext[%08X]\n", + stat, ext); + } + + return 0; +} + +static int fsi_i2c_reset(struct fsi_i2c_master *i2c, u16 port) +{ + int rc; + u32 mode, stat, dummy = 0; + + /* reset engine */ + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_I2C, &dummy); + if (rc) + return rc; + + /* re-init engine */ + rc = fsi_i2c_dev_init(i2c); + if (rc) + return rc; + + rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode); + if (rc) + return rc; + + /* set port; default after reset is 0 */ + if (port) { + mode &= ~I2C_MODE_PORT; + mode |= FIELD_PREP(I2C_MODE_PORT, port); + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); + if (rc) + return rc; + } + + /* reset busy register; hw workaround */ + dummy = I2C_PORT_BUSY_RESET; + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_PORT_BUSY, &dummy); + if (rc) + return rc; + + /* force bus reset */ + rc = fsi_i2c_reset_bus(i2c); + if (rc) + return rc; + + /* reset errors */ + dummy = 0; + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_ERR, &dummy); + if (rc) + return rc; + + /* wait for command complete */ + usleep_range(I2C_RESET_SLEEP_MIN_US, I2C_RESET_SLEEP_MAX_US); + + rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_STAT, &stat); + if (rc) + return rc; + + if (stat & I2C_STAT_CMD_COMP) + return rc; + + /* failed to get command complete; reset engine again */ + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_I2C, &dummy); + if (rc) + return rc; + + /* re-init engine again */ + return fsi_i2c_dev_init(i2c); +} + +static int fsi_i2c_abort(struct fsi_i2c_port *port, u32 status) +{ + int rc; + unsigned long start; + u32 cmd = I2C_CMD_WITH_STOP; + struct fsi_device *fsi = port->master->fsi; + + rc = fsi_i2c_reset(port->master, port->port); + if (rc) + return rc; + + /* skip final stop command for these errors */ + if (status & (I2C_STAT_PARITY | I2C_STAT_LOST_ARB | I2C_STAT_STOP_ERR)) + return 0; + + /* write stop command */ + rc = fsi_i2c_write_reg(fsi, I2C_FSI_CMD, &cmd); + if (rc) + return rc; + + /* wait until we see command complete in the master */ + start = jiffies; + + do { + rc = fsi_i2c_read_reg(fsi, I2C_FSI_STAT, &status); + if (rc) + return rc; + + if (status & I2C_STAT_CMD_COMP) + return 0; + + usleep_range(I2C_CMD_SLEEP_MIN_US, I2C_CMD_SLEEP_MAX_US); + } while (time_after(start + I2C_ABORT_TIMEOUT, jiffies)); + + return -ETIMEDOUT; +} + static int fsi_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { -- 1.8.3.1