| Message ID | 1484601219-30196-4-git-send-email-eajames.ibm@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
On 01/16/2017 01:13 PM, eajames.ibm@gmail.com wrote: > From: "Edward A. James" <eajames@us.ibm.com> > > Add functions to send SCOM operations over I2C bus. The BMC can > communicate with the Power8 host processor over I2C, but needs to use SCOM > operations in order to access the OCC register space. > > Signed-off-by: Edward A. James <eajames@us.ibm.com> > Signed-off-by: Andrew Jeffery <andrew@aj.id.au> > --- > drivers/hwmon/occ/occ_scom_i2c.c | 72 ++++++++++++++++++++++++++++++++++++++++ > drivers/hwmon/occ/occ_scom_i2c.h | 26 +++++++++++++++ > 2 files changed, 98 insertions(+) > create mode 100644 drivers/hwmon/occ/occ_scom_i2c.c > create mode 100644 drivers/hwmon/occ/occ_scom_i2c.h > > diff --git a/drivers/hwmon/occ/occ_scom_i2c.c b/drivers/hwmon/occ/occ_scom_i2c.c > new file mode 100644 > index 0000000..8b4ca13 > --- /dev/null > +++ b/drivers/hwmon/occ/occ_scom_i2c.c > @@ -0,0 +1,72 @@ > +/* > + * occ_scom_i2c.c - hwmon OCC driver > + * > + * This file contains the functions for performing SCOM operations over I2C bus > + * to access the OCC. > + * > + * Copyright 2016 IBM Corp. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include <linux/i2c.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include "occ_scom_i2c.h" > +#include "scom.h" > + > +int occ_i2c_getscom(void *bus, u32 address, u64 *data) > +{ > + ssize_t rc; > + u64 buf; > + struct i2c_client *client = bus; > + > + rc = i2c_master_send(client, (const char *)&address, sizeof(u32)); > + if (rc < 0) > + return rc; > + else if (rc != sizeof(u32)) > + return -EIO; > + > + rc = i2c_master_recv(client, (char *)&buf, sizeof(u64)); > + if (rc < 0) > + return rc; > + else if (rc != sizeof(u64)) > + return -EIO; > + > + *data = be64_to_cpu(buf); > + > + return 0; > +} > +EXPORT_SYMBOL(occ_i2c_getscom); > + > +int occ_i2c_putscom(void *bus, u32 address, u32 data0, u32 data1) > +{ > + u32 buf[3]; > + ssize_t rc; > + struct i2c_client *client = bus; > + > + buf[0] = address; > + buf[1] = data1; > + buf[2] = data0; > + Receive data is converted from be64 to host byte order, transmit data is sent as-is. Yet, if I recall correctly, some of the calling code passes in constants. Are you sure this works on both little and big endian systems ? > + rc = i2c_master_send(client, (const char *)buf, sizeof(u32) * 3); > + if (rc < 0) > + return rc; > + else if (rc != sizeof(u32) * 3) > + return -EIO; > + > + return 0; > +} > +EXPORT_SYMBOL(occ_i2c_putscom); > + > +MODULE_AUTHOR("Eddie James <eajames@us.ibm.com>"); > +MODULE_DESCRIPTION("I2C OCC SCOM transport"); > +MODULE_LICENSE("GPL"); > diff --git a/drivers/hwmon/occ/occ_scom_i2c.h b/drivers/hwmon/occ/occ_scom_i2c.h > new file mode 100644 > index 0000000..945739c > --- /dev/null > +++ b/drivers/hwmon/occ/occ_scom_i2c.h > @@ -0,0 +1,26 @@ > +/* > + * occ_scom_i2c.h - hwmon OCC driver > + * > + * This file contains function protoypes for peforming SCOM operations over I2C > + * bus to access the OCC. > + * > + * Copyright 2016 IBM Corp. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#ifndef __OCC_SCOM_I2C_H__ > +#define __OCC_SCOM_I2C_H__ > + > +int occ_i2c_getscom(void *bus, u32 address, u64 *data); > +int occ_i2c_putscom(void *bus, u32 address, u32 data0, u32 data1); > + > +#endif /* __OCC_SCOM_I2C_H__ */ > -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sat, 2017-01-21 at 10:11 -0800, Guenter Roeck wrote: > > +int occ_i2c_getscom(void *bus, u32 address, u64 *data) > > +{ > > + ssize_t rc; > > + u64 buf; > > + struct i2c_client *client = bus; > > + > > + rc = i2c_master_send(client, (const char *)&address, > > sizeof(u32)); > > + if (rc < 0) > > + return rc; > > + else if (rc != sizeof(u32)) > > + return -EIO; > > + > > + rc = i2c_master_recv(client, (char *)&buf, sizeof(u64)); > > + if (rc < 0) > > + return rc; > > + else if (rc != sizeof(u64)) > > + return -EIO; > > + > > + *data = be64_to_cpu(buf); > > + > > + return 0; > > +} > > +EXPORT_SYMBOL(occ_i2c_getscom); Additionally, this assumes that is is the only other user of that i2c path to P8. Something interleaving will break it. pdbg for example. Talk to Alistair, the right thing here would probably be to have a separate driver that provides the XSCOM interface via i2c to both in-kernel and userspace, with proper arbitration. An expedient might be to instead have the address and data cycles of the above be 2 i2c messages in one i2c request, thus being serialized somewhat atomically with other transactions to that i2c bus. You may need to make sure the underlying i2c controller driver supports dual messages, and if it doesn't fix it. This is rather classic 4-bytes subaddress style i2c, it shouldn't be too hard. Cheers, Ben. -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/hwmon/occ/occ_scom_i2c.c b/drivers/hwmon/occ/occ_scom_i2c.c new file mode 100644 index 0000000..8b4ca13 --- /dev/null +++ b/drivers/hwmon/occ/occ_scom_i2c.c @@ -0,0 +1,72 @@ +/* + * occ_scom_i2c.c - hwmon OCC driver + * + * This file contains the functions for performing SCOM operations over I2C bus + * to access the OCC. + * + * Copyright 2016 IBM Corp. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/i2c.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include "occ_scom_i2c.h" +#include "scom.h" + +int occ_i2c_getscom(void *bus, u32 address, u64 *data) +{ + ssize_t rc; + u64 buf; + struct i2c_client *client = bus; + + rc = i2c_master_send(client, (const char *)&address, sizeof(u32)); + if (rc < 0) + return rc; + else if (rc != sizeof(u32)) + return -EIO; + + rc = i2c_master_recv(client, (char *)&buf, sizeof(u64)); + if (rc < 0) + return rc; + else if (rc != sizeof(u64)) + return -EIO; + + *data = be64_to_cpu(buf); + + return 0; +} +EXPORT_SYMBOL(occ_i2c_getscom); + +int occ_i2c_putscom(void *bus, u32 address, u32 data0, u32 data1) +{ + u32 buf[3]; + ssize_t rc; + struct i2c_client *client = bus; + + buf[0] = address; + buf[1] = data1; + buf[2] = data0; + + rc = i2c_master_send(client, (const char *)buf, sizeof(u32) * 3); + if (rc < 0) + return rc; + else if (rc != sizeof(u32) * 3) + return -EIO; + + return 0; +} +EXPORT_SYMBOL(occ_i2c_putscom); + +MODULE_AUTHOR("Eddie James <eajames@us.ibm.com>"); +MODULE_DESCRIPTION("I2C OCC SCOM transport"); +MODULE_LICENSE("GPL"); diff --git a/drivers/hwmon/occ/occ_scom_i2c.h b/drivers/hwmon/occ/occ_scom_i2c.h new file mode 100644 index 0000000..945739c --- /dev/null +++ b/drivers/hwmon/occ/occ_scom_i2c.h @@ -0,0 +1,26 @@ +/* + * occ_scom_i2c.h - hwmon OCC driver + * + * This file contains function protoypes for peforming SCOM operations over I2C + * bus to access the OCC. + * + * Copyright 2016 IBM Corp. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#ifndef __OCC_SCOM_I2C_H__ +#define __OCC_SCOM_I2C_H__ + +int occ_i2c_getscom(void *bus, u32 address, u64 *data); +int occ_i2c_putscom(void *bus, u32 address, u32 data0, u32 data1); + +#endif /* __OCC_SCOM_I2C_H__ */