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SubjectRE: [PATCH v5] drivers: ipmi: Support raw i2c packet in IPMB
Date

-----Original Message-----
From: Vijay Khemka <vijaykhemka@fb.com>
Sent: Thursday, November 14, 2019 1:54 PM
To: Jonathan Corbet <corbet@lwn.net>; Corey Minyard <minyard@acm.org>; Arnd Bergmann <arnd@arndb.de>; Greg Kroah-Hartman <gregkh@linuxfoundation.org>; linux-doc@vger.kernel.org; linux-kernel@vger.kernel.org; openipmi-developer@lists.sourceforge.net
Cc: vijaykhemka@fb.com; cminyard@mvista.com; Asmaa Mnebhi <Asmaa@mellanox.com>; joel@jms.id.au; linux-aspeed@lists.ozlabs.org; sdasari@fb.com
Subject: [PATCH v5] drivers: ipmi: Support raw i2c packet in IPMB

Many IPMB devices doesn't support smbus protocol and current driver support only smbus devices. Added support for raw i2c packets.

User can define i2c-protocol in device tree to use i2c raw transfer.

Asmaa >> It would be good if you can rephrase the above description as follows:
"The ipmb_dev_int driver only supports the smbus protocol at the moment. Add support for the i2c protocol as well. There will be a variable passed by the device tree or ACPI table which determines whether the protocol is i2c or smbus."

Or at least fix the following:
"Many IPMB devices doesn't" -> "Many IPMB devices don't"
"current driver support" -> "current driver supports"

Besides my above comment:
Reviewed-by: Asmaa Mnebhi <asmaa@mellanox.com>

Signed-off-by: Vijay Khemka <vijaykhemka@fb.com>
---
Documentation/IPMB.txt | 4 ++++
drivers/char/ipmi/ipmb_dev_int.c | 29 +++++++++++++++++++++++++++++
2 files changed, 33 insertions(+)

diff --git a/Documentation/IPMB.txt b/Documentation/IPMB.txt index a6ed8b68bd0f..7a023beff976 100644
--- a/Documentation/IPMB.txt
+++ b/Documentation/IPMB.txt
@@ -71,9 +71,13 @@ b) Example for device tree:
ipmb@10 {
compatible = "ipmb-dev";
reg = <0x10>;
+ i2c-protocol;
};
};

+If xmit of data to be done using raw i2c block vs smbus then
+"i2c-protocol" needs to be defined as above.
+
2) Manually from Linux:
modprobe ipmb-dev-int

diff --git a/drivers/char/ipmi/ipmb_dev_int.c b/drivers/char/ipmi/ipmb_dev_int.c
index ae3bfba27526..68a254c0dd92 100644
--- a/drivers/char/ipmi/ipmb_dev_int.c
+++ b/drivers/char/ipmi/ipmb_dev_int.c
@@ -63,6 +63,7 @@ struct ipmb_dev {
spinlock_t lock;
wait_queue_head_t wait_queue;
struct mutex file_mutex;
+ bool is_i2c_protocol;
};

static inline struct ipmb_dev *to_ipmb_dev(struct file *file) @@ -112,6 +113,25 @@ static ssize_t ipmb_read(struct file *file, char __user *buf, size_t count,
return ret < 0 ? ret : count;
}

+static int ipmb_i2c_write(struct i2c_client *client, u8 *msg, u8 addr)
+{
+ struct i2c_msg i2c_msg;
+
+ /*
+ * subtract 1 byte (rq_sa) from the length of the msg passed to
+ * raw i2c_transfer
+ */
+ i2c_msg.len = msg[IPMB_MSG_LEN_IDX] - 1;
+
+ /* Assign message to buffer except first 2 bytes (length and address) */
+ i2c_msg.buf = msg + 2;
+
+ i2c_msg.addr = addr;
+ i2c_msg.flags = client->flags & I2C_CLIENT_PEC;
+
+ return i2c_transfer(client->adapter, &i2c_msg, 1); }
+
static ssize_t ipmb_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
@@ -133,6 +153,12 @@ static ssize_t ipmb_write(struct file *file, const char __user *buf,
rq_sa = GET_7BIT_ADDR(msg[RQ_SA_8BIT_IDX]);
netf_rq_lun = msg[NETFN_LUN_IDX];

+ /* Check i2c block transfer vs smbus */
+ if (ipmb_dev->is_i2c_protocol) {
+ ret = ipmb_i2c_write(ipmb_dev->client, msg, rq_sa);
+ return (ret == 1) ? count : ret;
+ }
+
/*
* subtract rq_sa and netf_rq_lun from the length of the msg passed to
* i2c_smbus_xfer
@@ -302,6 +328,9 @@ static int ipmb_probe(struct i2c_client *client,
if (ret)
return ret;

+ ipmb_dev->is_i2c_protocol
+ = device_property_read_bool(&client->dev, "i2c-protocol");
+
ipmb_dev->client = client;
i2c_set_clientdata(client, ipmb_dev);
ret = i2c_slave_register(client, ipmb_slave_cb);
--
2.17.1
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