RE: [PATCH] drivers: ipmi: Support for both IPMB Req and Resp

From: Asmaa Mnebhi
Date: Wed Nov 06 2019 - 10:01:15 EST




-----Original Message-----
From: Vijay Khemka <vijaykhemka@xxxxxx>
Sent: Wednesday, November 6, 2019 1:58 AM
To: minyard@xxxxxxx
Cc: Arnd Bergmann <arnd@xxxxxxxx>; Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>; openipmi-developer@xxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; cminyard@xxxxxxxxxx; Asmaa Mnebhi <Asmaa@xxxxxxxxxxxx>; joel@xxxxxxxxx; linux-aspeed@xxxxxxxxxxxxxxxx; Sai Dasari <sdasari@xxxxxx>
Subject: Re: [PATCH] drivers: ipmi: Support for both IPMB Req and Resp



ïOn 11/5/19, 4:54 PM, "Corey Minyard" <tcminyard@xxxxxxxxx on behalf of minyard@xxxxxxx> wrote:

On Tue, Nov 05, 2019 at 11:47:31AM -0800, Vijay Khemka wrote:
> Removed check for request or response in IPMB packets coming from
> device as well as from host. Now it supports both way communication
> to device via IPMB. Both request and response will be passed to
> application.
>
> Signed-off-by: Vijay Khemka <vijaykhemka@xxxxxx>
> ---
> drivers/char/ipmi/ipmb_dev_int.c | 29 +----------------------------
> 1 file changed, 1 insertion(+), 28 deletions(-)
>
> diff --git a/drivers/char/ipmi/ipmb_dev_int.c b/drivers/char/ipmi/ipmb_dev_int.c
> index 285e0b8f9a97..7201fdb533d8 100644
> --- a/drivers/char/ipmi/ipmb_dev_int.c
> +++ b/drivers/char/ipmi/ipmb_dev_int.c
> @@ -133,9 +133,6 @@ 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];
>
> - if (!(netf_rq_lun & NETFN_RSP_BIT_MASK))
> - return -EINVAL;
> -
> /*
> * subtract rq_sa and netf_rq_lun from the length of the msg passed to
> * i2c_smbus_xfer
> @@ -203,28 +200,6 @@ static u8 ipmb_verify_checksum1(struct ipmb_dev *ipmb_dev, u8 rs_sa)
> ipmb_dev->request.checksum1);
> }
>
> -static bool is_ipmb_request(struct ipmb_dev *ipmb_dev, u8 rs_sa)
> -{
> - if (ipmb_dev->msg_idx >= IPMB_REQUEST_LEN_MIN) {
> - if (ipmb_verify_checksum1(ipmb_dev, rs_sa))
> - return false;

You still need to check the message length and checksum, you just need
to ignore the req/resp bit.
Yes you are right, I was looking for checksum code after removing it __. I will modify it.

Besides Corey's comment, looks good to me. The logic should be something like this:
static bool is_ipmb_msg(struct ipmb_dev *ipmb_dev, u8 rs_sa)
{
if (ipmb_dev->msg_idx >= IPMB_REQUEST_LEN_MIN) {
if (ipmb_verify_checksum1(ipmb_dev, rs_sa))
return false;
} else {
return false;
}
return true;
}

-corey

> -
> - /*
> - * Check whether this is an IPMB request or
> - * response.
> - * The 6 MSB of netfn_rs_lun are dedicated to the netfn
> - * while the remaining bits are dedicated to the lun.
> - * If the LSB of the netfn is cleared, it is associated
> - * with an IPMB request.
> - * If the LSB of the netfn is set, it is associated with
> - * an IPMB response.
> - */
> - if (!(ipmb_dev->request.netfn_rs_lun & NETFN_RSP_BIT_MASK))
> - return true;
> - }
> - return false;
> -}
> -
> /*
> * The IPMB protocol only supports I2C Writes so there is no need
> * to support I2C_SLAVE_READ* events.
> @@ -273,9 +248,7 @@ static int ipmb_slave_cb(struct i2c_client *client,
>
> case I2C_SLAVE_STOP:
> ipmb_dev->request.len = ipmb_dev->msg_idx;
> -
> - if (is_ipmb_request(ipmb_dev, GET_8BIT_ADDR(client->addr)))
> - ipmb_handle_request(ipmb_dev);
> + ipmb_handle_request(ipmb_dev);

Keep this line.
> break;
>
> default:
> --
> 2.17.1
>