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

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Message-ID: <DB6PR0501MB2712BEF34969BF377E71B691DA790@DB6PR0501MB2712.eurprd05.prod.outlook.com>
Date:   Wed, 6 Nov 2019 15:01:07 +0000
From:   Asmaa Mnebhi <Asmaa@...lanox.com>
To:     Vijay Khemka <vijaykhemka@...com>,
        "minyard@....org" <minyard@....org>
CC:     Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "openipmi-developer@...ts.sourceforge.net" 
        <openipmi-developer@...ts.sourceforge.net>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "cminyard@...sta.com" <cminyard@...sta.com>,
        "joel@....id.au" <joel@....id.au>,
        "linux-aspeed@...ts.ozlabs.org" <linux-aspeed@...ts.ozlabs.org>,
        Sai Dasari <sdasari@...com>
Subject: RE: [PATCH] drivers: ipmi: Support for both IPMB Req and Resp



-----Original Message-----
From: Vijay Khemka <vijaykhemka@...com> 
Sent: Wednesday, November 6, 2019 1:58 AM
To: minyard@....org
Cc: Arnd Bergmann <arnd@...db.de>; Greg Kroah-Hartman <gregkh@...uxfoundation.org>; openipmi-developer@...ts.sourceforge.net; linux-kernel@...r.kernel.org; cminyard@...sta.com; Asmaa Mnebhi <Asmaa@...lanox.com>; joel@....id.au; linux-aspeed@...ts.ozlabs.org; Sai Dasari <sdasari@...com>
Subject: Re: [PATCH] drivers: ipmi: Support for both IPMB Req and Resp



On 11/5/19, 4:54 PM, "Corey Minyard" <tcminyard@...il.com on behalf of minyard@....org> 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@...com>
    > ---
    >  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
    >