linux-kernel - Re: [char-misc-next 2/2] mei: send OS type to the FW

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Date:   Thu, 10 Nov 2016 08:24:33 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Tomas Winkler <tomas.winkler@...el.com>
Cc:     Alexander Usyskin <alexander.usyskin@...el.com>,
        linux-kernel@...r.kernel.org,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Subject: Re: [char-misc-next 2/2] mei: send OS type to the FW

On Tue, Nov 08, 2016 at 06:26:09PM +0200, Tomas Winkler wrote:
> From: Alexander Usyskin <alexander.usyskin@...el.com>
> 
> Tell the FW that we are running a sane OS and TPM2_ChangeEPS()
> is supported. This workaround was added to support other broken OS
> and we need to follow here. The command is sent just once at the boot time.
> 
> Cc: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
> Signed-off-by: Alexander Usyskin <alexander.usyskin@...el.com>
> ---
>  drivers/misc/mei/bus-fixup.c | 98 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 98 insertions(+)
> 
> diff --git a/drivers/misc/mei/bus-fixup.c b/drivers/misc/mei/bus-fixup.c
> index 9e10d86e3887..344a0c99ee44 100644
> --- a/drivers/misc/mei/bus-fixup.c
> +++ b/drivers/misc/mei/bus-fixup.c
> @@ -38,6 +38,9 @@ static const uuid_le mei_nfc_info_guid = MEI_UUID_NFC_INFO;
>  #define MEI_UUID_WD UUID_LE(0x05B79A6F, 0x4628, 0x4D7F, \
>  			    0x89, 0x9D, 0xA9, 0x15, 0x14, 0xCB, 0x32, 0xAB)
>  
> +#define MEI_UUID_MKHIF_FIX UUID_LE(0x55213584, 0x9a29, 0x4916, \
> +			0xba, 0xdf, 0xf, 0xb7, 0xed, 0x68, 0x2a, 0xeb)
> +
>  #define MEI_UUID_ANY NULL_UUID_LE
>  
>  /**
> @@ -69,6 +72,100 @@ static void blacklist(struct mei_cl_device *cldev)
>  	cldev->do_match = 0;
>  }
>  
> +#define OSTYPE_LINUX    2
> +struct mei_os_ver {
> +	u16 build;
> +	u16 reserved1;
> +	u8  os_type;
> +	u8  major;
> +	u8  minor;
> +	u8  reserved2;
> +} __packed;
> +
> +#define MKHI_FEATURE_PTT 0x10
> +
> +struct mkhi_rule_id {
> +	u16 rule_type;

Endian?

> +	u8 feature_id;
> +	u8 reserved;
> +} __packed;
> +
> +struct mkhi_fwcaps {
> +	struct mkhi_rule_id id;
> +	u8 len;
> +	u8 data[0];
> +} __packed;
> +
> +#define MKHI_FWCAPS_GROUP_ID 0x3
> +#define MKHI_FWCAPS_SET_OS_VER_APP_RULE_CMD 6
> +struct mkhi_msg_hdr {
> +	u32  group_id    :8;
> +	u32  command     :7;
> +	u32  is_response :1;
> +	u32  reserved    :8;
> +	u32  result      :8;

Oh that's scary, does this really work?  It's usually better to use
bitmasks to get the values out properly.

> +};
> +
> +struct mkhi_msg {
> +	struct mkhi_msg_hdr hdr;
> +	u8 data[0];
> +} __packed;
> +
> +static int mei_osver(struct mei_cl_device *cldev)
> +{
> +	int ret;
> +	const size_t size = sizeof(struct mkhi_msg_hdr) +
> +			    sizeof(struct mkhi_fwcaps) +
> +			    sizeof(struct mei_os_ver);
> +	size_t length = 8;
> +	char buf[size];
> +	struct mkhi_msg *req;
> +	struct mkhi_fwcaps *fwcaps;
> +	struct mei_os_ver *os_ver;
> +	unsigned int mode = MEI_CL_IO_TX_BLOCKING | MEI_CL_IO_TX_INTERNAL;
> +
> +	memset(buf, 0, size);
> +
> +	req = (struct mkhi_msg *)buf;
> +	req->hdr.group_id = MKHI_FWCAPS_GROUP_ID;
> +	req->hdr.command = MKHI_FWCAPS_SET_OS_VER_APP_RULE_CMD;
> +
> +	fwcaps = (struct mkhi_fwcaps *)req->data;
> +
> +	fwcaps->id.rule_type = 0x0;
> +	fwcaps->id.feature_id = MKHI_FEATURE_PTT;
> +	fwcaps->len = sizeof(*os_ver);
> +	os_ver = (struct mei_os_ver *)fwcaps->data;
> +	os_ver->os_type = OSTYPE_LINUX;
> +
> +	ret = __mei_cl_send(cldev->cl, buf, size, mode);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = __mei_cl_recv(cldev->cl, buf, length);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static void mei_mkhi_fix(struct mei_cl_device *cldev)
> +{
> +	int ret;
> +
> +	dev_dbg(&cldev->dev, "running hook %s\n", __func__);

ftrace can provide you this, right?

> +
> +	ret = mei_cldev_enable(cldev);
> +	if (ret)
> +		return;
> +
> +	ret = mei_osver(cldev);
> +	if (ret)
> +		dev_info(&cldev->dev, "OS version command failed\n");

dev_err()?

And what about the error value?

thanks,

greg k-h