linux-kernel - Re: [PATCH 1/3] tpm_crb: map locality registers

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Message-ID: <20161011170143.GC6881@obsidianresearch.com>
Date:   Tue, 11 Oct 2016 11:01:43 -0600
From:   Jason Gunthorpe <jgunthorpe@...idianresearch.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Cc:     Peter Huewe <peterhuewe@....de>,
        Marcel Selhorst <tpmdd@...horst.net>,
        "moderated list:TPM DEVICE DRIVER" 
        <tpmdd-devel@...ts.sourceforge.net>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] tpm_crb: map locality registers

On Tue, Oct 11, 2016 at 12:23:04PM +0300, Jarkko Sakkinen wrote:
> In order to provide access to locality registers, this commits adds
> mapping of the head of the CRB registers, which are located right
> before the control area.

I think you should squash this into the prior patch, no sense in
changing all these lines twice

But looks better to me.

> -	priv->cca = crb_map_res(dev, priv, &io_res, buf->control_address,
> -				sizeof(struct crb_control_area));
> -	if (IS_ERR(priv->cca))
> -		return PTR_ERR(priv->cca);
> +	if (priv->flags & CRB_FL_CRB_START) {
> +		priv->regs_h = crb_map_res(dev, priv, &io_res, io_res.start,
> +					   sizeof(struct crb_regs_head));
> +		if (IS_ERR(priv->regs_h))
> +			return PTR_ERR(priv->regs_h);
> +	}
> +
> +	priv->regs_t = crb_map_res(dev, priv, &io_res, buf->control_address,
> +				   sizeof(struct crb_regs_tail));
> +	if (IS_ERR(priv->regs_t))
> +		return PTR_ERR(priv->regs_t);

So.. The ACPI IO region starts at the head area and continues to
include the control area, as one nice sane region - except for some
older stuff that puts the control area outside the ACPI IO region?

That makes a lot more sense..

Maybe chuck in a

   if (priv->flags & CRB_FL_CRB_START) {
      if (buf->control_address != io_res.start + sizeof(struct
          crb_regs_head))
          dev_warn(dev, FIRMWARE_BUG "Bad ACPI memory layout")

Jason