From patchwork Mon Apr 4 10:03:15 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Samuel Ortiz X-Patchwork-Id: 684841 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p34A3rj6002354 for ; Mon, 4 Apr 2011 10:03:53 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754318Ab1DDKDW (ORCPT ); Mon, 4 Apr 2011 06:03:22 -0400 Received: from mga11.intel.com ([192.55.52.93]:25577 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753642Ab1DDKDV (ORCPT ); Mon, 4 Apr 2011 06:03:21 -0400 Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga102.fm.intel.com with ESMTP; 04 Apr 2011 03:03:20 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.63,296,1299484800"; d="scan'208";a="674921237" Received: from unknown (HELO sortiz-mobl) ([10.255.16.156]) by fmsmga002.fm.intel.com with ESMTP; 04 Apr 2011 03:03:16 -0700 Date: Mon, 4 Apr 2011 12:03:15 +0200 From: Samuel Ortiz To: Grant Likely Cc: Andres Salomon , linux-kernel@vger.kernel.org, Mark Brown , khali@linux-fr.org, ben-linux@fluff.org, Peter Korsgaard , Mauro Carvalho Chehab , David Brownell , linux-i2c@vger.kernel.org, linux-media@vger.kernel.org, netdev@vger.kernel.org, spi-devel-general@lists.sourceforge.net, Mocean Laboratories , Greg Kroah-Hartman Subject: Re: [PATCH 07/19] timberdale: mfd_cell is now implicitly available to drivers Message-ID: <20110404100314.GC2751@sortiz-mobl> References: <20110202195417.228e2656@queued.net> <20110202200812.3d8d6cba@queued.net> <20110331230522.GI437@ponder.secretlab.ca> <20110401112030.GA3447@sortiz-mobl> <20110401104756.2f5c6f7a@debxo> <20110401235239.GE29397@sortiz-mobl> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Mon, 04 Apr 2011 10:03:53 +0000 (UTC) On Fri, Apr 01, 2011 at 05:58:44PM -0600, Grant Likely wrote: > On Fri, Apr 1, 2011 at 5:52 PM, Samuel Ortiz wrote: > > On Fri, Apr 01, 2011 at 11:56:35AM -0600, Grant Likely wrote: > >> On Fri, Apr 1, 2011 at 11:47 AM, Andres Salomon wrote: > >> > On Fri, 1 Apr 2011 13:20:31 +0200 > >> > Samuel Ortiz wrote: > >> > > >> >> Hi Grant, > >> >> > >> >> On Thu, Mar 31, 2011 at 05:05:22PM -0600, Grant Likely wrote: > >> > [...] > >> >> > Gah.  Not all devices instantiated via mfd will be an mfd device, > >> >> > which means that the driver may very well expect an *entirely > >> >> > different* platform_device pointer; which further means a very high > >> >> > potential of incorrectly dereferenced structures (as evidenced by a > >> >> > patch series that is not bisectable).  For instance, the xilinx ip > >> >> > cores are used by more than just mfd. > >> >> I agree. Since the vast majority of the MFD subdevices are MFD > >> >> specific IPs, I overlooked that part. The impacted drivers are the > >> >> timberdale and the DaVinci voice codec ones. > >> > >> Another option is you could do this for MFD devices: > >> > >> struct mfd_device { > >>         struct platform_devce pdev; > >>         struct mfd_cell *cell; > >> }; > >> > >> However, that requires that drivers using the mfd_cell will *never* > >> get instantiated outside of the mfd infrastructure, and there is no > >> way to protect against this so it is probably a bad idea. > >> > >> Or, mfd_cell could be added to platform_device directly which would > >> *by far* be the safest option at the cost of every platform_device > >> having a mostly unused mfd_cell pointer.  Not a significant cost in my > >> opinion. > > I thought about this one, but I had the impression people would want to kill > > me for adding an MFD specific pointer to platform_device. I guess it's worth > > giving it a try since it would be a simple and safe solution. > > I'll look at it later this weekend. > > > > Thanks for the input. > > [cc'ing gregkh because we're talking about modifying struct platform_device] > > I'll back you up on this one. It is a far better solution than the > alternatives. At least with mfd, it covers a large set of devices. I > think there is a strong argument for doing this. Or alternatively, > the particular interesting fields from mfd_cell could be added to > platform_device. What information do child devices need access to? In some cases, they need the whole cell to clone it. So I'm up for adding an mfd_cell pointer to the platform_device structure. Below is a tentative patch. This is a first step and would fix all regressions. I tried to keep the MFD dependencies as small as possible, which is why I placed the pdev->mfd_cell building code in mfd-core.c The second step would be to get rid of mfd_get_data() and have all subdrivers going back to the regular platform_data way. They would no longer be dependant on the MFD code except for those who really need it. In that case they could just call mfd_get_cell() and get full access to their MFD cell. --- drivers/mfd/mfd-core.c | 27 ++++++++++++++++++++++----- include/linux/mfd/core.h | 7 +++++-- include/linux/platform_device.h | 5 +++++ 3 files changed, 32 insertions(+), 7 deletions(-) diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c index d01574d..c0fc1c0 100644 --- a/drivers/mfd/mfd-core.c +++ b/drivers/mfd/mfd-core.c @@ -18,6 +18,21 @@ #include #include +static int mfd_platform_add_cell(struct platform_device *pdev, const struct mfd_cell *cell) +{ + struct mfd_cell *c; + + if (cell == NULL) + return 0; + + c = kmemdup(cell, sizeof(struct mfd_cell), GFP_KERNEL); + if (c == NULL) + return -ENOMEM; + + pdev->mfd_cell = c; + return 0; +} + int mfd_cell_enable(struct platform_device *pdev) { const struct mfd_cell *cell = mfd_get_cell(pdev); @@ -75,7 +90,7 @@ static int mfd_add_device(struct device *parent, int id, pdev->dev.parent = parent; - ret = platform_device_add_data(pdev, cell, sizeof(*cell)); + ret = mfd_platform_add_cell(pdev, cell); if (ret) goto fail_res; @@ -104,17 +119,17 @@ static int mfd_add_device(struct device *parent, int id, if (!cell->ignore_resource_conflicts) { ret = acpi_check_resource_conflict(res); if (ret) - goto fail_res; + goto fail_cell; } } ret = platform_device_add_resources(pdev, res, cell->num_resources); if (ret) - goto fail_res; + goto fail_cell; ret = platform_device_add(pdev); if (ret) - goto fail_res; + goto fail_cell; if (cell->pm_runtime_no_callbacks) pm_runtime_no_callbacks(&pdev->dev); @@ -123,7 +138,8 @@ static int mfd_add_device(struct device *parent, int id, return 0; -/* platform_device_del(pdev); */ +fail_cell: + kfree(pdev->mfd_cell); fail_res: kfree(res); fail_device: @@ -171,6 +187,7 @@ static int mfd_remove_devices_fn(struct device *dev, void *c) if (!*usage_count || (cell->usage_count < *usage_count)) *usage_count = cell->usage_count; + kfree(pdev->mfd_cell); platform_device_unregister(pdev); return 0; } diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h index ad1b19a..0e4d3a6 100644 --- a/include/linux/mfd/core.h +++ b/include/linux/mfd/core.h @@ -86,7 +86,7 @@ extern int mfd_clone_cell(const char *cell, const char **clones, */ static inline const struct mfd_cell *mfd_get_cell(struct platform_device *pdev) { - return pdev->dev.platform_data; + return pdev->mfd_cell; } /* @@ -95,7 +95,10 @@ static inline const struct mfd_cell *mfd_get_cell(struct platform_device *pdev) */ static inline void *mfd_get_data(struct platform_device *pdev) { - return mfd_get_cell(pdev)->mfd_data; + if (pdev->mfd_cell != NULL) + return mfd_get_cell(pdev)->mfd_data; + else + return pdev->dev.platform_data; } extern int mfd_add_devices(struct device *parent, int id, diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h index d96db98..734d254 100644 --- a/include/linux/platform_device.h +++ b/include/linux/platform_device.h @@ -14,6 +14,8 @@ #include #include +struct mfd_cell; + struct platform_device { const char * name; int id; @@ -23,6 +25,9 @@ struct platform_device { const struct platform_device_id *id_entry; + /* MFD cell pointer */ + struct mfd_cell *mfd_cell; + /* arch specific additions */ struct pdev_archdata archdata; };