From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 In-Reply-To: <568A7A4A.4000308@samsung.com> References: <1450280249-24681-1-git-send-email-m.szyprowski@samsung.com> <1450280249-24681-4-git-send-email-m.szyprowski@samsung.com> <568A7A4A.4000308@samsung.com> Date: Mon, 4 Jan 2016 15:36:29 -0600 Message-ID: Subject: Re: [PATCH v3 3/7] of: reserved_mem: add support for named reserved mem nodes From: Rob Herring Content-Type: text/plain; charset=UTF-8 To: Marek Szyprowski Cc: "linux-media@vger.kernel.org" , "linux-samsung-soc@vger.kernel.org" , "devicetree@vger.kernel.org" , Sylwester Nawrocki , Kamil Debski , Laurent Pinchart , Andrzej Hajda , Kukjin Kim , Krzysztof Kozlowski , Bartlomiej Zolnierkiewicz , Frank Rowand , Grant Likely List-ID: On Mon, Jan 4, 2016 at 7:57 AM, Marek Szyprowski wrote: > Hi Rob, > > > On 2015-12-31 00:25, Rob Herring wrote: >> >> On Wed, Dec 16, 2015 at 9:37 AM, Marek Szyprowski >> wrote: >>> >>> This patch allows device drivers to initialize more than one reserved >>> memory region assigned to given device. When driver needs to use more >>> than one reserved memory region, it should allocate child devices and >>> initialize regions by index or name for each of its child devices. >>> >>> Signed-off-by: Marek Szyprowski >>> --- >>> .../bindings/reserved-memory/reserved-memory.txt | 2 + >>> .../devicetree/bindings/resource-names.txt | 1 + >>> drivers/of/of_reserved_mem.c | 104 >>> +++++++++++++++++---- >>> include/linux/of_reserved_mem.h | 31 +++++- >>> 4 files changed, 115 insertions(+), 23 deletions(-) >>> >>> diff --git >>> a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt >>> b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt >>> index 3da0ebdba8d9..43a14957fd64 100644 >>> --- >>> a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt >>> +++ >>> b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt >>> @@ -74,6 +74,8 @@ Regions in the /reserved-memory node may be referenced >>> by other device >>> nodes by adding a memory-region property to the device node. >>> >>> memory-region (optional) - phandle, specifier pairs to children of >>> /reserved-memory >>> +memory-region-names (optional) - supplemental names property, provide >>> array of >>> + names to identify memory regions >>> >>> Example >>> ------- >>> diff --git a/Documentation/devicetree/bindings/resource-names.txt >>> b/Documentation/devicetree/bindings/resource-names.txt >>> index e280fef6f265..51823e99b983 100644 >>> --- a/Documentation/devicetree/bindings/resource-names.txt >>> +++ b/Documentation/devicetree/bindings/resource-names.txt >>> @@ -12,6 +12,7 @@ Resource Property Supplemental Names Property >>> reg reg-names >>> clocks clock-names >>> interrupts interrupt-names >>> +memory-region memory-region-names >> >> The other cases of *-names should correspond to actual h/w names for a >> h/w block. memory-regions are not really h/w. So I'd prefer to not add >> memory-region-names. If you want a name for the region, put it in the >> region node. The name for each client node is not going to be >> different. > > > There is a difference between a name in the region node and a name assigned > in client node. Reserved memory region bindings already allows assigning > given region to more than one device. In such case the name put in the > region itself is not really useful. > > In my case (Exynos MFC device) the names are related to HW names. The memory > regions are named in the hw documentation (referred as 'left memory bank' > and 'right memory bank'). Using those names in the binding is also simply > convenient (no need to remember which regions is at which index number). > > Those names might be also convenient for describing Android's ION related > regions, although I didn't look deep into details of such use case. > > Best regards > -- > Marek Szyprowski, PhD > Samsung R&D Institute Poland >