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Message-ID: <Zr-SRo10QtSh4G9R@pluto>
Date: Fri, 16 Aug 2024 18:54:14 +0100
From: Cristian Marussi <cristian.marussi@....com>
To: Florian Fainelli <florian.fainelli@...adcom.com>
Cc: Cristian Marussi <cristian.marussi@....com>,
linux-kernel@...r.kernel.org, Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>,
Sudeep Holla <sudeep.holla@....com>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" <devicetree@...r.kernel.org>,
"open list:SYSTEM CONTROL & POWER/MANAGEMENT INTERFACE" <arm-scmi@...r.kernel.org>,
"moderated list:SYSTEM CONTROL & POWER/MANAGEMENT INTERFACE" <linux-arm-kernel@...ts.infradead.org>,
justin.chen@...adcom.com, opendmb@...il.com,
kapil.hali@...adcom.com, bcm-kernel-feedback-list@...adcom.com
Subject: Re: [PATCH v2 2/2] firmware: arm_scmi: Support 'reg-io-width'
property for shared memory
On Fri, Aug 16, 2024 at 10:39:42AM -0700, Florian Fainelli wrote:
> On 8/16/24 10:02, Cristian Marussi wrote:
> > On Tue, Aug 13, 2024 at 11:07:47AM -0700, Florian Fainelli wrote:
> > > Some shared memory areas might only support a certain access width,
> > > such as 32-bit, which memcpy_{from,to}_io() does not adhere to at least
> > > on ARM64 by making both 8-bit and 64-bit accesses to such memory.
> > >
> > > Update the shmem layer to support reading from and writing to such
> > > shared memory area using the specified I/O width in the Device Tree. The
> > > various transport layers making use of the shmem.c code are updated
> > > accordingly to pass the I/O accessors that they store.
> > >
> >
> > Hi Florian,
> >
Hi,
> > I gave it ago at this on a JUNO regarding the mailbox/shmem transport
> > without any issue. I'll have a go later on an OPTEE/shmem scenario too.
> >
> > This looks fundamentally good to me, since you moved all ops setup at
> > setup time and you keep the pointers per-channel instead of global...
>
> Thanks!
>
[snip]
> > > +
> >
> > There are a bunch of warn/errs from checkpatch --strict, beside the volatile
> > here and on the previous typedefs, also about args reuse and trailing semicolon
> > in these macros...
>
> I don't think we can silence the volatile ones, checkpatch --strict did not
> complain about the typedefs in my case, what did it look like in yours?
...I dont get warns on new typedefs..only on volatile and macro args
reuse
---8<---
WARNING: Use of volatile is usually wrong: see Documentation/process/volatile-considered-harmful.rst
#36: FILE: drivers/firmware/arm_scmi/common.h:322:
+typedef void (*shmem_copy_toio_t)(volatile void __iomem *to, const void *from,
WARNING: Use of volatile is usually wrong: see Documentation/process/volatile-considered-harmful.rst
#38: FILE: drivers/firmware/arm_scmi/common.h:324:
+typedef void (*shmem_copy_fromio_t)(void *to, const volatile void __iomem *from,
CHECK: Macro argument reuse 'amt' - possible side-effects?
#94: FILE: drivers/firmware/arm_scmi/shmem.c:37:
+#define SHMEM_IO_OPS(w, s, amt) \
+static inline void shmem_memcpy_fromio##s(void *to, \
+ const volatile void __iomem *from, \
+ size_t count) \
+{ \
+ while (count) { \
+ *(u##s *)to = __raw_read##w(from); \
+ from += amt; \
+ to += amt; \
+ count -= amt; \
+ } \
+} \
+static inline void shmem_memcpy_toio##s(volatile void __iomem *to, \
+ const void *from, \
+ size_t count) \
+{ \
+ while (count) { \
+ __raw_write##w(*(u##s *)from, to); \
+ from += amt; \
+ to += amt; \
+ count -= amt; \
+ } \
+} \
+static struct scmi_shmem_io_ops shmem_io_ops##s = { \
+ .fromio = shmem_memcpy_fromio##s, \
+ .toio = shmem_memcpy_toio##s, \
+};
WARNING: macros should not use a trailing semicolon
#94: FILE: drivers/firmware/arm_scmi/shmem.c:37:
+#define SHMEM_IO_OPS(w, s, amt) \
+static inline void shmem_memcpy_fromio##s(void *to, \
+ const volatile void __iomem *from, \
+ size_t count) \
+{ \
+ while (count) { \
+ *(u##s *)to = __raw_read##w(from); \
+ from += amt; \
+ to += amt; \
+ count -= amt; \
+ } \
+} \
+static inline void shmem_memcpy_toio##s(volatile void __iomem *to, \
+ const void *from, \
+ size_t count) \
+{ \
+ while (count) { \
+ __raw_write##w(*(u##s *)from, to); \
+ from += amt; \
+ to += amt; \
+ count -= amt; \
+ } \
+} \
+static struct scmi_shmem_io_ops shmem_io_ops##s = { \
+ .fromio = shmem_memcpy_fromio##s, \
+ .toio = shmem_memcpy_toio##s, \
+};
WARNING: Use of volatile is usually wrong: see Documentation/process/volatile-considered-harmful.rst
#96: FILE: drivers/firmware/arm_scmi/shmem.c:39:
+ const volatile void __iomem *from, \
WARNING: Use of volatile is usually wrong: see Documentation/process/volatile-considered-harmful.rst
#106: FILE: drivers/firmware/arm_scmi/shmem.c:49:
+static inline void shmem_memcpy_toio##s(volatile void __iomem *to, \
WARNING: Use of volatile is usually wrong: see Documentation/process/volatile-considered-harmful.rst
#128: FILE: drivers/firmware/arm_scmi/shmem.c:71:
+ const volatile void __iomem *from,
WARNING: Use of volatile is usually wrong: see Documentation/process/volatile-considered-harmful.rst
#134: FILE: drivers/firmware/arm_scmi/shmem.c:77:
+static inline void shmem_memcpy_toio(volatile void __iomem *to,
total: 0 errors, 7 warnings, 1 checks, 312 lines checked
NOTE: For some of the reported defects, checkpatch may be able to
mechanically convert to the typical style using --fix or --fix-inplace.
"[PATCH] firmware: arm_scmi: Support 'reg-io-width' property for" has style problems, please review.
NOTE: If any of the errors are false positives, please report
them to the maintainer, see CHECKPATCH in MAINTAINERS.
---8<----
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