From: Greg KH <gregkh@linuxfoundation.org>
To: Jeffrey Hugo <jhugo@codeaurora.org>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
arnd@arndb.de, smohanad@codeaurora.org, kvalo@codeaurora.org,
bjorn.andersson@linaro.org, hemantk@codeaurora.org,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 05/16] bus: mhi: core: Add support for ringing channel/event ring doorbells
Date: Sat, 25 Jan 2020 14:46:31 +0100 [thread overview]
Message-ID: <20200125134631.GA3518689@kroah.com> (raw)
In-Reply-To: <beadf428-82db-c89f-22bc-983d7b907bb3@codeaurora.org>
On Fri, Jan 24, 2020 at 03:51:12PM -0700, Jeffrey Hugo wrote:
> > +struct mhi_event_ctxt {
> > + u32 reserved : 8;
> > + u32 intmodc : 8;
> > + u32 intmodt : 16;
> > + u32 ertype;
> > + u32 msivec;
> > +
> > + u64 rbase __packed __aligned(4);
> > + u64 rlen __packed __aligned(4);
> > + u64 rp __packed __aligned(4);
> > + u64 wp __packed __aligned(4);
> > +};
>
> This is the struct that is shared with the device, correct? Surely it needs
> to be packed then? Seems like you'd expect some padding between msivec and
> rbase on a 64-bit system otherwise, which is probably not intended.
>
> Also I strongly dislike bitfields in structures which are shared with
> another system since the C specification doesn't define how they are
> implemented, therefore you can run into issues where different compilers
> decide to implement the actual backing memory differently. I know its less
> convinent, but I would prefer the use of bitmasks for these fields.
You have to use bitmasks in order for all endian cpus to work properly
here, so that needs to be fixed.
Oh, and if these values are in hardware, then the correct types also
need to be used (i.e. __u32 and __u64).
good catch!
greg k-h
next prev parent reply other threads:[~2020-01-26 7:43 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-23 11:18 [PATCH 00/16] Add MHI bus support Manivannan Sadhasivam
2020-01-23 11:18 ` [PATCH 01/16] docs: Add documentation for MHI bus Manivannan Sadhasivam
2020-01-23 12:58 ` Arnd Bergmann
2020-01-23 13:10 ` Manivannan Sadhasivam
2020-01-23 13:19 ` Arnd Bergmann
2020-01-23 13:30 ` Manivannan Sadhasivam
2020-01-23 14:52 ` Jeffrey Hugo
2020-01-23 16:41 ` Jeffrey Hugo
2020-01-27 12:02 ` Manivannan Sadhasivam
2020-01-23 11:18 ` [PATCH 02/16] bus: mhi: core: Add support for registering MHI controllers Manivannan Sadhasivam
2020-01-23 11:33 ` Greg KH
2020-01-23 11:56 ` Manivannan Sadhasivam
2020-01-23 17:05 ` Jeffrey Hugo
2020-01-23 18:14 ` Greg KH
2020-01-26 23:58 ` Jeffrey Hugo
2020-01-28 7:19 ` Manivannan Sadhasivam
2020-01-27 11:56 ` Manivannan Sadhasivam
2020-01-27 14:52 ` Jeffrey Hugo
2020-01-28 6:37 ` Manivannan Sadhasivam
2020-01-28 7:24 ` Greg KH
2020-01-28 7:27 ` Manivannan Sadhasivam
2020-01-24 8:29 ` Greg KH
2020-01-24 14:24 ` Jeffrey Hugo
2020-01-24 17:47 ` Greg KH
2020-01-24 18:12 ` Jeffrey Hugo
2020-01-25 13:26 ` Greg KH
2020-01-26 21:00 ` Jeffrey Hugo
2020-01-27 7:02 ` Manivannan Sadhasivam
2020-01-27 7:11 ` Greg KH
2020-01-23 11:18 ` [PATCH 03/16] bus: mhi: core: Add support for registering MHI client drivers Manivannan Sadhasivam
2020-01-23 11:18 ` [PATCH 04/16] bus: mhi: core: Add support for creating and destroying MHI devices Manivannan Sadhasivam
2020-01-23 11:18 ` [PATCH 05/16] bus: mhi: core: Add support for ringing channel/event ring doorbells Manivannan Sadhasivam
2020-01-23 11:39 ` Arnd Bergmann
2020-01-23 12:00 ` Manivannan Sadhasivam
2020-01-23 12:44 ` Arnd Bergmann
2020-01-23 13:01 ` Manivannan Sadhasivam
2020-01-23 14:44 ` Jeffrey Hugo
2020-01-24 22:51 ` Jeffrey Hugo
2020-01-25 13:46 ` Greg KH [this message]
2020-01-27 7:10 ` Manivannan Sadhasivam
2020-01-27 7:21 ` Greg KH
2020-01-23 11:18 ` [PATCH 06/16] bus: mhi: core: Add support for PM state transitions Manivannan Sadhasivam
2020-01-23 11:18 ` [PATCH 07/16] bus: mhi: core: Add support for basic PM operations Manivannan Sadhasivam
2020-01-23 11:18 ` [PATCH 08/16] bus: mhi: core: Add support for downloading firmware over BHIe Manivannan Sadhasivam
2020-01-28 19:36 ` Jeffrey Hugo
2020-01-29 6:56 ` Manivannan Sadhasivam
2020-01-23 11:18 ` [PATCH 09/16] bus: mhi: core: Add support for downloading RDDM image during panic Manivannan Sadhasivam
2020-01-23 11:18 ` [PATCH 10/16] bus: mhi: core: Add support for processing events from client device Manivannan Sadhasivam
2020-01-23 11:18 ` [PATCH 11/16] bus: mhi: core: Add support for data transfer Manivannan Sadhasivam
2020-01-23 11:18 ` [PATCH 12/16] bus: mhi: core: Add uevent support for module autoloading Manivannan Sadhasivam
2020-01-23 11:18 ` [PATCH 13/16] MAINTAINERS: Add entry for MHI bus Manivannan Sadhasivam
2020-01-23 11:18 ` [PATCH 14/16] net: qrtr: Add MHI transport layer Manivannan Sadhasivam
2020-01-23 11:18 ` [PATCH 15/16] net: qrtr: Do not depend on ARCH_QCOM Manivannan Sadhasivam
2020-01-23 11:18 ` [PATCH 16/16] soc: qcom: Do not depend on ARCH_QCOM for QMI helpers Manivannan Sadhasivam
2020-01-23 11:45 ` Arnd Bergmann
2020-01-23 12:03 ` Manivannan Sadhasivam
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