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[175.34.8.244]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-13fab143a7csm33178004c88.4.2026.08.03.20.38.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 03 Aug 2026 20:38:40 -0700 (PDT) Message-ID: Date: Tue, 4 Aug 2026 13:38:30 +1000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 01/11] arm_mpam: let low level MSC accessors return an error To: Andre Przywara , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , Will Deacon , "Rafael J . Wysocki" , Len Brown , James Morse , Ben Horgan , Reinette Chatre , Fenghua Yu Cc: Jonathan Cameron , Srivathsa L Rao , Ganapatrao Kulkarni , Trilok Soni , Srinivas Ramana , Niyas Sait , Lee Trager , Ritwick Sharma , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20260731170324.2927758-1-andre.przywara@arm.com> <20260731170324.2927758-2-andre.przywara@arm.com> From: Gavin Shan In-Reply-To: <20260731170324.2927758-2-andre.przywara@arm.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: T2Ldiun05baMtu_mOQEmQ9xbyIZRwxFfGknx6ZJ79Xo_1785814721 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260803_203852_945455_2A757A73 X-CRM114-Status: GOOD ( 14.58 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 8/1/26 3:03 AM, Andre Przywara wrote: > The upcoming MPAM-Fb support does not use MMIO primitives to access an > MSC, but employs a shared-memory/doorbell based firmware protocol. > Its complexity means that it must be able to handle errors, whereas we > always assume an MMIO based MSC access succeeds today. > > Change the __mpam_read_reg() low level accessor function to return the > requested data through a pointer, and return an error code instead. > Also change the __mpam_write_reg() accessor function to return an error > code. At the moment this is always 0, so all error handling paths are > not exercised at the moment. This will change later when alternative > MSC access methods like MPAM-Fb are activated. > > Change all direct users of those MSC wrappers to comply with the new > prototypes, though the errors are not propagated all the way up yet. > > Signed-off-by: Andre Przywara > Reviewed-by: Jonathan Cameron > Reviewed-by: Ben Horgan > --- > drivers/resctrl/mpam_devices.c | 208 +++++++++++++++++++++------------ > 1 file changed, 134 insertions(+), 74 deletions(-) > Reviewed-by: Gavin Shan