From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sudeep Holla Subject: Re: [PATCH v8 1/7] qcom: spm: Add Subsystem Power Manager driver Date: Thu, 09 Oct 2014 17:53:32 +0100 Message-ID: <5436BD8C.2050601@arm.com> References: <1412718106-17049-1-git-send-email-lina.iyer@linaro.org> <1412718106-17049-2-git-send-email-lina.iyer@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=WINDOWS-1252; format=flowed Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <1412718106-17049-2-git-send-email-lina.iyer-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Lina Iyer , "daniel.lezcano-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "khilman-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "sboyd-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org" , "galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org" , "linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" Cc: Sudeep Holla , Lorenzo Pieralisi , "msivasub-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: devicetree@vger.kernel.org On 07/10/14 22:41, Lina Iyer wrote: > SPM is a hardware block that controls the peripheral logic surrounding > the application cores (cpu/l$). When the core executes WFI instruction, > the SPM takes over the putting the core in low power state as > configured. The wake up for the SPM is an interrupt at the GIC, which > then completes the rest of low power mode sequence and brings the core > out of low power mode. > > The SPM has a set of control registers that configure the SPMs > individually based on the type of the core and the runtime conditions. > SPM is a finite state machine block to which a sequence is provided and > it interprets the bytes and executes them in sequence. Each low power > mode that the core can enter into is provided to the SPM as a sequence. > > Configure the SPM to set the core (cpu or L2) into its low power mode, > the index of the first command in the sequence is set in the SPM_CTL > register. When the core executes ARM wfi instruction, it triggers the > SPM state machine to start executing from that index. The SPM state > machine waits until the interrupt occurs and starts executing the rest > of the sequence until it hits the end of the sequence. The end of the > sequence jumps the core out of its low power mode. > > Based on work by: Mahesh Sivasubramanian , > Ai Li , Praveen Chidambaram > Original tree available at - > git://codeaurora.org/quic/la/kernel/msm-3.10.git > > Signed-off-by: Lina Iyer > --- > .../devicetree/bindings/arm/msm/qcom,saw2.txt | 31 ++- > drivers/soc/qcom/Kconfig | 8 + > drivers/soc/qcom/Makefile | 1 + > drivers/soc/qcom/spm.c | 223 +++++++++++++++++++++ > 4 files changed, 257 insertions(+), 6 deletions(-) > create mode 100644 drivers/soc/qcom/spm.c > [...] > + > +static struct spm_driver_data *spm_get_drv(struct platform_device *pdev) > +{ > + struct spm_driver_data *drv = NULL; > + struct device_node *cpu_node, *saw_node; > + u32 cpu; > + > + for_each_possible_cpu(cpu) { > + if (drv) > + break; > + cpu_node = of_get_cpu_node(cpu, NULL); I have not looked at the patch in detail, just this caught my attention as I removed most of these unnecessary parsing in ARM code. Unless you need this before topology_init, you need not parse DT to get cpu_node. You can use of_cpu_device_node_get instead. Regards, Sudeep -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html