From: Sudeep Holla <sudeep.holla@arm.com> To: Lina Iyer <ilina@codeaurora.org> Cc: Ulf Hansson <ulf.hansson@linaro.org>, Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>, Mark Rutland <mark.rutland@arm.com>, Linux ARM <linux-arm-kernel@lists.infradead.org>, "Rafael J . Wysocki" <rjw@rjwysocki.net>, Daniel Lezcano <daniel.lezcano@linaro.org>, "Raju P . L . S . S . S . N" <rplsssn@codeaurora.org>, Amit Kucheria <amit.kucheria@linaro.org>, Bjorn Andersson <bjorn.andersson@linaro.org>, Stephen Boyd <sboyd@kernel.org>, Niklas Cassel <niklas.cassel@linaro.org>, Tony Lindgren <tony@atomide.com>, Kevin Hilman <khilman@kernel.org>, Viresh Kumar <viresh.kumar@linaro.org>, Vincent Guittot <vincent.guittot@linaro.org>, Geert Uytterhoeven <geert+renesas@glider.be>, Souvik Chakravarty <souvik.chakravarty@arm.com>, Linux PM <linux-pm@vger.kernel.org>, linux-arm-msm <linux-arm-msm@vger.kernel.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Lina Iyer <lina.iyer@linaro.org>, Sudeep Holla <sudeep.holla@arm.com> Subject: Re: [PATCH 09/18] drivers: firmware: psci: Add support for PM domains using genpd Date: Fri, 19 Jul 2019 10:45:30 +0100 [thread overview] Message-ID: <20190719094530.GA15248@e107155-lin> (raw) In-Reply-To: <20190718175746.GE25567@codeaurora.org> On Thu, Jul 18, 2019 at 11:57:46AM -0600, Lina Iyer wrote: > On Thu, Jul 18 2019 at 07:19 -0600, Sudeep Holla wrote: [...] > > > > Yes 2 different issues here: > > 1. The direct assignment overwriting the value is problem which you agree. > > 2. The OR logic on it's own is bit not so clear from the specification. > > Since firmware authors need to be aware of this to make all these > > work. So it's not implicit, either we set this requirement in form > > of binding. We were also thinking of stating composite state in the > > DT, still just a thought, need to come up with examples/illustrations. > > > It is generally very obvious to firmware authors to map hardware > definitions to specific bits in the state param. If a cluster component > has more than on/off state, more bits are assigned to the define the > idle states of the component. While I completely agree that generally the firmware authors tend to assign a bit(s) to indicate a state, it not so evident from the PSCI specification. My worry is someone shouldn't come up with sequential numbering and expect this to work. I am fine with OR, but we need to document it somewhere so that we can point people so that the driver in the kernel is not expected to work with any other schema of numbering StateID that violates the assumption. > Addition is also an option, but there are enough bits compared to the > hardware components that we have in each state, that it hasn't been a > problem. > Yes, but with extended format, the StateType move to bit 30, and if we represent each individual state to indicate that bit correctly(I except everyone to so that and it shouldn't cause issue if we OR the parameters to get composite states), addition may cause issues. -- Regards, Sudeep
WARNING: multiple messages have this Message-ID (diff)
From: Sudeep Holla <sudeep.holla@arm.com> To: Lina Iyer <ilina@codeaurora.org> Cc: Mark Rutland <mark.rutland@arm.com>, Ulf Hansson <ulf.hansson@linaro.org>, Geert Uytterhoeven <geert+renesas@glider.be>, Tony Lindgren <tony@atomide.com>, Viresh Kumar <viresh.kumar@linaro.org>, Bjorn Andersson <bjorn.andersson@linaro.org>, Lina Iyer <lina.iyer@linaro.org>, Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>, Kevin Hilman <khilman@kernel.org>, Daniel Lezcano <daniel.lezcano@linaro.org>, "Raju P . L . S . S . S . N" <rplsssn@codeaurora.org>, Souvik Chakravarty <souvik.chakravarty@arm.com>, Linux PM <linux-pm@vger.kernel.org>, linux-arm-msm <linux-arm-msm@vger.kernel.org>, Linux ARM <linux-arm-kernel@lists.infradead.org>, Stephen Boyd <sboyd@kernel.org>, "Rafael J . Wysocki" <rjw@rjwysocki.net>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Amit Kucheria <amit.kucheria@linaro.org>, Sudeep Holla <sudeep.holla@arm.com>, Niklas Cassel <niklas.cassel@linaro.org> Subject: Re: [PATCH 09/18] drivers: firmware: psci: Add support for PM domains using genpd Date: Fri, 19 Jul 2019 10:45:30 +0100 [thread overview] Message-ID: <20190719094530.GA15248@e107155-lin> (raw) In-Reply-To: <20190718175746.GE25567@codeaurora.org> On Thu, Jul 18, 2019 at 11:57:46AM -0600, Lina Iyer wrote: > On Thu, Jul 18 2019 at 07:19 -0600, Sudeep Holla wrote: [...] > > > > Yes 2 different issues here: > > 1. The direct assignment overwriting the value is problem which you agree. > > 2. The OR logic on it's own is bit not so clear from the specification. > > Since firmware authors need to be aware of this to make all these > > work. So it's not implicit, either we set this requirement in form > > of binding. We were also thinking of stating composite state in the > > DT, still just a thought, need to come up with examples/illustrations. > > > It is generally very obvious to firmware authors to map hardware > definitions to specific bits in the state param. If a cluster component > has more than on/off state, more bits are assigned to the define the > idle states of the component. While I completely agree that generally the firmware authors tend to assign a bit(s) to indicate a state, it not so evident from the PSCI specification. My worry is someone shouldn't come up with sequential numbering and expect this to work. I am fine with OR, but we need to document it somewhere so that we can point people so that the driver in the kernel is not expected to work with any other schema of numbering StateID that violates the assumption. > Addition is also an option, but there are enough bits compared to the > hardware components that we have in each state, that it hasn't been a > problem. > Yes, but with extended format, the StateType move to bit 30, and if we represent each individual state to indicate that bit correctly(I except everyone to so that and it shouldn't cause issue if we OR the parameters to get composite states), addition may cause issues. -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-07-19 9:45 UTC|newest] Thread overview: 155+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-05-13 19:22 [PATCH 00/18] ARM/ARM64: Support hierarchical CPU arrangement for PSCI Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` [PATCH 01/18] dt: psci: Update DT bindings to support hierarchical PSCI states Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-07-19 11:29 ` Lorenzo Pieralisi 2019-07-19 11:29 ` Lorenzo Pieralisi 2019-05-13 19:22 ` [PATCH 02/18] of: base: Add of_get_cpu_state_node() to get idle states for a CPU node Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` [PATCH 03/18] cpuidle: dt: Support hierarchical CPU idle states Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` [PATCH 04/18] ARM/ARM64: cpuidle: Let back-end init ops take the driver as input Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-06-07 15:00 ` Sudeep Holla 2019-06-07 15:00 ` Sudeep Holla 2019-06-10 10:20 ` Ulf Hansson 2019-06-10 10:20 ` Ulf Hansson 2019-05-13 19:22 ` [PATCH 05/18] drivers: firmware: psci: Simplify state node parsing Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-06-07 15:01 ` Sudeep Holla 2019-06-07 15:01 ` Sudeep Holla 2019-05-13 19:22 ` [PATCH 06/18] drivers: firmware: psci: Support hierarchical CPU idle states Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-06-07 15:03 ` Sudeep Holla 2019-06-07 15:03 ` Sudeep Holla 2019-05-13 19:22 ` [PATCH 07/18] drivers: firmware: psci: Prepare to use OS initiated suspend mode Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-06-07 15:17 ` Sudeep Holla 2019-06-07 15:17 ` Sudeep Holla 2019-06-10 10:21 ` Ulf Hansson 2019-06-10 10:21 ` Ulf Hansson 2019-06-10 10:42 ` Sudeep Holla 2019-06-10 10:42 ` Sudeep Holla 2019-07-16 14:53 ` Sudeep Holla 2019-07-16 14:53 ` Sudeep Holla 2019-05-13 19:22 ` [PATCH 08/18] drivers: firmware: psci: Prepare to support PM domains Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-06-07 15:21 ` Sudeep Holla 2019-06-07 15:21 ` Sudeep Holla 2019-05-13 19:22 ` [PATCH 09/18] drivers: firmware: psci: Add support for PM domains using genpd Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-06-07 15:27 ` Sudeep Holla 2019-06-07 15:27 ` Sudeep Holla 2019-06-10 10:21 ` Ulf Hansson 2019-06-10 10:21 ` Ulf Hansson 2019-06-10 10:59 ` Sudeep Holla 2019-06-10 10:59 ` Sudeep Holla 2019-07-16 15:05 ` Sudeep Holla 2019-07-16 15:05 ` Sudeep Holla 2019-07-18 11:04 ` Ulf Hansson 2019-07-18 11:04 ` Ulf Hansson 2019-07-18 13:19 ` Sudeep Holla 2019-07-18 13:19 ` Sudeep Holla 2019-07-18 17:57 ` Lina Iyer 2019-07-18 17:57 ` Lina Iyer 2019-07-19 9:45 ` Sudeep Holla [this message] 2019-07-19 9:45 ` Sudeep Holla 2019-05-13 19:22 ` [PATCH 10/18] drivers: firmware: psci: Add hierarchical domain idle states converter Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-07-09 15:31 ` Lorenzo Pieralisi 2019-07-09 15:31 ` Lorenzo Pieralisi 2019-07-16 8:45 ` Ulf Hansson 2019-07-16 8:45 ` Ulf Hansson 2019-07-16 14:51 ` Lorenzo Pieralisi 2019-07-16 14:51 ` Lorenzo Pieralisi 2019-07-18 11:43 ` Ulf Hansson 2019-07-18 11:43 ` Ulf Hansson 2019-07-18 13:36 ` Lorenzo Pieralisi 2019-07-18 13:36 ` Lorenzo Pieralisi 2019-05-13 19:22 ` [PATCH 11/18] drivers: firmware: psci: Introduce psci_dt_topology_init() Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` [PATCH 12/18] drivers: firmware: psci: Add a helper to attach a CPU to its PM domain Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` [PATCH 13/18] drivers: firmware: psci: Attach the CPU's device " Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` [PATCH 14/18] drivers: firmware: psci: Manage runtime PM in the idle path for CPUs Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-07-16 15:53 ` Lorenzo Pieralisi 2019-07-16 15:53 ` Lorenzo Pieralisi 2019-07-18 10:35 ` Ulf Hansson 2019-07-18 10:35 ` Ulf Hansson 2019-07-18 13:30 ` Lorenzo Pieralisi 2019-07-18 13:30 ` Lorenzo Pieralisi 2019-07-18 16:54 ` Ulf Hansson 2019-07-18 16:54 ` Ulf Hansson 2019-07-18 17:41 ` Lina Iyer 2019-07-18 17:41 ` Lina Iyer 2019-07-18 21:49 ` Ulf Hansson 2019-07-18 21:49 ` Ulf Hansson 2019-07-19 10:02 ` Lorenzo Pieralisi 2019-07-19 10:02 ` Lorenzo Pieralisi 2019-05-13 19:22 ` [PATCH 15/18] drivers: firmware: psci: Support CPU hotplug for the hierarchical model Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-06-07 15:31 ` Sudeep Holla 2019-06-07 15:31 ` Sudeep Holla 2019-06-10 10:21 ` Ulf Hansson 2019-06-10 10:21 ` Ulf Hansson 2019-06-10 11:02 ` Sudeep Holla 2019-06-10 11:02 ` Sudeep Holla 2019-05-13 19:22 ` [PATCH 16/18] arm64: kernel: Respect the hierarchical CPU topology in DT for PSCI Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` [PATCH 17/18] arm64: dts: Convert to the hierarchical CPU topology layout for MSM8916 Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-05-13 19:22 ` Ulf Hansson 2019-07-16 14:47 ` Sudeep Holla 2019-07-16 14:47 ` Sudeep Holla 2019-07-16 20:36 ` Lina Iyer 2019-07-16 20:36 ` Lina Iyer 2019-07-17 17:18 ` Sudeep Holla 2019-07-17 17:18 ` Sudeep Holla 2019-05-13 19:23 ` [PATCH 18/18] arm64: dts: hikey: Convert to the hierarchical CPU topology layout Ulf Hansson 2019-05-13 19:23 ` Ulf Hansson 2019-05-13 19:23 ` Ulf Hansson 2019-07-16 14:47 ` Sudeep Holla 2019-07-16 14:47 ` Sudeep Holla 2019-07-18 10:48 ` Ulf Hansson 2019-07-18 10:48 ` Ulf Hansson 2019-07-18 13:11 ` Sudeep Holla 2019-07-18 13:11 ` Sudeep Holla 2019-05-14 8:08 ` [PATCH 00/18] ARM/ARM64: Support hierarchical CPU arrangement for PSCI Rafael J. Wysocki 2019-05-14 8:08 ` Rafael J. Wysocki 2019-05-14 8:08 ` Rafael J. Wysocki 2019-05-14 8:58 ` Ulf Hansson 2019-05-14 8:58 ` Ulf Hansson 2019-05-14 8:58 ` Ulf Hansson 2019-06-07 15:42 ` Sudeep Holla 2019-06-07 15:42 ` Sudeep Holla 2019-06-07 19:34 ` Bjorn Andersson 2019-06-07 19:34 ` Bjorn Andersson 2019-06-10 10:32 ` Sudeep Holla 2019-06-10 10:32 ` Sudeep Holla 2019-06-10 15:54 ` Ulf Hansson 2019-06-10 15:54 ` Ulf Hansson 2019-06-10 17:16 ` Lorenzo Pieralisi 2019-06-10 17:16 ` Lorenzo Pieralisi 2019-06-10 18:57 ` Ulf Hansson 2019-06-10 18:57 ` Ulf Hansson 2019-06-18 11:56 ` Ulf Hansson 2019-06-18 11:56 ` Ulf Hansson 2019-06-07 11:19 ` Ulf Hansson 2019-06-07 11:19 ` Ulf Hansson
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