From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752430AbbETLRX (ORCPT ); Wed, 20 May 2015 07:17:23 -0400 Received: from smarthost01a.mail.zen.net.uk ([212.23.1.1]:33861 "EHLO smarthost01a.mail.zen.net.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751272AbbETLRT (ORCPT ); Wed, 20 May 2015 07:17:19 -0400 Message-ID: <1432120636.3231.24.camel@linaro.org> Subject: Re: [PATCH v2 2/5] firmware: add support for ARM System Control and Power Interface(SCPI) protocol From: "Jon Medhurst (Tixy)" To: Sudeep Holla Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Liviu Dudau , Lorenzo Pieralisi , Jassi Brar Date: Wed, 20 May 2015 12:17:16 +0100 In-Reply-To: <1431618155-3132-3-git-send-email-sudeep.holla@arm.com> References: <1431618155-3132-1-git-send-email-sudeep.holla@arm.com> <1431618155-3132-3-git-send-email-sudeep.holla@arm.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.9-1+b1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Originating-smarthost01a-IP: [82.69.122.217] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2015-05-14 at 16:42 +0100, Sudeep Holla wrote: > This patch adds support for System Control and Power Interface (SCPI) > Message Protocol used between the Application Cores(AP) and the System > Control Processor(SCP). The MHU peripheral provides a mechanism for > inter-processor communication between SCP's M3 processor and AP. > > SCP offers control and management of the core/cluster power states, > various power domain DVFS including the core/cluster, certain system > clocks configuration, thermal sensors and many others. > > This protocol driver provides interface for all the client drivers using > SCPI to make use of the features offered by the SCP. > > Signed-off-by: Sudeep Holla > CC: Jassi Brar > Cc: Liviu Dudau > Cc: Lorenzo Pieralisi > Cc: Jon Medhurst (Tixy) > --- Sorry for the delay in looking at this. I have one nitpick below but anyway, here's a Reviewed-by: Jon Medhurst (Tixy) [...] > +++ b/drivers/firmware/arm_scpi.c [...] > +static void scpi_process_cmd(struct scpi_chan *ch, u32 cmd) > +{ > + unsigned long flags; > + struct scpi_xfer *t, *match = NULL; > + > + spin_lock_irqsave(&ch->rx_lock, flags); > + if (list_empty(&ch->rx_pending)) { > + spin_unlock_irqrestore(&ch->rx_lock, flags); > + return; > + } > + > + list_for_each_entry(t, &ch->rx_pending, node) > + if (CMD_XTRACT_UNIQ(t->cmd) == CMD_XTRACT_UNIQ(cmd)) { > + list_del(&t->node); > + match = t; > + break; > + } > + /* check if wait_for_completion is in progress or timed-out */ > + if (match && !completion_done(&match->done)) { > + struct scpi_shared_mem *mem = ch->rx_payload; > + int len = min(match->rx_len, CMD_SIZE(cmd)); > + > + match->status = le32_to_cpu(mem->status); > + memcpy_fromio(match->rx_buf, mem->payload, len); > + if (match->rx_len > len) rx_len is unsigned and len is signed and so I had to go refresh my memory from the C standard before I could convince myself that this if statement was OK. Might be clearer if len was unsigned, especially as it's the 'min' of two unsigned values. -- Tixy From mboxrd@z Thu Jan 1 00:00:00 1970 From: tixy@linaro.org (Jon Medhurst (Tixy)) Date: Wed, 20 May 2015 12:17:16 +0100 Subject: [PATCH v2 2/5] firmware: add support for ARM System Control and Power Interface(SCPI) protocol In-Reply-To: <1431618155-3132-3-git-send-email-sudeep.holla@arm.com> References: <1431618155-3132-1-git-send-email-sudeep.holla@arm.com> <1431618155-3132-3-git-send-email-sudeep.holla@arm.com> Message-ID: <1432120636.3231.24.camel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, 2015-05-14 at 16:42 +0100, Sudeep Holla wrote: > This patch adds support for System Control and Power Interface (SCPI) > Message Protocol used between the Application Cores(AP) and the System > Control Processor(SCP). The MHU peripheral provides a mechanism for > inter-processor communication between SCP's M3 processor and AP. > > SCP offers control and management of the core/cluster power states, > various power domain DVFS including the core/cluster, certain system > clocks configuration, thermal sensors and many others. > > This protocol driver provides interface for all the client drivers using > SCPI to make use of the features offered by the SCP. > > Signed-off-by: Sudeep Holla > CC: Jassi Brar > Cc: Liviu Dudau > Cc: Lorenzo Pieralisi > Cc: Jon Medhurst (Tixy) > --- Sorry for the delay in looking at this. I have one nitpick below but anyway, here's a Reviewed-by: Jon Medhurst (Tixy) [...] > +++ b/drivers/firmware/arm_scpi.c [...] > +static void scpi_process_cmd(struct scpi_chan *ch, u32 cmd) > +{ > + unsigned long flags; > + struct scpi_xfer *t, *match = NULL; > + > + spin_lock_irqsave(&ch->rx_lock, flags); > + if (list_empty(&ch->rx_pending)) { > + spin_unlock_irqrestore(&ch->rx_lock, flags); > + return; > + } > + > + list_for_each_entry(t, &ch->rx_pending, node) > + if (CMD_XTRACT_UNIQ(t->cmd) == CMD_XTRACT_UNIQ(cmd)) { > + list_del(&t->node); > + match = t; > + break; > + } > + /* check if wait_for_completion is in progress or timed-out */ > + if (match && !completion_done(&match->done)) { > + struct scpi_shared_mem *mem = ch->rx_payload; > + int len = min(match->rx_len, CMD_SIZE(cmd)); > + > + match->status = le32_to_cpu(mem->status); > + memcpy_fromio(match->rx_buf, mem->payload, len); > + if (match->rx_len > len) rx_len is unsigned and len is signed and so I had to go refresh my memory from the C standard before I could convince myself that this if statement was OK. Might be clearer if len was unsigned, especially as it's the 'min' of two unsigned values. -- Tixy