From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="fDT5Mwnk" Received: from mail-qt1-x836.google.com (mail-qt1-x836.google.com [IPv6:2607:f8b0:4864:20::836]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2CF0110E2 for ; Thu, 30 Nov 2023 00:23:50 -0800 (PST) Received: by mail-qt1-x836.google.com with SMTP id d75a77b69052e-41cba6e8e65so3631951cf.2 for ; Thu, 30 Nov 2023 00:23:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1701332629; x=1701937429; darn=vger.kernel.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=QIzdnOff2PoZMygWcqyDE4rrb5xvAOPPEWo8BOB6JM8=; b=fDT5MwnkaS0xzh9Sy1fn+soBigBO0Ho97iYIEcmMAEkG0kVcfoUwrKr75rIPI9p392 E3JK0YQAf7OV4y3XU30G6YmyPXzszK8sKuIAR9qYBmHFwezK6MaU/p5cx0TQnaIHvhYd WbZZn3iHJdhps3yCjAjIjqpTEfWc5loE4UvQZFQ6Xq0sO4DtF/Lqy1hkrQrye9v4BfJ7 3aoG1Qt1AfGWBoVK4K+TSUo7yegRn+IPI1s+eynvLg4DpjKJr5QqdBZB2jEdXNrH9/I4 uVMacNDH/3DnTRs1az23ETX8JgreYLpj5QOzHyxMAvUDSdKwTbTKZzP1RcTrRPU9tTtP zebg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701332629; x=1701937429; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=QIzdnOff2PoZMygWcqyDE4rrb5xvAOPPEWo8BOB6JM8=; b=PtljET1FY1fdj6ZkrfbpGxjm6u3zzJgAlxF4rYKnXmkBpC4CXI3ZXUfMOZjc15C/xv ENm56YQQzjzfKY20bhPAej8j8tuTVHMQqVJ2u/XkOSYSjjbe/7FrlI8Y5YRp6JUF2pKC Fkzv0RGitiu1Z7oJOwRnwNlR7FgQjtaNB7khr0TMM0GmToeJ8Mvehys5z+Yj16/239ry aIZQ2bQX096DSXWURVmK5G4DB9GETqfiT15alJhhvevm5Y2+Nn6RmuRFL9eabxPR2EL0 7sycQITWirQHCjIPMusYSsZTMMjat8kCyQ214ZscYKNT/OW0Fa9yHuWBnb95fH1DOESH Dd6g== X-Gm-Message-State: AOJu0YzmjTqGeNwRRhZMyuFxsDD2nRw1FBM5nMkUAInXHkG4F+rW8UBC 3LbjSNOJKu62N9k3rpuhMjqI X-Google-Smtp-Source: AGHT+IFyHJ8goCrL1LNuM8zRCzGccnRCN7rW6OSWWSg4L7kH/z8/NKksqp+NfSIr35BrShINovXe0A== X-Received: by 2002:ac8:5d8c:0:b0:423:7b1e:e252 with SMTP id d12-20020ac85d8c000000b004237b1ee252mr23644018qtx.33.1701332629180; Thu, 30 Nov 2023 00:23:49 -0800 (PST) Received: from thinkpad ([59.92.100.237]) by smtp.gmail.com with ESMTPSA id i4-20020ac860c4000000b00423c95e5c44sm275594qtm.97.2023.11.30.00.23.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Nov 2023 00:23:48 -0800 (PST) Date: Thu, 30 Nov 2023 13:53:43 +0530 From: Manivannan Sadhasivam To: mhi@lists.linux.dev Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] bus: mhi: ep: Add support for interrupt moderation timer Message-ID: <20231130082343.GL3043@thinkpad> References: <20231026045513.12981-1-manivannan.sadhasivam@linaro.org> Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20231026045513.12981-1-manivannan.sadhasivam@linaro.org> On Thu, Oct 26, 2023 at 10:25:13AM +0530, Manivannan Sadhasivam wrote: > MHI spec defines the interrupt moderation timer feature using which the > host can limit the number of interrupts being raised for an event ring by > the device. This feature allows the host to process multiple event ring > elements by a single IRQ from the device, thereby eliminating the need to > process IRQ for each element. > > The INTMODT field in the event context array provides the value to be used > for delaying the IRQ generation from device. This value, along with the > Block Event Interrupt (BEI) flag of the TRE defines how IRQ is generated to > the host. > > Support for interrupt moderation timer is implemented using delayed > workqueue in kernel. And a separate delayed work item is used for each > event ring. > > Signed-off-by: Manivannan Sadhasivam Applied to mhi-next! - Mani > --- > > Changes in v2: > > * Fixed the build issue reported by Kbuild bot. > > drivers/bus/mhi/ep/internal.h | 3 +++ > drivers/bus/mhi/ep/main.c | 22 +++++++++++++++++++--- > drivers/bus/mhi/ep/ring.c | 19 ++++++++++++++++++- > 3 files changed, 40 insertions(+), 4 deletions(-) > > diff --git a/drivers/bus/mhi/ep/internal.h b/drivers/bus/mhi/ep/internal.h > index a2125fa5fe2f..8c5cf2b67951 100644 > --- a/drivers/bus/mhi/ep/internal.h > +++ b/drivers/bus/mhi/ep/internal.h > @@ -126,6 +126,7 @@ struct mhi_ep_ring { > union mhi_ep_ring_ctx *ring_ctx; > struct mhi_ring_element *ring_cache; > enum mhi_ep_ring_type type; > + struct delayed_work intmodt_work; > u64 rbase; > size_t rd_offset; > size_t wr_offset; > @@ -135,7 +136,9 @@ struct mhi_ep_ring { > u32 ch_id; > u32 er_index; > u32 irq_vector; > + u32 intmodt; > bool started; > + bool irq_pending; > }; > > struct mhi_ep_cmd { > diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c > index e2513f5f47a6..c06111045a84 100644 > --- a/drivers/bus/mhi/ep/main.c > +++ b/drivers/bus/mhi/ep/main.c > @@ -54,11 +54,27 @@ static int mhi_ep_send_event(struct mhi_ep_cntrl *mhi_cntrl, u32 ring_idx, > mutex_unlock(&mhi_cntrl->event_lock); > > /* > - * Raise IRQ to host only if the BEI flag is not set in TRE. Host might > - * set this flag for interrupt moderation as per MHI protocol. > + * As per the MHI specification, section 4.3, Interrupt moderation: > + * > + * 1. If BEI flag is not set, cancel any pending intmodt work if started > + * for the event ring and raise IRQ immediately. > + * > + * 2. If both BEI and intmodt are set, and if no IRQ is pending for the > + * same event ring, start the IRQ delayed work as per the value of > + * intmodt. If previous IRQ is pending, then do nothing as the pending > + * IRQ is enough for the host to process the current event ring element. > + * > + * 3. If BEI is set and intmodt is not set, no need to raise IRQ. > */ > - if (!bei) > + if (!bei) { > + if (READ_ONCE(ring->irq_pending)) > + cancel_delayed_work(&ring->intmodt_work); > + > mhi_cntrl->raise_irq(mhi_cntrl, ring->irq_vector); > + } else if (ring->intmodt && !READ_ONCE(ring->irq_pending)) { > + WRITE_ONCE(ring->irq_pending, true); > + schedule_delayed_work(&ring->intmodt_work, msecs_to_jiffies(ring->intmodt)); > + } > > return 0; > > diff --git a/drivers/bus/mhi/ep/ring.c b/drivers/bus/mhi/ep/ring.c > index 115518ec76a4..a1071c13761b 100644 > --- a/drivers/bus/mhi/ep/ring.c > +++ b/drivers/bus/mhi/ep/ring.c > @@ -157,6 +157,15 @@ void mhi_ep_ring_init(struct mhi_ep_ring *ring, enum mhi_ep_ring_type type, u32 > } > } > > +static void mhi_ep_raise_irq(struct work_struct *work) > +{ > + struct mhi_ep_ring *ring = container_of(work, struct mhi_ep_ring, intmodt_work.work); > + struct mhi_ep_cntrl *mhi_cntrl = ring->mhi_cntrl; > + > + mhi_cntrl->raise_irq(mhi_cntrl, ring->irq_vector); > + WRITE_ONCE(ring->irq_pending, false); > +} > + > int mhi_ep_ring_start(struct mhi_ep_cntrl *mhi_cntrl, struct mhi_ep_ring *ring, > union mhi_ep_ring_ctx *ctx) > { > @@ -173,8 +182,13 @@ int mhi_ep_ring_start(struct mhi_ep_cntrl *mhi_cntrl, struct mhi_ep_ring *ring, > if (ring->type == RING_TYPE_CH) > ring->er_index = le32_to_cpu(ring->ring_ctx->ch.erindex); > > - if (ring->type == RING_TYPE_ER) > + if (ring->type == RING_TYPE_ER) { > ring->irq_vector = le32_to_cpu(ring->ring_ctx->ev.msivec); > + ring->intmodt = FIELD_GET(EV_CTX_INTMODT_MASK, > + le32_to_cpu(ring->ring_ctx->ev.intmod)); > + > + INIT_DELAYED_WORK(&ring->intmodt_work, mhi_ep_raise_irq); > + } > > /* During ring init, both rp and wp are equal */ > memcpy_fromio(&val, (void __iomem *) &ring->ring_ctx->generic.rp, sizeof(u64)); > @@ -201,6 +215,9 @@ int mhi_ep_ring_start(struct mhi_ep_cntrl *mhi_cntrl, struct mhi_ep_ring *ring, > > void mhi_ep_ring_reset(struct mhi_ep_cntrl *mhi_cntrl, struct mhi_ep_ring *ring) > { > + if (ring->type == RING_TYPE_ER) > + cancel_delayed_work_sync(&ring->intmodt_work); > + > ring->started = false; > kfree(ring->ring_cache); > ring->ring_cache = NULL; > > base-commit: 12606ba1d46b34a241eb3d0956727e5379f0f626 > -- > 2.25.1 > -- மணிவண்ணன் சதாசிவம்