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Tue, 21 Jul 2026 11:07:31 -0700 (PDT) X-Received: by 2002:a05:6a20:6a0a:b0:3c3:8041:89f5 with SMTP id adf61e73a8af0-3c3ad9e597fmr23899525637.66.1784657251224; Tue, 21 Jul 2026 11:07:31 -0700 (PDT) Received: from [192.168.1.8] ([106.222.235.145]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-3147e088d3fsm908106eec.25.2026.07.21.11.07.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 21 Jul 2026 11:07:30 -0700 (PDT) Message-ID: Date: Tue, 21 Jul 2026 23:37:21 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v23 06/14] dmaengine: qcom: bam_dma: add support for BAM locking To: Bartosz Golaszewski , Vinod Koul , Jonathan Corbet , Thara Gopinath , Herbert Xu , "David S. Miller" , Udit Tiwari , Md Sadre Alam , Dmitry Baryshkov , Manivannan Sadhasivam , Stephan Gerhold , Bjorn Andersson , Peter Ujfalusi , Michal Simek , Frank Li , Andy Gross , Neil Armstrong , Vignesh Raghavendra Cc: dmaengine@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, brgl@kernel.org, Bartosz Golaszewski References: <20260721-qcom-qce-cmd-descr-v23-0-1be02deffda9@oss.qualcomm.com> <20260721-qcom-qce-cmd-descr-v23-6-1be02deffda9@oss.qualcomm.com> Content-Language: en-US From: Mukesh Savaliya In-Reply-To: <20260721-qcom-qce-cmd-descr-v23-6-1be02deffda9@oss.qualcomm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Authority-Analysis: v=2.4 cv=I4JVgtgg c=1 sm=1 tr=0 ts=6a5fb564 cx=c_pps a=Oh5Dbbf/trHjhBongsHeRQ==:117 a=nYgDJefOb7ZtON2RxEtQrg==:17 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=_K5XuSEh1TEqbUxoQ0s3:22 a=5tee5T0z8aEC-XiIPRgA:9 a=QEXdDO2ut3YA:10 a=_Vgx9l1VpLgwpw_dHYaR:22 X-Proofpoint-ORIG-GUID: k0rriTzPpkMGNVqiZEwF9dXxiXNEn9_x X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzIxMDE5MSBTYWx0ZWRfXxqWdCm5+nJyY 4jIrmRMfXZNLXueP6+M9tc73qfiIbbHVdlKCsYBVdmpfF1PhPAh3SfXeNT3GHAx8KVfRGYIqM28 eCabShAXb7K9cMRJL080NLUuS0b/yBYunYX2RJaQW88mCYspzWJP0G2yeI1YjI/Yrl2FrJOskwM dpQwPGteCew4WvzrY/kgegj0P4/CgG9ckViO5dOjtuSvLxz7D4K965OLtbi4ay9yKJbm6n/5Sn3 ovE1yl6KqIwTF0b+oK5PvF5cMsq8qwNUX9SL8S2Sj+Sa6OYozaTpr1uZ7ZDIfZUIc18cByV6w7C GGQ0fwCKoS9XsjelXQBltxBY+6hHV5UGP3rSEE/ClFmQhj0nwHJFyvD72SQsTyJMw80J5SbYqZj 4YKWP7gx4wAwmkIaUe/MM1VXZSDTZ1WYM2qAxRXMG0dIpTyOF27tkmZFwBWwV0aYqgFb+PvdAi2 xexa5arpidD29L8iVbQ== X-Proofpoint-Spam-Info: AW1haW4tMjYwNzIxMDE5MSBTYWx0ZWRfX5Ef/JB42oDje 1Noyff4uWyL6OQ0+4ltzd0yUC+MB/IunXIJBKitZW5oIa/c0raVOEZ31/IaIlqClgz0/emEQMgB kBwkp8TVbJsCBxz9077AMfVP3Q69Auk= X-Proofpoint-GUID: k0rriTzPpkMGNVqiZEwF9dXxiXNEn9_x X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-21_03,2026-07-21_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 spamscore=0 lowpriorityscore=0 malwarescore=0 adultscore=0 priorityscore=1501 phishscore=0 bulkscore=0 suspectscore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607210191 Hi Bartosz, On 7/21/2026 7:03 PM, Bartosz Golaszewski wrote: [...] > @@ -676,13 +691,26 @@ static void bam_free_chan(struct dma_chan *chan) > static int bam_slave_config(struct dma_chan *chan, > struct dma_slave_config *cfg) > { > + struct bam_config *peripheral_cfg = cfg->peripheral_config; > struct bam_chan *bchan = to_bam_chan(chan); > + const struct bam_device_data *bdata = bchan->bdev->dev_data; > > guard(spinlock_irqsave)(&bchan->vc.lock); > > memcpy(&bchan->slave, cfg, sizeof(*cfg)); > bchan->reconfigure = 1; > > + /* > + * This is required to setup the pipe locking and must be done even > + * before the first call to bam_start_dma(). > + */ > + if (bdata->pipe_lock_supported && peripheral_cfg) { > + if (cfg->direction != DMA_MEM_TO_DEV) > + return -EINVAL; > + > + bchan->lock_scratchpad_addr = peripheral_cfg->lock_scratchpad_addr; IIUC, peripheral_cfg will be filled by the client driver of BAM right ? if not, who actually passes it ? > + } > + > return 0; > } > > @@ -802,6 +830,7 @@ static int bam_dma_terminate_all(struct dma_chan *chan) > } [...] > static void bam_start_dma(struct bam_chan *bchan) > { > - struct virt_dma_desc *vd = vchan_next_desc(&bchan->vc); > + struct virt_dma_desc *vd; > struct bam_device *bdev = bchan->bdev; > struct bam_async_desc *async_desc = NULL; > struct bam_desc_hw *desc; > @@ -1064,6 +1197,7 @@ static void bam_start_dma(struct bam_chan *bchan) > > lockdep_assert_held(&bchan->vc.lock); > > + vd = vchan_next_desc(&bchan->vc); > if (!vd) > return; > > @@ -1072,6 +1206,24 @@ static void bam_start_dma(struct bam_chan *bchan) > return; > > while (vd && !IS_BUSY(bchan)) { > + /* > + * Open a LOCK/UNLOCK bracket around each fresh sequence. > + * Sentinels inserted by bam_setup_pipe_lock() are skipped: they > + * already have bam_locked set and must not trigger a second pair. > + */ > + if (!bchan->bam_locked) { > + ret = bam_setup_pipe_lock(bchan); Hence, overall you meant to lock bam pipe once during the starting of the bam dma engine ? is it ? > + if (ret) { > + dev_err_ratelimited(bdev->dev, > + "failed to setup the pipe lock, deferring transfer: %d\n", > + ret); > + queue_work(system_bh_highpri_wq, &bdev->work); > + break; > + } > + if (bchan->bam_locked) > + vd = vchan_next_desc(&bchan->vc); > + } > + > list_del(&vd->node); > > async_desc = container_of(vd, struct bam_async_desc, vd); > @@ -1133,6 +1285,10 @@ static void bam_start_dma(struct bam_chan *bchan) > bchan->tail += async_desc->xfer_len; > bchan->tail %= MAX_DESCRIPTORS; > list_add_tail(&async_desc->desc_node, &bchan->desc_list); > + > + if (async_desc->is_lock_desc && > + (le16_to_cpu(async_desc->desc->flags) & DESC_FLAG_UNLOCK)) > + bchan->bam_locked = false; > } > [...]