From: Greg KH <gregkh@linuxfoundation.org> To: Wesley Cheng <quic_wcheng@quicinc.com> Cc: srinivas.kandagatla@linaro.org, mathias.nyman@intel.com, perex@perex.cz, broonie@kernel.org, lgirdwood@gmail.com, andersson@kernel.org, krzysztof.kozlowski+dt@linaro.org, Thinh.Nguyen@synopsys.com, bgoswami@quicinc.com, tiwai@suse.com, robh+dt@kernel.org, agross@kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, alsa-devel@alsa-project.org, devicetree@vger.kernel.org, linux-usb@vger.kernel.org, quic_jackp@quicinc.com, quic_plai@quicinc.com Subject: Re: [RFC PATCH 06/14] usb: core: hcd: Introduce USB HCD APIs for interrupter management Date: Sat, 24 Dec 2022 09:54:44 +0100 [thread overview] Message-ID: <Y6a+VJ75lRIUE9yD@kroah.com> (raw) In-Reply-To: <20221223233200.26089-7-quic_wcheng@quicinc.com> On Fri, Dec 23, 2022 at 03:31:52PM -0800, Wesley Cheng wrote: > For USB HCDs that can support multiple USB interrupters, expose functions > that class drivers can utilize for setting up secondary interrupters. > Class drivers can pass this information to its respective clients, i.e. > a dedicated DSP. Where is the locking here that seems to be required when a hcd is removed from the system and you have data in flight? What am I missing here in the design of this? And yes, HCDs get removed all the time, and will happen more and more in the future with the design of more systems moving to Thunderbolt/PCIe designs due to the simplicity of it. > +/** > + * usb_set_interruper - Reserve an interrupter Where is an "interrupter" defined? I don't know what this term means sorry, is this in the USB specification somewhere? > + * @udev: usb device which requested the interrupter > + * @intr_num: interrupter number to reserve > + * @dma: iova address to event ring > + * > + * Request for a specific interrupter to be reserved for a USB class driver. > + * This will return the base address to the event ring that was allocated to > + * the specific interrupter. > + **/ > +phys_addr_t usb_set_interruper(struct usb_device *udev, int intr_num, > + dma_addr_t *dma) > +{ > + struct usb_hcd *hcd; > + phys_addr_t pa = 0; > + > + hcd = bus_to_hcd(udev->bus); > + if (hcd->driver->update_interrupter) > + pa = hcd->driver->update_interrupter(hcd, intr_num, dma); > + > + return pa; Wait, you return a physical address? What are you going to do with that? And what guarantees that the address is valid after you return it (again, remember memory and devices can be removed at any point in time. thanks, greg k-h
WARNING: multiple messages have this Message-ID (diff)
From: Greg KH <gregkh@linuxfoundation.org> To: Wesley Cheng <quic_wcheng@quicinc.com> Cc: devicetree@vger.kernel.org, alsa-devel@alsa-project.org, linux-usb@vger.kernel.org, bgoswami@quicinc.com, mathias.nyman@intel.com, Thinh.Nguyen@synopsys.com, andersson@kernel.org, tiwai@suse.com, lgirdwood@gmail.com, robh+dt@kernel.org, broonie@kernel.org, srinivas.kandagatla@linaro.org, agross@kernel.org, krzysztof.kozlowski+dt@linaro.org, linux-arm-msm@vger.kernel.org, quic_plai@quicinc.com, linux-kernel@vger.kernel.org, quic_jackp@quicinc.com Subject: Re: [RFC PATCH 06/14] usb: core: hcd: Introduce USB HCD APIs for interrupter management Date: Sat, 24 Dec 2022 09:54:44 +0100 [thread overview] Message-ID: <Y6a+VJ75lRIUE9yD@kroah.com> (raw) In-Reply-To: <20221223233200.26089-7-quic_wcheng@quicinc.com> On Fri, Dec 23, 2022 at 03:31:52PM -0800, Wesley Cheng wrote: > For USB HCDs that can support multiple USB interrupters, expose functions > that class drivers can utilize for setting up secondary interrupters. > Class drivers can pass this information to its respective clients, i.e. > a dedicated DSP. Where is the locking here that seems to be required when a hcd is removed from the system and you have data in flight? What am I missing here in the design of this? And yes, HCDs get removed all the time, and will happen more and more in the future with the design of more systems moving to Thunderbolt/PCIe designs due to the simplicity of it. > +/** > + * usb_set_interruper - Reserve an interrupter Where is an "interrupter" defined? I don't know what this term means sorry, is this in the USB specification somewhere? > + * @udev: usb device which requested the interrupter > + * @intr_num: interrupter number to reserve > + * @dma: iova address to event ring > + * > + * Request for a specific interrupter to be reserved for a USB class driver. > + * This will return the base address to the event ring that was allocated to > + * the specific interrupter. > + **/ > +phys_addr_t usb_set_interruper(struct usb_device *udev, int intr_num, > + dma_addr_t *dma) > +{ > + struct usb_hcd *hcd; > + phys_addr_t pa = 0; > + > + hcd = bus_to_hcd(udev->bus); > + if (hcd->driver->update_interrupter) > + pa = hcd->driver->update_interrupter(hcd, intr_num, dma); > + > + return pa; Wait, you return a physical address? What are you going to do with that? And what guarantees that the address is valid after you return it (again, remember memory and devices can be removed at any point in time. thanks, greg k-h
next prev parent reply other threads:[~2022-12-24 8:54 UTC|newest] Thread overview: 171+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-12-23 23:31 [RFC PATCH 00/14] Introduce QC USB SND audio offloading support Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-23 23:31 ` [RFC PATCH 01/14] ASoC: Add SOC USB APIs for adding an USB backend Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 6:48 ` Greg KH 2022-12-24 6:48 ` Greg KH 2022-12-23 23:31 ` [RFC PATCH 02/14] ASoC: qcom: qdsp6: Introduce USB AFE port to q6dsp Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 1:37 ` kernel test robot 2023-01-04 23:33 ` Pierre-Louis Bossart 2023-01-06 1:05 ` Wesley Cheng 2023-01-06 1:05 ` Wesley Cheng 2023-01-06 16:09 ` Pierre-Louis Bossart 2023-01-07 0:51 ` Wesley Cheng 2023-01-07 0:51 ` Wesley Cheng 2023-01-05 18:09 ` Krzysztof Kozlowski 2023-01-05 18:09 ` Krzysztof Kozlowski 2023-01-06 1:32 ` Wesley Cheng 2023-01-06 1:32 ` Wesley Cheng 2022-12-23 23:31 ` [RFC PATCH 03/14] ASoC: qcom: Add USB backend ASoC driver for Q6 Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 2:17 ` kernel test robot 2022-12-24 2:17 ` kernel test robot 2022-12-24 9:02 ` Greg KH 2022-12-24 9:02 ` Greg KH 2022-12-27 13:04 ` Mark Brown 2022-12-27 13:04 ` Mark Brown 2022-12-27 13:45 ` Greg KH 2022-12-27 13:45 ` Greg KH 2022-12-27 14:02 ` Takashi Iwai 2022-12-27 14:02 ` Takashi Iwai 2022-12-27 14:11 ` Mark Brown 2022-12-27 14:11 ` Mark Brown 2022-12-27 15:11 ` Mark Brown 2022-12-27 15:11 ` Mark Brown 2022-12-27 21:06 ` Wesley Cheng 2022-12-27 21:06 ` Wesley Cheng 2022-12-27 21:07 ` Wesley Cheng 2022-12-27 21:07 ` Wesley Cheng 2023-01-04 23:41 ` Pierre-Louis Bossart 2023-01-06 1:05 ` Wesley Cheng 2023-01-06 1:05 ` Wesley Cheng 2023-01-06 16:16 ` Pierre-Louis Bossart 2022-12-23 23:31 ` [RFC PATCH 04/14] sound: usb: card: Introduce USB SND vendor op callbacks Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 11:03 ` Dmitry Baryshkov 2022-12-24 11:03 ` Dmitry Baryshkov 2022-12-27 21:07 ` Wesley Cheng 2022-12-27 21:07 ` Wesley Cheng 2022-12-27 21:33 ` Dmitry Baryshkov 2022-12-27 21:33 ` Dmitry Baryshkov 2022-12-29 13:49 ` Oliver Neukum 2022-12-29 13:49 ` Oliver Neukum 2022-12-29 14:20 ` Takashi Iwai 2022-12-29 14:20 ` Takashi Iwai 2022-12-30 7:10 ` Wesley Cheng 2022-12-30 7:10 ` Wesley Cheng 2023-01-03 12:20 ` Oliver Neukum 2023-01-03 12:20 ` Oliver Neukum 2023-01-03 12:49 ` Takashi Iwai 2023-01-03 12:49 ` Takashi Iwai 2023-01-03 23:45 ` Wesley Cheng 2023-01-03 23:45 ` Wesley Cheng 2022-12-23 23:31 ` [RFC PATCH 05/14] sound: usb: Export USB SND APIs for modules Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 6:48 ` Greg KH 2022-12-24 6:48 ` Greg KH 2022-12-23 23:31 ` [RFC PATCH 06/14] usb: core: hcd: Introduce USB HCD APIs for interrupter management Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 8:54 ` Greg KH [this message] 2022-12-24 8:54 ` Greg KH 2022-12-27 21:13 ` Wesley Cheng 2022-12-27 21:13 ` Wesley Cheng 2022-12-24 15:29 ` Alan Stern 2022-12-24 15:29 ` Alan Stern 2022-12-27 21:07 ` Wesley Cheng 2022-12-27 21:07 ` Wesley Cheng 2022-12-28 8:59 ` Oliver Neukum 2022-12-28 8:59 ` Oliver Neukum 2022-12-28 15:16 ` Alan Stern 2022-12-28 15:16 ` Alan Stern 2022-12-28 20:31 ` Wesley Cheng 2022-12-28 20:31 ` Wesley Cheng 2022-12-29 1:41 ` Alan Stern 2022-12-29 1:41 ` Alan Stern 2022-12-23 23:31 ` [RFC PATCH 07/14] usb: host: xhci: Add XHCI secondary interrupter support Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 5:59 ` kernel test robot 2022-12-24 8:55 ` Greg KH 2022-12-24 8:55 ` Greg KH 2022-12-28 15:47 ` Mathias Nyman 2022-12-28 15:47 ` Mathias Nyman 2022-12-29 21:14 ` Wesley Cheng 2022-12-29 21:14 ` Wesley Cheng 2023-01-02 16:38 ` Mathias Nyman 2023-01-02 16:38 ` Mathias Nyman 2023-01-09 20:24 ` Wesley Cheng 2023-01-09 20:24 ` Wesley Cheng 2023-01-10 19:47 ` Mathias Nyman 2023-01-10 19:47 ` Mathias Nyman 2023-01-10 20:03 ` Wesley Cheng 2023-01-10 20:03 ` Wesley Cheng 2023-01-11 3:11 ` Wesley Cheng 2023-01-11 3:11 ` Wesley Cheng 2023-01-12 9:24 ` Mathias Nyman 2023-01-12 9:24 ` Mathias Nyman 2023-01-13 0:34 ` Wesley Cheng 2023-01-13 0:34 ` Wesley Cheng 2022-12-23 23:31 ` [RFC PATCH 08/14] usb: dwc3: Add DT parameter to specify maximum number of interrupters Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 11:13 ` Dmitry Baryshkov 2022-12-24 11:13 ` Dmitry Baryshkov 2022-12-26 12:28 ` Krzysztof Kozlowski 2022-12-26 12:28 ` Krzysztof Kozlowski 2022-12-27 21:06 ` Wesley Cheng 2022-12-27 21:06 ` Wesley Cheng 2022-12-23 23:31 ` [RFC PATCH 09/14] sound: usb: Introduce QC USB SND offloading support Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 2:27 ` kernel test robot 2023-01-02 17:28 ` Takashi Iwai 2023-01-02 17:28 ` Takashi Iwai 2023-01-04 22:38 ` Wesley Cheng 2023-01-04 22:38 ` Wesley Cheng 2023-01-04 23:51 ` Pierre-Louis Bossart 2023-01-06 1:06 ` Wesley Cheng 2023-01-06 1:06 ` Wesley Cheng 2022-12-23 23:31 ` [RFC PATCH 10/14] sound: usb: card: Check for support for requested audio format Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 8:59 ` Greg KH 2022-12-24 8:59 ` Greg KH 2022-12-27 21:07 ` Wesley Cheng 2022-12-27 21:07 ` Wesley Cheng 2022-12-27 20:31 ` kernel test robot 2022-12-23 23:31 ` [RFC PATCH 11/14] sound: soc: soc-usb: Add PCM format check API for USB backend Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 2:17 ` kernel test robot 2022-12-24 2:17 ` kernel test robot 2022-12-23 23:31 ` [RFC PATCH 12/14] sound: soc: qcom: qusb6: Ensure PCM format is supported by USB audio device Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 8:19 ` Sergey Shtylyov 2022-12-24 8:19 ` Sergey Shtylyov 2022-12-24 8:50 ` Wesley Cheng 2022-12-24 8:50 ` Wesley Cheng 2023-01-03 17:44 ` Mark Brown 2023-01-03 17:44 ` Mark Brown 2022-12-23 23:31 ` [RFC PATCH 13/14] ASoC: dt-bindings: Add Q6USB backend bindings Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-26 12:25 ` Krzysztof Kozlowski 2022-12-26 12:25 ` Krzysztof Kozlowski 2022-12-23 23:32 ` [RFC PATCH 14/14] ASoC: dt-bindings: Update example for enabling USB offload on SM8250 Wesley Cheng 2022-12-23 23:32 ` Wesley Cheng 2022-12-26 12:27 ` Krzysztof Kozlowski 2022-12-26 12:27 ` Krzysztof Kozlowski 2023-01-03 17:46 ` Mark Brown 2023-01-03 17:46 ` Mark Brown 2023-01-05 18:09 ` Krzysztof Kozlowski 2023-01-05 18:09 ` Krzysztof Kozlowski 2023-01-04 0:46 ` Rob Herring 2023-01-04 0:46 ` Rob Herring 2022-12-24 6:45 ` [RFC PATCH 00/14] Introduce QC USB SND audio offloading support Greg KH 2022-12-24 6:45 ` Greg KH 2022-12-24 8:49 ` Wesley Cheng 2022-12-24 8:49 ` Wesley Cheng 2022-12-27 14:36 ` Mark Brown 2022-12-27 14:36 ` Mark Brown 2023-01-04 23:19 ` Pierre-Louis Bossart 2023-01-06 1:05 ` Wesley Cheng 2023-01-06 1:05 ` Wesley Cheng 2023-01-06 15:57 ` Pierre-Louis Bossart 2023-01-07 0:46 ` Wesley Cheng 2023-01-07 0:46 ` Wesley Cheng
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