From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bjorn Andersson Subject: Re: [EXT] [PATCH v3 2/3] scsi: ufs-qcom: Implement device_reset vops Date: Tue, 11 Jun 2019 23:31:43 -0700 Message-ID: <20190612063143.GD22737@tuxbook-pro> References: <20190608050450.12056-1-bjorn.andersson@linaro.org> <20190608050450.12056-3-bjorn.andersson@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: "Bean Huo (beanhuo)" Cc: Rob Herring , Mark Rutland , Alim Akhtar , Avri Altman , Pedro Sousa , "James E.J. Bottomley" , "Martin K. Petersen" , Andy Gross , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-msm@vger.kernel.org" , "linux-scsi@vger.kernel.org" List-Id: devicetree@vger.kernel.org On Tue 11 Jun 09:08 PDT 2019, Bean Huo (beanhuo) wrote: > Hi, Bjorn > This HW reset is dedicated to QUALCOMM based platform case. > how about adding a SW reset as to be default reset routine if platform doesn't support HW reset? > Can you please advice how I perform such software reset? Regards, Bjorn > >-----Original Message----- > >From: linux-scsi-owner@vger.kernel.org > >On Behalf Of Bjorn Andersson > >Sent: Saturday, June 8, 2019 7:05 AM > >To: Rob Herring ; Mark Rutland > >; Alim Akhtar ; Avri > >Altman ; Pedro Sousa > >; James E.J. Bottomley ; > >Martin K. Petersen > >Cc: Andy Gross ; devicetree@vger.kernel.org; linux- > >kernel@vger.kernel.org; linux-arm-msm@vger.kernel.org; linux- > >scsi@vger.kernel.org > >Subject: [EXT] [PATCH v3 2/3] scsi: ufs-qcom: Implement device_reset vops > > > >The UFS_RESET pin on Qualcomm SoCs are controlled by TLMM and exposed > >through the GPIO framework. Acquire the device-reset GPIO and use this to > >implement the device_reset vops, to allow resetting the attached memory. > > > >Based on downstream support implemented by Subhash Jadavani > >. > > > >Signed-off-by: Bjorn Andersson > >--- > > > >Changes since v2: > >- Moved implementation to Qualcomm driver > > > > .../devicetree/bindings/ufs/ufshcd-pltfrm.txt | 2 ++ > > drivers/scsi/ufs/ufs-qcom.c | 32 +++++++++++++++++++ > > drivers/scsi/ufs/ufs-qcom.h | 4 +++ > > 3 files changed, 38 insertions(+) > > > >diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt > >b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt > >index a74720486ee2..d562d8b4919c 100644 > >--- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt > >+++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt > >@@ -54,6 +54,8 @@ Optional properties: > > PHY reset from the UFS controller. > > - resets : reset node register > > - reset-names : describe reset node register, the "rst" corresponds to > >reset the whole UFS IP. > >+- device-reset-gpios : A phandle and gpio specifier denoting the GPIO > >connected > >+ to the RESET pin of the UFS memory device. > > > > Note: If above properties are not defined it can be assumed that the supply > >regulators or clocks are always on. > >diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c index > >ea7219407309..efaf57ba618a 100644 > >--- a/drivers/scsi/ufs/ufs-qcom.c > >+++ b/drivers/scsi/ufs/ufs-qcom.c > >@@ -16,6 +16,7 @@ > > #include > > #include > > #include > >+#include > > #include > > > > #include "ufshcd.h" > >@@ -1141,6 +1142,15 @@ static int ufs_qcom_init(struct ufs_hba *hba) > > goto out_variant_clear; > > } > > > >+ host->device_reset = devm_gpiod_get_optional(dev, "device-reset", > >+ GPIOD_OUT_HIGH); > >+ if (IS_ERR(host->device_reset)) { > >+ err = PTR_ERR(host->device_reset); > >+ if (err != -EPROBE_DEFER) > >+ dev_err(dev, "failed to acquire reset gpio: %d\n", err); > >+ goto out_variant_clear; > >+ } > >+ > > err = ufs_qcom_bus_register(host); > > if (err) > > goto out_variant_clear; > >@@ -1546,6 +1556,27 @@ static void ufs_qcom_dump_dbg_regs(struct > >ufs_hba *hba) > > usleep_range(1000, 1100); > > } > > > >+/** > >+ * ufs_qcom_device_reset() - toggle the (optional) device reset line > >+ * @hba: per-adapter instance > >+ * > >+ * Toggles the (optional) reset line to reset the attached device. > >+ */ > >+static void ufs_qcom_device_reset(struct ufs_hba *hba) { > >+ struct ufs_qcom_host *host = ufshcd_get_variant(hba); > >+ > >+ /* > >+ * The UFS device shall detect reset pulses of 1us, sleep for 10us to > >+ * be on the safe side. > >+ */ > >+ gpiod_set_value_cansleep(host->device_reset, 1); > >+ usleep_range(10, 15); > >+ > >+ gpiod_set_value_cansleep(host->device_reset, 0); > >+ usleep_range(10, 15); > >+} > >+ > > /** > > * struct ufs_hba_qcom_vops - UFS QCOM specific variant operations > > * > >@@ -1566,6 +1597,7 @@ static struct ufs_hba_variant_ops > >ufs_hba_qcom_vops = { > > .suspend = ufs_qcom_suspend, > > .resume = ufs_qcom_resume, > > .dbg_register_dump = ufs_qcom_dump_dbg_regs, > >+ .device_reset = ufs_qcom_device_reset, > > }; > > > > /** > >diff --git a/drivers/scsi/ufs/ufs-qcom.h b/drivers/scsi/ufs/ufs-qcom.h index > >68a880185752..b96ffb6804e4 100644 > >--- a/drivers/scsi/ufs/ufs-qcom.h > >+++ b/drivers/scsi/ufs/ufs-qcom.h > >@@ -204,6 +204,8 @@ struct ufs_qcom_testbus { > > u8 select_minor; > > }; > > > >+struct gpio_desc; > >+ > > struct ufs_qcom_host { > > /* > > * Set this capability if host controller supports the QUniPro mode > >@@ -241,6 +243,8 @@ struct ufs_qcom_host { > > struct ufs_qcom_testbus testbus; > > > > struct reset_controller_dev rcdev; > >+ > >+ struct gpio_desc *device_reset; > > }; > > > > static inline u32 > >-- > >2.18.0 >