RE: [EXT] [PATCH v3 2/3] scsi: ufs-qcom: Implement device_reset vops

["Bean Huo (beanhuo)" <beanhuo@micron.com>]

Hi, Bjorn
Sorry just saw your message.

You can use UIC command，through function ufshcd_send_uic_cmd( ) with UIC_CMD_DME_END_PT_RST command.

DME_ENDPOINTRESET: It is used when UFS host wants the UFS device to perform a reset.

//bean

>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
>> ><linux-scsi-owner@vger.kernel.org>
>> >On Behalf Of Bjorn Andersson
>> >Sent: Saturday, June 8, 2019 7:05 AM
>> >To: Rob Herring <robh+dt@kernel.org>; Mark Rutland
>> ><mark.rutland@arm.com>; Alim Akhtar <alim.akhtar@samsung.com>; Avri
>> >Altman <avri.altman@wdc.com>; Pedro Sousa
>> ><pedrom.sousa@synopsys.com>; James E.J. Bottomley
>> ><jejb@linux.ibm.com>; Martin K. Petersen <martin.petersen@oracle.com>
>> >Cc: Andy Gross <agross@kernel.org>; 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
>> ><subhashj@codeaurora.org>.
>> >
>> >Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
>> >---
>> >
>> >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 <linux/of.h>
>> > #include <linux/platform_device.h>
>> > #include <linux/phy/phy.h>
>> >+#include <linux/gpio/consumer.h>
>> > #include <linux/reset-controller.h>
>> >
>> > #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
>>