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Mon, 26 Nov 2018 02:07:29 -0600 Received: from DFLE101.ent.ti.com (10.64.6.22) by DFLE100.ent.ti.com (10.64.6.21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1591.10; Mon, 26 Nov 2018 02:07:28 -0600 Received: from dflp33.itg.ti.com (10.64.6.16) by DFLE101.ent.ti.com (10.64.6.22) with Microsoft SMTP Server (version=TLS1_0, cipher=TLS_RSA_WITH_AES_256_CBC_SHA) id 15.1.1591.10 via Frontend Transport; Mon, 26 Nov 2018 02:07:28 -0600 Received: from [192.168.2.6] (ileax41-snat.itg.ti.com [10.172.224.153]) by dflp33.itg.ti.com (8.14.3/8.13.8) with ESMTP id wAQ87Pui025056; Mon, 26 Nov 2018 02:07:26 -0600 Subject: Re: [RFC PATCH v2 05/15] usb:cdns3: Added DRD support To: Pawel Laszczak , "devicetree@vger.kernel.org" References: <1542535751-16079-1-git-send-email-pawell@cadence.com> <1542535751-16079-6-git-send-email-pawell@cadence.com> <5BF8140C.7000605@ti.com> CC: "gregkh@linuxfoundation.org" , "linux-usb@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Alan Douglas , "jbergsagel@ti.com" , "nsekhar@ti.com" , "nm@ti.com" , Suresh Punnoose , "peter.chen@nxp.com" , Pawel Jez , Rahul Kumar From: Roger Quadros Message-ID: <5BFBA9BC.20306@ti.com> Date: Mon, 26 Nov 2018 10:07:24 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Pawel, On 26/11/18 09:23, Pawel Laszczak wrote: > Hi Roger, > >> On 18/11/18 12:09, Pawel Laszczak wrote: >>> Patch adds supports for detecting Host/Device mode. >>> Controller has additional OTG register that allow >>> implement even whole OTG functionality. >>> At this moment patch adds support only for detecting >>> the appropriate mode based on strap pins and ID pin. >>> >>> Signed-off-by: Pawel Laszczak >>> --- >>> drivers/usb/cdns3/Makefile | 2 +- >>> drivers/usb/cdns3/core.c | 27 +++-- >>> drivers/usb/cdns3/drd.c | 229 +++++++++++++++++++++++++++++++++++++ >>> drivers/usb/cdns3/drd.h | 122 ++++++++++++++++++++ >>> 4 files changed, 372 insertions(+), 8 deletions(-) >>> create mode 100644 drivers/usb/cdns3/drd.c >>> create mode 100644 drivers/usb/cdns3/drd.h >>> >>> diff --git a/drivers/usb/cdns3/Makefile b/drivers/usb/cdns3/Makefile >>> index 02d25b23c5d3..e779b2a2f8eb 100644 >>> --- a/drivers/usb/cdns3/Makefile >>> +++ b/drivers/usb/cdns3/Makefile >>> @@ -1,5 +1,5 @@ >>> obj-$(CONFIG_USB_CDNS3) += cdns3.o >>> obj-$(CONFIG_USB_CDNS3_PCI_WRAP) += cdns3-pci.o >>> >>> -cdns3-y := core.o >>> +cdns3-y := core.o drd.o >>> cdns3-pci-y := cdns3-pci-wrap.o >>> diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c >>> index f9055d4da67f..dbee4325da7f 100644 >>> --- a/drivers/usb/cdns3/core.c >>> +++ b/drivers/usb/cdns3/core.c >>> @@ -17,6 +17,7 @@ >>> >>> #include "gadget.h" >>> #include "core.h" >>> +#include "drd.h" >>> >>> static inline struct cdns3_role_driver *cdns3_get_current_role_driver(struct cdns3 *cdns) >>> { >>> @@ -57,8 +58,10 @@ static inline void cdns3_role_stop(struct cdns3 *cdns) >>> static enum cdns3_roles cdns3_get_role(struct cdns3 *cdns) >>> { >>> if (cdns->roles[CDNS3_ROLE_HOST] && cdns->roles[CDNS3_ROLE_GADGET]) { >>> - //TODO: implements selecting device/host mode >>> - return CDNS3_ROLE_HOST; >>> + if (cdns3_is_host(cdns)) >>> + return CDNS3_ROLE_HOST; >>> + if (cdns3_is_device(cdns)) >>> + return CDNS3_ROLE_GADGET; >>> } >>> return cdns->roles[CDNS3_ROLE_HOST] >>> ? CDNS3_ROLE_HOST >>> @@ -124,6 +127,12 @@ static irqreturn_t cdns3_irq(int irq, void *data) >>> struct cdns3 *cdns = data; >>> irqreturn_t ret = IRQ_NONE; >>> >>> + if (cdns->dr_mode == USB_DR_MODE_OTG) { >>> + ret = cdns3_drd_irq(cdns); >>> + if (ret == IRQ_HANDLED) >>> + return ret; >>> + } >> >> The kernel's shared IRQ model takes care of sharing the same interrupt >> between different devices and their drivers. You don't need to manually >> handle it here. Just let all 3 drivers do a request_irq() and have >> handlers check if the IRQ was theirs or not and return IRQ_HANDLED or >> IRQ_NONE accordingly. >> >> Looks like you can do away with irq member of the role driver struct. > > Ok, I will split it into 3 separate part, but in this case, I additionally have to check the current > role in ISR function. Driver can't read host side registers when controller works in device role > and vice versa. One part of controller is kept in reset. Only DRD registers are common and are all accessible. > In which ISR do you need to check current role? I'm not sure if we are on the same page. Core (drd) driver shouldn't read host/device side registers. All 3 drivers, i.e. DRD(core), Host (xhci) and device (cdns3) should do a request_irq() and process their respective IRQ events. >>> + >>> /* Handle device/host interrupt */ >>> if (cdns->role != CDNS3_ROLE_END) >>> ret = cdns3_get_current_role_driver(cdns)->irq(cdns); >>> @@ -176,11 +185,8 @@ static void cdns3_role_switch(struct work_struct *work) >>> >>> cdns = container_of(work, struct cdns3, role_switch_wq); >>> >>> - //TODO: implements this functions. >>> - //host = cdns3_is_host(cdns); >>> - //device = cdns3_is_device(cdns); >>> - host = 1; >>> - device = 0; >>> + host = cdns3_is_host(cdns); >>> + device = cdns3_is_device(cdns); >> >> What if there is a ID transition between the 2 functions so that >> and both host and device become true? >> Since you are checking the ID level separately in both the functions. >> >> How about instead having cdns3_get_id() and using >> it to start/stop relevant roles if we are in OTG mode. >> >> Is this going to be used for a role switch even if we're not in OTG mode? >> If not then it is a BUG if we get here. >> > Good point. > User can change current mode by debugfs and then this function will also invoked. > Probably I use cdns3_get_id as you suggest. > >>> >>> if (host) >>> role = CDNS3_ROLE_HOST; >>> @@ -194,6 +200,12 @@ static void cdns3_role_switch(struct work_struct *work) >>> pm_runtime_get_sync(cdns->dev); >>> cdns3_role_stop(cdns); >>> >>> + if (cdns->desired_dr_mode != cdns->current_dr_mode) { >> >> This is about roles, why are we checking dr_mode here? > > Because after changing dr_mode by means of debugfs we need to update mode. > Driver should do this after stopping the previous role. I will move this condition > to cdns3_drd_update_mode and add comment in this place. > >> >>> + cdns3_drd_update_mode(cdns); >>> + host = cdns3_is_host(cdns); >>> + device = cdns3_is_device(cdns); >>> + } >>> + >>> if (host) { >>> if (cdns->roles[CDNS3_ROLE_HOST]) >>> cdns3_do_role_switch(cdns, CDNS3_ROLE_HOST); >>> @@ -287,6 +299,7 @@ static int cdns3_probe(struct platform_device *pdev) >>> if (ret) >>> goto err2; >>> >>> + ret = cdns3_drd_init(cdns); >>> if (ret) >>> goto err2; >>> >>> diff --git a/drivers/usb/cdns3/drd.c b/drivers/usb/cdns3/drd.c >>> new file mode 100644 >>> index 000000000000..ac741c80e776 >>> --- /dev/null >>> +++ b/drivers/usb/cdns3/drd.c >>> @@ -0,0 +1,229 @@ >>> +// SPDX-License-Identifier: GPL-2.0 >>> +/* >>> + * Cadence USBSS DRD Driver. >>> + * >>> + * Copyright (C) 2018 Cadence. >>> + * >>> + * Author: Pawel Laszczak >> + * >>> + */ >>> +#include >>> +#include >>> +#include >>> +#include >>> + >>> +#include "gadget.h" >>> +#include "drd.h" >>> + >>> +/** >>> + * cdns3_set_mode - change mode of OTG Core >>> + * @cdns: pointer to context structure >>> + * @mode: selected mode from cdns_role >>> + */ >>> +void cdns3_set_mode(struct cdns3 *cdns, enum usb_dr_mode mode) >>> +{ >>> + u32 reg; >>> + >>> + cdns->current_dr_mode = mode; >>> + switch (mode) { >>> + case USB_DR_MODE_PERIPHERAL: >>> + dev_info(cdns->dev, "Set controller to Gadget mode\n"); >>> + writel(OTGCMD_DEV_BUS_REQ | OTGCMD_OTG_DIS, >>> + &cdns->otg_regs->cmd); >>> + break; >>> + case USB_DR_MODE_HOST: >>> + dev_info(cdns->dev, "Set controller to Host mode\n"); >>> + writel(OTGCMD_HOST_BUS_REQ | OTGCMD_OTG_DIS, >>> + &cdns->otg_regs->cmd); >>> + break; >>> + case USB_DR_MODE_OTG: >>> + dev_info(cdns->dev, "Set controller to OTG mode\n"); >>> + reg = readl(&cdns->otg_regs->ctrl1); >>> + reg |= OTGCTRL1_IDPULLUP; >>> + writel(reg, &cdns->otg_regs->ctrl1); >>> + >>> + /* wait until valid ID (ID_VALUE) can be sampled (50ms). */ >>> + mdelay(50); >>> + break; >>> + default: >>> + cdns->current_dr_mode = USB_DR_MODE_UNKNOWN; >>> + dev_err(cdns->dev, "Unsupported mode of operation %d\n", mode); >>> + return; >>> + } >>> +} >>> + >>> +static int cdns3_otg_get_id(struct cdns3 *cdns) >>> +{ >>> + int id; >>> + >>> + id = readl(&cdns->otg_regs->sts) & OTGSTS_ID_VALUE; >>> + dev_dbg(cdns->dev, "OTG ID: %d", id); >>> + return id; >>> +} >>> + >>> +int cdns3_is_host(struct cdns3 *cdns) >>> +{ >>> + if (cdns->current_dr_mode == USB_DR_MODE_HOST) >>> + return 1; >> >> Why do you need this? > > I assumed that some SoC could have cut DRD /OTG and Device or Host part. > In such case the driver cannot be based on ID pin. > For only HOST it's not a problem because > the standard XHCI driver will be used. Probably I will remove this fragment. >> >>> + else if (cdns->current_dr_mode == USB_DR_MODE_OTG) >>> + if (!cdns3_otg_get_id(cdns)) >>> + return 1; >>> + >>> + return 0; >>> +} >>> + >>> +int cdns3_is_device(struct cdns3 *cdns) >>> +{ >>> + if (cdns->current_dr_mode == USB_DR_MODE_PERIPHERAL) >>> + return 1; >>> + else if (cdns->current_dr_mode == USB_DR_MODE_OTG) >>> + if (cdns3_otg_get_id(cdns)) >>> + return 1; >>> + >>> + return 0; >>> +} >>> + >>> +/** >>> + * cdns3_otg_disable_irq - Disable all OTG interrupts >>> + * @cdns: Pointer to controller context structure >>> + */ >>> +static void cdns3_otg_disable_irq(struct cdns3 *cdns) >>> +{ >>> + writel(0, &cdns->otg_regs->ien); >>> +} >>> + >>> +/** >>> + * cdns3_otg_enable_irq - enable id and sess_valid interrupts >>> + * @cdns: Pointer to controller context structure >>> + */ >>> +static void cdns3_otg_enable_irq(struct cdns3 *cdns) >>> +{ >>> + writel(OTGIEN_ID_CHANGE_INT | OTGIEN_VBUSVALID_RISE_INT | >>> + OTGIEN_VBUSVALID_FALL_INT, &cdns->otg_regs->ien); >>> +} >>> + >>> +/** >>> + * cdns3_init_otg_mode - initialize drd controller >>> + * @cdns: Pointer to controller context structure >>> + * >>> + * Returns 0 on success otherwise negative errno >>> + */ >>> +static void cdns3_init_otg_mode(struct cdns3 *cdns) >>> +{ >>> + cdns3_otg_disable_irq(cdns); >>> + /* clear all interrupts */ >>> + writel(~0, &cdns->otg_regs->ivect); >>> + >>> + cdns3_set_mode(cdns, USB_DR_MODE_OTG); >>> + >>> + cdns3_otg_enable_irq(cdns); >>> +} >>> + >>> +/** >>> + * cdns3_drd_update_mode - initialize mode of operation >> >> Looks like this will be called only once. How about calling it >> >> cdns3_drd_init_mode()? > > It will be also called after changing dr_mode from debugfs. > >>> + * @cdns: Pointer to controller context structure >>> + * >>> + * Returns 0 on success otherwise negative errno >>> + */ >>> +int cdns3_drd_update_mode(struct cdns3 *cdns) >>> +{ >>> + int ret = 0; >>> + >>> + switch (cdns->desired_dr_mode) { >> >> I think we can get rid of desired_dr_mode member in struct cdns. >> Just pass the mode as an argument to cdns3_drd_init_mode() > > This will be used also in patch that introduce debugfs. This filed is also used > during changing dr_mode from user space. > > My intention was: > dr_mode - indicated what driver can support, this filed based on dr_mode from device tree, > straps bits from otg register and kernel configuration. > desired_ dr_mode - the next mode desired by user, changed by debugfs > current_dr_mode - actually selected mode > OK, makes sense. But let's keep this patch simple. Add only the members you need right now. Introduce the new one (desired_dr_mode) in the debugfs patch. >> >> And we already have cdns->dr_mode. >> >>> + case USB_DR_MODE_PERIPHERAL: >>> + cdns3_set_mode(cdns, USB_DR_MODE_PERIPHERAL); >>> + break; >>> + case USB_DR_MODE_HOST: >>> + cdns3_set_mode(cdns, USB_DR_MODE_HOST); >>> + break; >>> + case USB_DR_MODE_OTG: >>> + cdns3_init_otg_mode(cdns); >>> + break; >>> + default: >>> + dev_err(cdns->dev, "Unsupported mode of operation %d\n", >>> + cdns->dr_mode); >>> + return -EINVAL; >>> + } >>> + >>> + return ret; >>> +} cheers, -roger -- Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki