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SubjectRe: [PATCH v2] usb: host: ohci-at91: add support to enter suspend using SMC
Date
On 07.06.2022 16:34, Clément Léger wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> When Linux is running under OP-TEE, the SFR is set as secured and thus
> the AT91_OHCIICR_USB_SUSPEND register isn't accessible. Add a SMC to
> do the appropriate call to suspend the controller.
> The SMC id is fetched from the device-tree property
> "microchip,suspend-smc-id". if present, then the syscon regmap is not
> used to enter suspend and a SMC is issued.
>
> Signed-off-by: Clément Léger <clement.leger@bootlin.com>

Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>


> ---
>
> Notes:
> Changes in V2:
> - Change check order in ohci_at91_port_suspend()
> - Renamed smc_id to suspend_smc_id for clarity
>
> drivers/usb/host/ohci-at91.c | 69 ++++++++++++++++++++++++------------
> 1 file changed, 46 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
> index a24aea3d2759..98326465e2dc 100644
> --- a/drivers/usb/host/ohci-at91.c
> +++ b/drivers/usb/host/ohci-at91.c
> @@ -13,6 +13,7 @@
> * This file is licenced under the GPL.
> */
>
> +#include <linux/arm-smccc.h>
> #include <linux/clk.h>
> #include <linux/dma-mapping.h>
> #include <linux/gpio/consumer.h>
> @@ -55,6 +56,7 @@ struct ohci_at91_priv {
> bool clocked;
> bool wakeup; /* Saved wake-up state for resume */
> struct regmap *sfr_regmap;
> + u32 suspend_smc_id;
> };
> /* interface and function clocks; sometimes also an AHB clock */
>
> @@ -135,6 +137,19 @@ static void at91_stop_hc(struct platform_device *pdev)
>
> static void usb_hcd_at91_remove (struct usb_hcd *, struct platform_device *);
>
> +static u32 at91_dt_suspend_smc(struct device *dev)
> +{
> + u32 suspend_smc_id;
> +
> + if (!dev->of_node)
> + return 0;
> +
> + if (of_property_read_u32(dev->of_node, "microchip,suspend-smc-id", &suspend_smc_id))
> + return 0;
> +
> + return suspend_smc_id;
> +}
> +
> static struct regmap *at91_dt_syscon_sfr(void)
> {
> struct regmap *regmap;
> @@ -215,9 +230,13 @@ static int usb_hcd_at91_probe(const struct hc_driver *driver,
> goto err;
> }
>
> - ohci_at91->sfr_regmap = at91_dt_syscon_sfr();
> - if (!ohci_at91->sfr_regmap)
> - dev_dbg(dev, "failed to find sfr node\n");
> + ohci_at91->suspend_smc_id = at91_dt_suspend_smc(dev);
> + if (!ohci_at91->suspend_smc_id) {
> + dev_dbg(dev, "failed to find sfr suspend smc id, using regmap\n");
> + ohci_at91->sfr_regmap = at91_dt_syscon_sfr();
> + if (!ohci_at91->sfr_regmap)
> + dev_dbg(dev, "failed to find sfr node\n");
> + }
>
> board = hcd->self.controller->platform_data;
> ohci = hcd_to_ohci(hcd);
> @@ -303,24 +322,30 @@ static int ohci_at91_hub_status_data(struct usb_hcd *hcd, char *buf)
> return length;
> }
>
> -static int ohci_at91_port_suspend(struct regmap *regmap, u8 set)
> +static int ohci_at91_port_suspend(struct ohci_at91_priv *ohci_at91, u8 set)
> {
> + struct regmap *regmap = ohci_at91->sfr_regmap;
> u32 regval;
> int ret;
>
> - if (!regmap)
> - return 0;
> + if (ohci_at91->suspend_smc_id) {
> + struct arm_smccc_res res;
>
> - ret = regmap_read(regmap, AT91_SFR_OHCIICR, &regval);
> - if (ret)
> - return ret;
> + arm_smccc_smc(ohci_at91->suspend_smc_id, set, 0, 0, 0, 0, 0, 0, &res);
> + if (res.a0)
> + return -EINVAL;
> + } else if (regmap) {
> + ret = regmap_read(regmap, AT91_SFR_OHCIICR, &regval);
> + if (ret)
> + return ret;
>
> - if (set)
> - regval |= AT91_OHCIICR_USB_SUSPEND;
> - else
> - regval &= ~AT91_OHCIICR_USB_SUSPEND;
> + if (set)
> + regval |= AT91_OHCIICR_USB_SUSPEND;
> + else
> + regval &= ~AT91_OHCIICR_USB_SUSPEND;
>
> - regmap_write(regmap, AT91_SFR_OHCIICR, regval);
> + regmap_write(regmap, AT91_SFR_OHCIICR, regval);
> + }
>
> return 0;
> }
> @@ -357,9 +382,8 @@ static int ohci_at91_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
>
> case USB_PORT_FEAT_SUSPEND:
> dev_dbg(hcd->self.controller, "SetPortFeat: SUSPEND\n");
> - if (valid_port(wIndex) && ohci_at91->sfr_regmap) {
> - ohci_at91_port_suspend(ohci_at91->sfr_regmap,
> - 1);
> + if (valid_port(wIndex)) {
> + ohci_at91_port_suspend(ohci_at91, 1);
> return 0;
> }
> break;
> @@ -400,9 +424,8 @@ static int ohci_at91_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
>
> case USB_PORT_FEAT_SUSPEND:
> dev_dbg(hcd->self.controller, "ClearPortFeature: SUSPEND\n");
> - if (valid_port(wIndex) && ohci_at91->sfr_regmap) {
> - ohci_at91_port_suspend(ohci_at91->sfr_regmap,
> - 0);
> + if (valid_port(wIndex)) {
> + ohci_at91_port_suspend(ohci_at91, 0);
> return 0;
> }
> break;
> @@ -630,10 +653,10 @@ ohci_hcd_at91_drv_suspend(struct device *dev)
> /* flush the writes */
> (void) ohci_readl (ohci, &ohci->regs->control);
> msleep(1);
> - ohci_at91_port_suspend(ohci_at91->sfr_regmap, 1);
> + ohci_at91_port_suspend(ohci_at91, 1);
> at91_stop_clock(ohci_at91);
> } else {
> - ohci_at91_port_suspend(ohci_at91->sfr_regmap, 1);
> + ohci_at91_port_suspend(ohci_at91, 1);
> }
>
> return ret;
> @@ -645,7 +668,7 @@ ohci_hcd_at91_drv_resume(struct device *dev)
> struct usb_hcd *hcd = dev_get_drvdata(dev);
> struct ohci_at91_priv *ohci_at91 = hcd_to_ohci_at91_priv(hcd);
>
> - ohci_at91_port_suspend(ohci_at91->sfr_regmap, 0);
> + ohci_at91_port_suspend(ohci_at91, 0);
>
> if (ohci_at91->wakeup)
> disable_irq_wake(hcd->irq);
> --
> 2.36.1
>

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