usb: host: ohci-at91: add support to enter suspend using SMC

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.

Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Link: https://lore.kernel.org/r/20220607133454.727063-1-clement.leger@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
index a24aea3..9832646 100644 (file)
--- 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);