Re: [PATCH 2/2] ehci: msm: bring up iface + core clocks

[Caleb Connolly]

On 02/05/2024 15:16, Sam Day wrote:

This seems to be necessary on my samsung-a5. Without this patch, the
first access of EHCI registers causes a bus stall and subsequent reset.

I am unsure why this wasn't already necessary for db410c, perhaps those
clocks are already enabled on boot.

Signed-off-by: Sam Day <m...@samcday.com>
---
  drivers/usb/host/ehci-msm.c | 37 +++++++++++++++++++++++++++++++++++--
  1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/ehci-msm.c b/drivers/usb/host/ehci-msm.c
index 98fe7bc3bc..b2e294dd64 100644
--- a/drivers/usb/host/ehci-msm.c
+++ b/drivers/usb/host/ehci-msm.c
@@ -7,8 +7,10 @@
   * Based on Linux driver
   */

+#include <clk.h>

  #include <common.h>
  #include <dm.h>
+#include <dm/device_compat.h>
  #include <dm/lists.h>
  #include <errno.h>
  #include <usb.h>
@@ -25,6 +27,8 @@ struct msm_ehci_priv {
        struct usb_ehci *ehci; /* Start of IP core*/
        struct ulpi_viewport ulpi_vp; /* ULPI Viewport */
        struct phy phy;
+       struct clk iface_clk;
+       struct clk core_clk;

You could simplify this with the bulk clock API, but I'm easy either way.

Reviewed-by: Caleb Connolly <caleb.conno...@linaro.org>

  };

static int msm_init_after_reset(struct ehci_ctrl *dev)

@@ -53,20 +57,46 @@ static int ehci_usb_probe(struct udevice *dev)
        struct ehci_hcor *hcor;
        int ret;

+ ret = clk_get_by_name(dev, "core", &p->core_clk);

+       if (ret) {
+               dev_err(dev, "Failed to get core clock: %d\n", ret);
+               return ret;
+       }
+
+       ret = clk_get_by_name(dev, "iface", &p->iface_clk);
+       if (ret) {
+               dev_err(dev, "Failed to get iface clock: %d\n", ret);
+               return ret;
+       }
+
+       ret = clk_prepare_enable(&p->core_clk);
+       if (ret)
+               return ret;
+
+       ret = clk_prepare_enable(&p->iface_clk);
+       if (ret)
+               goto cleanup_core;
+
        hccr = (struct ehci_hccr *)((phys_addr_t)&ehci->caplength);
        hcor = (struct ehci_hcor *)((phys_addr_t)hccr +
                        HC_LENGTH(ehci_readl(&(hccr)->cr_capbase)));

ret = generic_setup_phy(dev, &p->phy, 0);

        if (ret)
-               return ret;
+               goto cleanup_iface;

ret = board_usb_init(0, plat->init_type);

        if (ret < 0)
-               return ret;
+               goto cleanup_iface;

return ehci_register(dev, hccr, hcor, &msm_ehci_ops, 0,

                             plat->init_type);
+
+cleanup_iface:
+       clk_disable_unprepare(&p->iface_clk);
+cleanup_core:
+       clk_disable_unprepare(&p->core_clk);
+       return ret;
  }

static int ehci_usb_remove(struct udevice *dev)

@@ -82,6 +112,9 @@ static int ehci_usb_remove(struct udevice *dev)
        /* Stop controller. */
        clrbits_le32(&ehci->usbcmd, CMD_RUN);

+ clk_disable_unprepare(&p->iface_clk);

+       clk_disable_unprepare(&p->core_clk);
+
        ret = generic_shutdown_phy(&p->phy);
        if (ret)
                return ret;

--
// Caleb (they/them)