Re: [PATCH v2 1/3] usb: orion-echi: Add support for the Armada 3700
From: Gregory CLEMENT
Date: Thu Mar 09 2017 - 10:23:20 EST
On jeu., mars 09 2017, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
>> @@ -47,6 +47,21 @@
>> #define USB_PHY_IVREF_CTRL 0x440
>> #define USB_PHY_TST_GRP_CTRL 0x450
>> +#define USB_SBUSCFG 0x90
>> +#define USB_SBUSCFG_BAWR_SHIFT 0x6
>> +#define USB_SBUSCFG_BARD_SHIFT 0x3
>> +#define USB_SBUSCFG_AHBBRST_SHIFT 0x0
> Shift amounts are just regular numbers. Giving them in hex is
> confusing because it leads people to think the bit pattern has some
> particular significance, which it doesn't. Which would you rather see:
> (0x24 << 0x12) or (0x24 << 18)?
>> +/* BAWR = BARD = 3 : Align read/write bursts packets larger than 128 bytes */
>> +#define USB_SBUSCFG_BAWR_ALIGN_128B (0x3 << USB_SBUSCFG_BAWR_SHIFT)
>> +#define USB_SBUSCFG_BARD_ALIGN_128B (0x3 << USB_SBUSCFG_BARD_SHIFT)
>> +/* AHBBRST = 3 : Align AHB Burst to INCR16 (64 bytes) */
>> +#define USB_SBUSCFG_AHBBRST_INCR16 (0x3 << USB_SBUSCFG_AHBBRST_SHIFT)
> Besides, since these shift amounts are each used only once, it would be
> simpler (and easier to read!) to do:
> +#define USB_SBUSCFG_BAWR_ALIGN_128B (0x3 << 6)
> +#define USB_SBUSCFG_BARD_ALIGN_128B (0x3 << 3)
> +/* AHBBRST = 3 : Align AHB Burst to INCR16 (64 bytes) */
> +#define USB_SBUSCFG_AHBBRST_INCR16 (0x3 << 0)
I think the intent was to document the register layout. But I have no
problem following your advice.
>> +#define USB_SBUSCFG_DEF_VAL (USB_SBUSCFG_BAWR_ALIGN_128B \
>> + | USB_SBUSCFG_BARD_ALIGN_128B \
>> + | USB_SBUSCFG_AHBBRST_INCR16)
>> #define DRIVER_DESC "EHCI orion driver"
>> #define hcd_to_orion_priv(h) ((struct orion_ehci_hcd *)hcd_to_ehci(h)->priv)
>> @@ -151,8 +166,31 @@ ehci_orion_conf_mbus_windows(struct usb_hcd *hcd,
>> +static int ehci_orion_drv_reset(struct usb_hcd *hcd)
>> + struct device *dev = hcd->self.controller;
>> + int retval;
>> + retval = ehci_setup(hcd);
>> + if (retval)
>> + dev_err(dev, "ehci_setup failed %d\n", retval);
> Was lack of this error message in the original driver a source of
> problems? If not, I submit that there's no good reason to add it.
I will remove the message and replace it by "return retval;" as
>> + /*
>> + * For SoC without hlock, need to program sbuscfg value to guarantee
>> + * AHB master's burst would not overrun or underrun FIFO.
>> + *
>> + * sbuscfg reg has to be set after usb controller reset, otherwise
>> + * the value would be override to 0.
>> + */
>> + if (of_device_is_compatible(dev->of_node, "marvell,armada-3700-ehci"))
>> + wrl(USB_SBUSCFG, USB_SBUSCFG_DEF_VAL);
> Do you want to do this even when retval != 0?
> Alan Stern
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.