Re: [PATCH 4/4] usb: musb: Add support for MediaTek musb controller

From: Bin Liu
Date: Wed Jan 09 2019 - 09:02:06 EST


Hi Min,

On Wed, Jan 09, 2019 at 08:31:08PM +0800, Min Guo wrote:
> Hi Bin,
> On Tue, 2019-01-08 at 09:44 -0600, Bin Liu wrote:
> > Hi,
> >
> > On Thu, Dec 27, 2018 at 03:34:26PM +0800, min.guo@xxxxxxxxxxxx wrote:
> > > From: Min Guo <min.guo@xxxxxxxxxxxx>
> > >
> > > This adds support for MediaTek musb controller in
> > > host, peripheral and otg mode
> > >
> > > Signed-off-by: Min Guo <min.guo@xxxxxxxxxxxx>
> > > Signed-off-by: Yonglong Wu <yonglong.wu@xxxxxxxxxxxx>
> > > ---
> > > drivers/usb/musb/Kconfig | 8 +-
> > > drivers/usb/musb/Makefile | 1 +
> > > drivers/usb/musb/mediatek.c | 562 +++++++++++++++++++++++++++++++++++++++++++
> > > drivers/usb/musb/musb_core.c | 10 +
> > > drivers/usb/musb/musb_core.h | 1 +
> > > drivers/usb/musb/musb_dma.h | 1 +
> > > drivers/usb/musb/musb_host.c | 79 ++++--
> > > drivers/usb/musb/musb_regs.h | 6 +
> > > drivers/usb/musb/musbhsdma.c | 34 ++-
> > > 9 files changed, 671 insertions(+), 31 deletions(-)
> > > create mode 100644 drivers/usb/musb/mediatek.c
> > >
> > > diff --git a/drivers/usb/musb/Kconfig b/drivers/usb/musb/Kconfig
> > > index ad08895..540fc9f 100644
> > > --- a/drivers/usb/musb/Kconfig
> > > +++ b/drivers/usb/musb/Kconfig
> > > @@ -115,6 +115,12 @@ config USB_MUSB_JZ4740
> > > depends on USB_MUSB_GADGET
> > > depends on USB_OTG_BLACKLIST_HUB
> > >
> > > +config USB_MUSB_MEDIATEK
> > > + tristate "MediaTek platforms"
> > > + depends on ARCH_MEDIATEK
> >
> > Please also add '|| COMPILE_TEST' to make testing easier.
>
> Ok
>
> > > + depends on NOP_USB_XCEIV
> > > + depends on GENERIC_PHY
> > > +
> > > config USB_MUSB_AM335X_CHILD
> > > tristate
> > >
> > > @@ -141,7 +147,7 @@ config USB_UX500_DMA
> > >
> > > config USB_INVENTRA_DMA
> > > bool 'Inventra'
> > > - depends on USB_MUSB_OMAP2PLUS
> > > + depends on USB_MUSB_OMAP2PLUS || USB_MUSB_MEDIATEK
> > > help
> > > Enable DMA transfers using Mentor's engine.
> > >
> > > diff --git a/drivers/usb/musb/Makefile b/drivers/usb/musb/Makefile
> > > index 3a88c79..63d82d0 100644
> > > --- a/drivers/usb/musb/Makefile
> > > +++ b/drivers/usb/musb/Makefile
> > > @@ -24,6 +24,7 @@ obj-$(CONFIG_USB_MUSB_DA8XX) += da8xx.o
> > > obj-$(CONFIG_USB_MUSB_UX500) += ux500.o
> > > obj-$(CONFIG_USB_MUSB_JZ4740) += jz4740.o
> > > obj-$(CONFIG_USB_MUSB_SUNXI) += sunxi.o
> > > +obj-$(CONFIG_USB_MUSB_MEDIATEK) += mediatek.o
> > >
> > >
> > > obj-$(CONFIG_USB_MUSB_AM335X_CHILD) += musb_am335x.o
> > > diff --git a/drivers/usb/musb/mediatek.c b/drivers/usb/musb/mediatek.c
> > > new file mode 100644
> > > index 0000000..15a6460
> > > --- /dev/null
> > > +++ b/drivers/usb/musb/mediatek.c
> >
> > [snip]
> > I will review this section later after we sorted out other things.
> >
> > > diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
> > > index b7d5627..d60f76f 100644
> > > --- a/drivers/usb/musb/musb_core.c
> > > +++ b/drivers/usb/musb/musb_core.c
> > > @@ -1028,6 +1028,16 @@ static void musb_disable_interrupts(struct musb *musb)
> > > temp = musb_readb(mbase, MUSB_INTRUSB);
> > > temp = musb_readw(mbase, MUSB_INTRTX);
> > > temp = musb_readw(mbase, MUSB_INTRRX);
> > > +
> > > + /* MediaTek controller interrupt status is W1C */
> >
> > This W1C doesn't match to the MUSB Programming Guide that I have. Those
> > registers are read-only.
> > Is the difference due to the IP intergration in the mtk platforms? or is
> > it a new version of the MUSB controller? If latter, what is the version?
>
> This is difference due to the IP intergration in mtk platforms. W1C is
> easy for CpdeViser debug.
>
> > > + if (musb->ops->quirks & MUSB_MTK_QUIRKS) {
> >
> > Basically we don't want to use this type of platform specific quirks if
> > possible, so let's try to not use it.
>
> I will try my best to avoid using it.

Thanks.

>
> > > + musb_writeb(mbase, MUSB_INTRUSB,
> > > + musb_readb(mbase, MUSB_INTRUSB));
> >
> > For this clearing register bit operation, please create platform hooks
> > musb_clearb() and musb_clearw() in struct musb_platform_ops instead,
> > then follow how musb_readb() pointer is assigned in
> > musb_init_controller() to use the W1C version for mtk platform.
>
> I have tried implementing musb_readb(), musb_readw() interface with
> interrupt status W1C function in struct musb_platform_ops. But this
> interface will require a global variable to hold MAC basic address for
> judgment, and then special handling of the interrupt state. A global
> variable will make the driver work with only a single instance, so it
> can't work on some MTK platforms which have two instances.

I didn't mean to modify musb_read*(), but

> How about creating musb_clearb/w() as following:
> void (*clearb)(void __iomem *addr, unsigned offset, u8 data);
> void (*clearw)(void __iomem *addr, unsigned offset, u16 data);

this is what I was asking for, similar to what musb_readb/w() is
implemented.

>
>
> > > + musb_writew(mbase, MUSB_INTRRX,
> > > + musb_readw(mbase, MUSB_INTRRX));
> > > + musb_writew(mbase, MUSB_INTRTX,
> > > + musb_readw(mbase, MUSB_INTRTX));
> > > + }
> > > }
> > >
> > > static void musb_enable_interrupts(struct musb *musb)
> > > diff --git a/drivers/usb/musb/musb_core.h b/drivers/usb/musb/musb_core.h
> > > index 04203b7..1bf4e9a 100644
> > > --- a/drivers/usb/musb/musb_core.h
> > > +++ b/drivers/usb/musb/musb_core.h
> > > @@ -138,6 +138,7 @@ enum musb_g_ep0_state {
> > > */
> > > struct musb_platform_ops {
> > >
> > > +#define MUSB_MTK_QUIRKS BIT(10)
> > > #define MUSB_G_NO_SKB_RESERVE BIT(9)
> > > #define MUSB_DA8XX BIT(8)
> > > #define MUSB_PRESERVE_SESSION BIT(7)
> > > diff --git a/drivers/usb/musb/musb_dma.h b/drivers/usb/musb/musb_dma.h
> > > index 281e75d3..b218210 100644
> > > --- a/drivers/usb/musb/musb_dma.h
> > > +++ b/drivers/usb/musb/musb_dma.h
> > > @@ -197,6 +197,7 @@ static inline void musb_dma_controller_destroy(struct dma_controller *d) { }
> > > extern struct dma_controller *
> > > musbhs_dma_controller_create(struct musb *musb, void __iomem *base);
> > > extern void musbhs_dma_controller_destroy(struct dma_controller *c);
> > > +extern irqreturn_t dma_controller_irq(int irq, void *private_data);
> > >
> > > extern struct dma_controller *
> > > tusb_dma_controller_create(struct musb *musb, void __iomem *base);
> > > diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
> > > index b59ce9a..b1b0216 100644
> > > --- a/drivers/usb/musb/musb_host.c
> > > +++ b/drivers/usb/musb/musb_host.c
> > > @@ -292,20 +292,73 @@ static inline void musb_save_toggle(struct musb_qh *qh, int is_in,
> > > {
> > > void __iomem *epio = qh->hw_ep->regs;
> > > u16 csr;
> > > + struct musb *musb = qh->hw_ep->musb;
> > >
> > > /*
> > > * FIXME: the current Mentor DMA code seems to have
> > > * problems getting toggle correct.
> > > */
> > >
> > > - if (is_in)
> > > - csr = musb_readw(epio, MUSB_RXCSR) & MUSB_RXCSR_H_DATATOGGLE;
> > > - else
> > > - csr = musb_readw(epio, MUSB_TXCSR) & MUSB_TXCSR_H_DATATOGGLE;
> > > + /* MediaTek controller has private toggle register */
> >
> > only one toggle register for all endpoints? how does it handle
> > difference toggle values for different endpoints?
>
> MediaTek controller has separate registers to describe TX/RX toggle.

Is it one register per endpoint?

>
> > > + if (musb->ops->quirks & MUSB_MTK_QUIRKS) {
> > > + u16 toggle;
> > > + u8 epnum = qh->hw_ep->epnum;
> > > +
> > > + if (is_in)
> > > + toggle = musb_readl(musb->mregs, MUSB_RXTOG);

this line seems telling there is just *one* register for all endpoints.

> >
> > should use musb_readw() instead? MUSB_RXTOG seems to be 16bit.
>
> Ok
>
> > > + else
> > > + toggle = musb_readl(musb->mregs, MUSB_TXTOG);
> > > +
> > > + csr = toggle & (1 << epnum);
> > > + } else {
> > > + if (is_in)
> > > + csr = musb_readw(epio, MUSB_RXCSR)
> > > + & MUSB_RXCSR_H_DATATOGGLE;
> > > + else
> > > + csr = musb_readw(epio, MUSB_TXCSR)
> > > + & MUSB_TXCSR_H_DATATOGGLE;
> >
> > Does this logic still work for the mtk platform even if it has its own
> > private toggle register? If so, we don't need to change here.
>
> Sorry, this logic can not work on mtk platform, bit
> MUSB_RXCSR_H_DATATOGGLE and MUSB_TXCSR_H_DATATOGGLE are used for other
> function.

Is there a different controller RTL version we can use to
differentiate?

>
> > If not, let's try to not use this quirk flag. Please create a hook
> > musb_platform_get_toggle() in struct musb_platform_ops.
>
> Does the method of implement musb_platform_get_toggle() is prepare
> musb_default_get_toggle with common function, then follow how
> musb_readb() pointer is assigned in musb_init_controller()?

Yes, similar to musb_readb() implementation.

> How about creating musb_platform_get_toggle() as following:
> u16 (*get_toggle)(struct musb* musb, struct musb_qh *qh, int is_in);

yes, it is part of the implementation, then add it in struct musb_io.

>
> > > + }
> > >
> > > usb_settoggle(urb->dev, qh->epnum, !is_in, csr ? 1 : 0);
> > > }
> > >
> > > +static inline u16 musb_set_toggle(struct musb_qh *qh, int is_in,
> > > + struct urb *urb)
> > > +{
> > > + u16 csr = 0;
> > > + u16 toggle = 0;
> > > + struct musb *musb = qh->hw_ep->musb;
> > > + u8 epnum = qh->hw_ep->epnum;
> > > +
> > > + toggle = usb_gettoggle(urb->dev, qh->epnum, !is_in);
> > > +
> > > + /* MediaTek controller has private toggle register */
> > > + if (musb->ops->quirks & MUSB_MTK_QUIRKS) {
> > > + if (is_in) {
> > > + musb_writel(musb->mregs, MUSB_RXTOGEN, (1 << epnum));
> > > + musb_writel(musb->mregs, MUSB_RXTOG, (toggle << epnum));
> > > + } else {
> > > + musb_writel(musb->mregs, MUSB_TXTOGEN, (1 << epnum));
> > > + musb_writel(musb->mregs, MUSB_TXTOG, (toggle << epnum));
> > > + }
> > > + } else {
> > > + if (is_in) {
> > > + if (toggle)
> > > + csr = MUSB_RXCSR_H_WR_DATATOGGLE
> > > + | MUSB_RXCSR_H_DATATOGGLE;
> > > + else
> > > + csr = 0;
> > > + } else {
> > > + if (toggle)
> > > + csr |= MUSB_TXCSR_H_WR_DATATOGGLE
> > > + | MUSB_TXCSR_H_DATATOGGLE;
> > > + else
> > > + csr |= MUSB_TXCSR_CLRDATATOG;

'? :' operation probably is better than 'if else' here.

> > > + }
> > > + }
> > > + return csr;
> >
> > Please create a seperate patch for this musb_set_toggle() without adding
> > the mtk logic. It is a nice cleanup.
>
> Does this like get toggle implementation, create a hook
> musb_platform_set_toggle() in struct musb_platform_ops?

You did the code cleanup by creating musb_set_toggle(), please make it
in a separate patch, like

static u16 musb_set_toggle(struct musb_qh *qh, int is_in, struct urb *urb)
{
toggle = usb_gettoggle(urb->dev, qh->epnum, !is_in);
if (is_in)
csr = toggle ?
(MUSB_RXCSR_H_WR_DATATOGGLE | MUSB_RXCSR_H_DATATOGGLE) :
0;
else
csr = toggle ?
MUSB_TXCSR_H_WR_DATATOGGLE | MUSB_TXCSR_H_DATATOGGLE :
MUSB_TXCSR_CLRDATATOG;
return csr;
}

/* use musb_set_toggle() in the two instances */

then in this patch you add the mtk implementation similar as
*get_toggle() discussed above.

>
> > > +}
> > > +
> > > /*
> > > * Advance this hardware endpoint's queue, completing the specified URB and
> > > * advancing to either the next URB queued to that qh, or else invalidating
> > > @@ -772,13 +825,8 @@ static void musb_ep_program(struct musb *musb, u8 epnum,
> > > );
> > > csr |= MUSB_TXCSR_MODE;
> > >
> > > - if (!hw_ep->tx_double_buffered) {
> > > - if (usb_gettoggle(urb->dev, qh->epnum, 1))
> > > - csr |= MUSB_TXCSR_H_WR_DATATOGGLE
> > > - | MUSB_TXCSR_H_DATATOGGLE;
> > > - else
> > > - csr |= MUSB_TXCSR_CLRDATATOG;
> > > - }
> > > + if (!hw_ep->tx_double_buffered)
> > > + csr |= musb_set_toggle(qh, !is_out, urb);
> > >
> > > musb_writew(epio, MUSB_TXCSR, csr);
> > > /* REVISIT may need to clear FLUSHFIFO ... */
> > > @@ -860,17 +908,12 @@ static void musb_ep_program(struct musb *musb, u8 epnum,
> > >
> > > /* IN/receive */
> > > } else {
> > > - u16 csr;
> > > + u16 csr = 0;
> > >
> > > if (hw_ep->rx_reinit) {
> > > musb_rx_reinit(musb, qh, epnum);
> > > + csr |= musb_set_toggle(qh, !is_out, urb);
> > >
> > > - /* init new state: toggle and NYET, maybe DMA later */
> > > - if (usb_gettoggle(urb->dev, qh->epnum, 0))
> > > - csr = MUSB_RXCSR_H_WR_DATATOGGLE
> > > - | MUSB_RXCSR_H_DATATOGGLE;
> > > - else
> > > - csr = 0;
> > > if (qh->type == USB_ENDPOINT_XFER_INT)
> > > csr |= MUSB_RXCSR_DISNYET;
> > >
> > > diff --git a/drivers/usb/musb/musb_regs.h b/drivers/usb/musb/musb_regs.h
> > > index 5cd7264..ffbe267 100644
> > > --- a/drivers/usb/musb/musb_regs.h
> > > +++ b/drivers/usb/musb/musb_regs.h
> > > @@ -273,6 +273,12 @@
> > > #define MUSB_RXHUBADDR 0x06
> > > #define MUSB_RXHUBPORT 0x07
> > >
> > > +/* MediaTek controller toggle enable and status reg */
> > > +#define MUSB_RXTOG 0x80
> > > +#define MUSB_RXTOGEN 0x82
> > > +#define MUSB_TXTOG 0x84
> > > +#define MUSB_TXTOGEN 0x86
> >
> > Again, these offsets are for different registers in the MUSB version I
> > have, please let me know if you have different version of the MUSB IP.
>
> Sorry, these are MediaTek controller private registers used for control
> toggle.

Okay. Once the platform get/set_toggle() are implemented, those
registers can be defined in the mtk glue driver instead of here.

Regards,
-Bin.