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Date:   Mon, 9 May 2022 11:16:31 +0800
From:   Peter Chen <peter.chen@kernel.org>
To:     Zhi Li <lznuaa@gmail.com>
Cc:     Frank Li <Frank.Li@nxp.com>, pawell@cadence.com, rogerq@kernel.org,
        a-govindraju@ti.com, linux-usb@vger.kernel.org,
        Jun Li <jun.li@nxp.com>, Greg KH <gregkh@linuxfoundation.org>,
        kernel list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v8 1/1] usb: cdns3: allocate TX FIFO size according to
 composite EP number
Message-ID: <20220509031631.GA499681@Peter>
References: <20220427163525.1129887-1-Frank.Li@nxp.com>
 <20220505022111.GA433739@Peter>
 <CAHrpEqTK9pa07RvnL7BWZfprrk5Rsg3qR0N5XgKcUiQqHsYwcA@mail.gmail.com>
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On 22-05-05 10:24:12, Zhi Li wrote:
> On Wed, May 4, 2022 at 9:21 PM Peter Chen <peter.chen@kernel.org> wrote:
> >
> > On 22-04-27 11:35:25, Frank Li wrote:
> > > Some devices have USB compositions which may require multiple endpoints.
> > > To get better performance, need bigger CDNS3_EP_BUF_SIZE.
> > >
> > > But bigger CDNS3_EP_BUF_SIZE may exceed total hardware FIFO size when
> > > multiple endpoints.
> > >
> > > By introducing the check_config() callback, calculate CDNS3_EP_BUF_SIZE.
> > >
> > > Move CDNS3_EP_BUF_SIZE into cnds3_device: ep_buf_size
> > > Combine CDNS3_EP_ISO_SS_BURST and CDNS3_EP_ISO_HS_MULT into
> > > ecnds3_device:ep_iso_burst
> >
> > typo, and would you please explain usage for ep_iso_burst in your patch?
> 
> ep_iso_burst just directly replaced old CDNS3_EP_ISO_SS_BURST.
> 
> This patch uses a simple algorithm to make ep_buf_size equal to ep_iso_burst.
> 
> using ep_iso_burst reduces code change and keeps old code logic.
> Keep capability to finial tune ep_iso_burst for ep_buf_size in future
> for difference
> composite devices combination user case.
> 
> >
> > >
> > > Using a simple algorithm to calculate ep_buf_size.
> > > ep_buf_size = ep_iso_burst = (onchip_buffers - 2k) / (number of IN EP +
> > > 1).
> > >
> > > Test at 8qxp:
> > >
> > >       Gadget                  ep_buf_size
> > >
> > >       RNDIS:                          5
> > >       RNDIS+ACM:                      3
> > >       Mass Storage + NCM + ACM        2
> > >
> > > Previous CDNS3_EP_BUF_SIZE is 4, RNDIS + ACM will be failure because
> > > exceed FIFO memory.
> > >
> > > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> > > ---
> > > Change from v1 to v2:
> > >  Add safe check for mult, buffering and maxburst
> > >
> > >  drivers/usb/cdns3/cdns3-gadget.c | 50 +++++++++++++++++++++++++++++---
> > >  drivers/usb/cdns3/cdns3-gadget.h |  9 ++++--
> > >  2 files changed, 52 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
> > > index 1f3b4a1422126..e25e7a2b55862 100644
> > > --- a/drivers/usb/cdns3/cdns3-gadget.c
> > > +++ b/drivers/usb/cdns3/cdns3-gadget.c
> > > @@ -2050,7 +2050,7 @@ int cdns3_ep_config(struct cdns3_endpoint *priv_ep, bool enable)
> > >       u8 mult = 0;
> > >       int ret;
> > >
> > > -     buffering = CDNS3_EP_BUF_SIZE - 1;
> > > +     buffering = priv_dev->ep_buf_size - 1;
> > >
> > >       cdns3_configure_dmult(priv_dev, priv_ep);
> > >
> > > @@ -2069,7 +2069,7 @@ int cdns3_ep_config(struct cdns3_endpoint *priv_ep, bool enable)
> > >               break;
> > >       default:
> > >               ep_cfg = EP_CFG_EPTYPE(USB_ENDPOINT_XFER_ISOC);
> > > -             mult = CDNS3_EP_ISO_HS_MULT - 1;
> > > +             mult = priv_dev->ep_iso_burst - 1;
> > >               buffering = mult + 1;
> > >       }
> > >
> > > @@ -2085,14 +2085,14 @@ int cdns3_ep_config(struct cdns3_endpoint *priv_ep, bool enable)
> > >               mult = 0;
> > >               max_packet_size = 1024;
> > >               if (priv_ep->type == USB_ENDPOINT_XFER_ISOC) {
> > > -                     maxburst = CDNS3_EP_ISO_SS_BURST - 1;
> > > +                     maxburst = priv_dev->ep_iso_burst - 1;
> > >                       buffering = (mult + 1) *
> > >                                   (maxburst + 1);
> > >
> > >                       if (priv_ep->interval > 1)
> > >                               buffering++;
> > >               } else {
> > > -                     maxburst = CDNS3_EP_BUF_SIZE - 1;
> > > +                     maxburst = priv_dev->ep_buf_size - 1;
> > >               }
> > >               break;
> > >       default:
> > > @@ -2136,6 +2136,10 @@ int cdns3_ep_config(struct cdns3_endpoint *priv_ep, bool enable)
> > >               ep_cfg |=  EP_CFG_STREAM_EN | EP_CFG_TDL_CHK | EP_CFG_SID_CHK;
> > >       }
> > >
> > > +     mult = min_t(u8, mult, EP_CFG_MULT_MAX);
> > > +     buffering = min_t(u8, buffering, EP_CFG_BUFFERING_MAX);
> > > +     maxburst = min_t(u8, maxburst, EP_CFG_MAXBURST_MAX);

These compare need to move above to keep variable "buffering" calculation
correctly.

> > > +
> > >       ep_cfg |= EP_CFG_MAXPKTSIZE(max_packet_size) |
> > >                 EP_CFG_MULT(mult) |
> > >                 EP_CFG_BUFFERING(buffering) |
> > > @@ -2970,6 +2974,43 @@ static int cdns3_gadget_udc_stop(struct usb_gadget *gadget)
> > >       return 0;
> > >  }
> > >
> > > +/**
> > > + * cdns3_gadget_check_config - ensure cdns3 can support the USB configuration
> > > + * @gadget: pointer to the USB gadget
> > > + *
> > > + * Used to record the maximum number of endpoints being used in a USB composite
> > > + * device. (across all configurations)  This is to be used in the calculation
> > > + * of the TXFIFO sizes when resizing internal memory for individual endpoints.
> > > + * It will help ensured that the resizing logic reserves enough space for at
> > > + * least one max packet.
> > > + */
> > > +static int cdns3_gadget_check_config(struct usb_gadget *gadget)
> > > +{
> > > +     struct cdns3_device *priv_dev = gadget_to_cdns3_device(gadget);
> > > +     struct usb_ep *ep;
> > > +     int n_in = 0;
> > > +     int total;
> > > +
> > > +     list_for_each_entry(ep, &gadget->ep_list, ep_list) {
> > > +             if (ep->claimed && (ep->address & USB_DIR_IN))
> > > +                     n_in++;
> > > +     }
> > > +
> > > +     priv_dev->ep_buf_size = 1;
> > > +     priv_dev->ep_iso_burst = 1;
> >
> > You will re-calculate above variables below, why need to initialize them?
> 
> I worry about it is 0 or other random data at below error return branch.
> Anyway, it should be okay to remove it.

If it is failed, the .bind will fail, so it is okay to remove these.

Other parts are okay for me.

Peter

> 
> >
> > Peter
> > > +
> > > +     /* 2KB are reserved for EP0, 1KB for out*/
> > > +     total = 2 + n_in + 1;
> > > +
> > > +     if (total > priv_dev->onchip_buffers)
> > > +             return -ENOMEM;
> > > +
> > > +     priv_dev->ep_buf_size = priv_dev->ep_iso_burst =
> > > +                     (priv_dev->onchip_buffers - 2) / (n_in + 1);
> > > +
> > > +     return 0;
> > > +}
> > > +
> > >  static const struct usb_gadget_ops cdns3_gadget_ops = {
> > >       .get_frame = cdns3_gadget_get_frame,
> > >       .wakeup = cdns3_gadget_wakeup,
> > > @@ -2978,6 +3019,7 @@ static const struct usb_gadget_ops cdns3_gadget_ops = {
> > >       .udc_start = cdns3_gadget_udc_start,
> > >       .udc_stop = cdns3_gadget_udc_stop,
> > >       .match_ep = cdns3_gadget_match_ep,
> > > +     .check_config = cdns3_gadget_check_config,
> > >  };
> > >
> > >  static void cdns3_free_all_eps(struct cdns3_device *priv_dev)
> > > diff --git a/drivers/usb/cdns3/cdns3-gadget.h b/drivers/usb/cdns3/cdns3-gadget.h
> > > index c5660f2c4293f..fbe4a8e3aa897 100644
> > > --- a/drivers/usb/cdns3/cdns3-gadget.h
> > > +++ b/drivers/usb/cdns3/cdns3-gadget.h
> > > @@ -562,15 +562,18 @@ struct cdns3_usb_regs {
> > >  /* Max burst size (used only in SS mode). */
> > >  #define EP_CFG_MAXBURST_MASK GENMASK(11, 8)
> > >  #define EP_CFG_MAXBURST(p)   (((p) << 8) & EP_CFG_MAXBURST_MASK)
> > > +#define EP_CFG_MAXBURST_MAX  15
> > >  /* ISO max burst. */
> > >  #define EP_CFG_MULT_MASK     GENMASK(15, 14)
> > >  #define EP_CFG_MULT(p)               (((p) << 14) & EP_CFG_MULT_MASK)
> > > +#define EP_CFG_MULT_MAX              2
> > >  /* ISO max burst. */
> > >  #define EP_CFG_MAXPKTSIZE_MASK       GENMASK(26, 16)
> > >  #define EP_CFG_MAXPKTSIZE(p) (((p) << 16) & EP_CFG_MAXPKTSIZE_MASK)
> > >  /* Max number of buffered packets. */
> > >  #define EP_CFG_BUFFERING_MASK        GENMASK(31, 27)
> > >  #define EP_CFG_BUFFERING(p)  (((p) << 27) & EP_CFG_BUFFERING_MASK)
> > > +#define EP_CFG_BUFFERING_MAX 15
> > >
> > >  /* EP_CMD - bitmasks */
> > >  /* Endpoint reset. */
> > > @@ -1094,9 +1097,6 @@ struct cdns3_trb {
> > >  #define CDNS3_ENDPOINTS_MAX_COUNT    32
> > >  #define CDNS3_EP_ZLP_BUF_SIZE                1024
> > >
> > > -#define CDNS3_EP_BUF_SIZE            4       /* KB */
> > > -#define CDNS3_EP_ISO_HS_MULT         3
> > > -#define CDNS3_EP_ISO_SS_BURST                3
> > >  #define CDNS3_MAX_NUM_DESCMISS_BUF   32
> > >  #define CDNS3_DESCMIS_BUF_SIZE               2048    /* Bytes */
> > >  #define CDNS3_WA2_NUM_BUFFERS                128
> > > @@ -1333,6 +1333,9 @@ struct cdns3_device {
> > >       /*in KB */
> > >       u16                             onchip_buffers;
> > >       u16                             onchip_used_size;
> > > +
> > > +     u16                             ep_buf_size;
> > > +     u16                             ep_iso_burst;
> > >  };
> > >
> > >  void cdns3_set_register_bit(void __iomem *ptr, u32 mask);
> > > --
> > > 2.35.1
> > >
> >
> > --
> >
> > Thanks,
> > Peter Chen
> >

-- 

Thanks,
Peter Chen