From: Jung Daehwan <dh10.jung@samsung.com>
To: Mathias Nyman <mathias.nyman@linux.intel.com>
Cc: Mathias Nyman <mathias.nyman@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"open list:USB XHCI DRIVER" <linux-usb@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
Howard Yen <howardyen@google.com>,
Jack Pham <jackp@codeaurora.org>, Puma Hsu <pumahsu@google.com>,
"J . Avila" <elavila@google.com>,
sc.suh@samsung.com,
Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Subject: Re: [PATCH v4 5/5] usb: host: add xhci-exynos driver
Date: Thu, 28 Apr 2022 14:15:22 +0900 [thread overview]
Message-ID: <20220428051522.GE151827@ubuntu> (raw)
In-Reply-To: <b9fcc518-cc0d-d346-774e-3a9472e664bc@linux.intel.com>
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On Wed, Apr 27, 2022 at 07:25:21PM +0300, Mathias Nyman wrote:
> On 26.4.2022 12.18, Daehwan Jung wrote:
> > This driver is for Samsung Exynos xhci host conroller. It uses xhci-plat
> > driver mainly and extends some functions by xhci hooks and overrides.
> >
> > It supports USB Audio offload with Co-processor. It only cares DCBAA,
> > Device Context, Transfer Ring, Event Ring, and ERST. They are allocated
> > on specific address with xhci hooks. Co-processor could use them directly
> > without xhci driver after then.
> >
> > Signed-off-by: Daehwan Jung <dh10.jung@samsung.com>
>
> I have to agree with Krzysztof's comments, this is an odd driver stub.
>
> Perhaps open up a bit how the Exynos offloading works so we can figure out
> in more detail what the hardware needs from software.
>
> (...)
>
I missed replying here on previous one.
OK. It seems to need more detailed explanation. I will explain my driver
more detail on next submission.
> > +
> > +static void xhci_exynos_alloc_container_ctx(struct xhci_hcd *xhci, struct xhci_container_ctx *ctx,
> > + int type, gfp_t flags)
> > +{
> > + /* Only first Device Context uses URAM */
> > + int i;
> > +
> > + ctx->bytes = ioremap(EXYNOS_URAM_DEVICE_CTX_ADDR, EXYNOS_URAM_CTX_SIZE);
> > + if (!ctx->bytes)
> > + return;
> > +
> > + for (i = 0; i < EXYNOS_URAM_CTX_SIZE; i++)
> > + ctx->bytes[i] = 0;
> > +
> > + ctx->dma = EXYNOS_URAM_DEVICE_CTX_ADDR;
>
> This can't work with more than one USB device.
> This hardcodes the same context address for every usb device.
>
>
> > +static void xhci_exynos_parse_endpoint(struct xhci_hcd *xhci, struct usb_device *udev,
> > + struct usb_endpoint_descriptor *desc, struct xhci_container_ctx *ctx)
> > +{
> > + struct xhci_plat_priv *priv = xhci_to_priv(xhci);
> > + struct xhci_hcd_exynos *xhci_exynos = priv->vendor_priv;
> > + struct usb_endpoint_descriptor *d = desc;
> > + unsigned int ep_index;
> > + struct xhci_ep_ctx *ep_ctx;
> > +
> > + ep_index = xhci_get_endpoint_index(d);
> > + ep_ctx = xhci_get_ep_ctx(xhci, ctx, ep_index);
> > +
> > + if ((d->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
> > + USB_ENDPOINT_XFER_ISOC) {
> > + if (d->bEndpointAddress & USB_ENDPOINT_DIR_MASK)
> > + xhci_exynos->in_ep = d->bEndpointAddress;
> > + else
> > + xhci_exynos->out_ep = d->bEndpointAddress;
> > + }
>
> This won't work if more than one device that has isoc endpoints, or even
> if that device has more than one in/out isoc endpoint pair.
>
>
I missed it also on previous mail.
I've never seen a device that has several isoc endpoints.
It needs to add something if it would exist.
In fact, I've found a device that has feedback ep and I'm going to add
it. I've never seen other case yet.
Best Regards,
Jung Daehwan
> > +static int xhci_alloc_segments_for_ring_uram(struct xhci_hcd *xhci,
> > + struct xhci_segment **first, struct xhci_segment **last,
> > + unsigned int num_segs, unsigned int cycle_state,
> > + enum xhci_ring_type type, unsigned int max_packet, gfp_t flags,
> > + u32 endpoint_type)
> > +{
> > + struct xhci_segment *prev;
> > + bool chain_links = false;
> > +
> > + while (num_segs > 0) {
> > + struct xhci_segment *next = NULL;
> > +
> > + if (!next) {
> > + prev = *first;
> > + while (prev) {
> > + next = prev->next;
> > + xhci_segment_free(xhci, prev);
> > + prev = next;
> > + }
> > + return -ENOMEM;
>
> This always return -ENOMEM
>
> Also this whole function never allocates or remaps any memory.
>
> > + }
> > + xhci_link_segments(prev, next, type, chain_links);
> > +
> > + prev = next;
> > + num_segs--;
> > + }
> > + xhci_link_segments(prev, *first, type, chain_links);
> > + *last = prev;
> > +
> > + return 0;
> > +}
> > +
> > +static struct xhci_ring *xhci_ring_alloc_uram(struct xhci_hcd *xhci,
> > + unsigned int num_segs, unsigned int cycle_state,
> > + enum xhci_ring_type type, unsigned int max_packet, gfp_t flags,
> > + u32 endpoint_type)
> > +{
> > + struct xhci_ring *ring;
> > + int ret;
> > + struct device *dev = xhci_to_hcd(xhci)->self.sysdev;
> > +
> > + ring = kzalloc_node(sizeof(*ring), flags, dev_to_node(dev));
> > + if (!ring)
> > + return NULL;
> > +
> > + ring->num_segs = num_segs;
> > + ring->bounce_buf_len = max_packet;
> > + INIT_LIST_HEAD(&ring->td_list);
> > + ring->type = type;
> > + if (num_segs == 0)
> > + return ring;
> > +
> > + ret = xhci_alloc_segments_for_ring_uram(xhci, &ring->first_seg,
> > + &ring->last_seg, num_segs, cycle_state, type,
> > + max_packet, flags, endpoint_type);
> > + if (ret)
> > + goto fail;
> > +
> > + /* Only event ring does not use link TRB */
> > + if (type != TYPE_EVENT) {
> > + /* See section 4.9.2.1 and 6.4.4.1 */
> > + ring->last_seg->trbs[TRBS_PER_SEGMENT - 1].link.control |=
> > + cpu_to_le32(LINK_TOGGLE);
>
> No memory was allocated for trbs
>
> A lot of this code seems to exists just to avoid xhci driver from allocating
> dma capable memory, we can refactor the existing xhci_mem_init() and move
> dcbaa and event ring allocation and other code to their own overridable
> functions.
>
> This way we can probably get rid of a lot of the code in this series.
>
> Thanks
> Mathias
>
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next prev parent reply other threads:[~2022-04-28 5:17 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20220426092019epcas2p2ef5dfde273edaaadc2ff74414f1b2c7a@epcas2p2.samsung.com>
2022-04-26 9:18 ` [PATCH v4 0/5] add xhci-exynos driver Daehwan Jung
[not found] ` <CGME20220426092021epcas2p4071f2b7621558a015579131990486a3c@epcas2p4.samsung.com>
2022-04-26 9:18 ` [PATCH v4 1/5] usb: host: export symbols for xhci-exynos to use xhci hooks Daehwan Jung
2022-04-26 9:54 ` Greg Kroah-Hartman
2022-04-26 10:27 ` Jung Daehwan
2022-04-26 10:31 ` Greg Kroah-Hartman
2022-04-26 18:40 ` Greg Kroah-Hartman
2022-04-28 3:30 ` Jung Daehwan
2022-04-26 16:02 ` kernel test robot
[not found] ` <CGME20220426092021epcas2p1a8d41039d9b3226f4e00f7d4bded833a@epcas2p1.samsung.com>
2022-04-26 9:18 ` [PATCH v4 2/5] usb: host: add xhci hooks for xhci-exynos Daehwan Jung
2022-04-26 10:19 ` Greg Kroah-Hartman
2022-04-27 9:06 ` Jung Daehwan
2022-04-27 9:19 ` Greg Kroah-Hartman
2022-04-28 3:23 ` Jung Daehwan
2022-04-28 5:30 ` Greg Kroah-Hartman
[not found] ` <CGME20220426092022epcas2p2da47c0c20feba6c96037e125289475f9@epcas2p2.samsung.com>
2022-04-26 9:18 ` [PATCH v4 3/5] usb: host: xhci-plat: support override of hc driver Daehwan Jung
2022-04-26 10:20 ` Greg Kroah-Hartman
2022-04-27 9:07 ` Jung Daehwan
[not found] ` <CGME20220426092022epcas2p2c016c83b21e41c7bcd4bdfbb95e464c0@epcas2p2.samsung.com>
2022-04-26 9:18 ` [PATCH v4 4/5] usb: host: add some to xhci overrides for xhci-exynos Daehwan Jung
2022-04-26 10:23 ` Greg Kroah-Hartman
2022-04-27 9:19 ` Jung Daehwan
2022-04-27 9:37 ` Greg Kroah-Hartman
[not found] ` <CGME20220426092023epcas2p32946c087135ca4b7e63b03915060c55d@epcas2p3.samsung.com>
2022-04-26 9:18 ` [PATCH v4 5/5] usb: host: add xhci-exynos driver Daehwan Jung
2022-04-26 10:20 ` Greg Kroah-Hartman
2022-04-28 3:26 ` Jung Daehwan
2022-04-26 10:21 ` Greg Kroah-Hartman
2022-04-27 9:24 ` Jung Daehwan
2022-04-27 9:37 ` Greg Kroah-Hartman
2022-04-26 12:59 ` Krzysztof Kozlowski
2022-04-28 1:29 ` Jung Daehwan
2022-04-28 5:19 ` Krzysztof Kozlowski
2022-04-28 6:36 ` Jung Daehwan
2022-04-28 6:45 ` Greg Kroah-Hartman
2022-04-28 7:45 ` Jung Daehwan
2022-04-28 7:31 ` Krzysztof Kozlowski
2022-04-28 7:53 ` Jung Daehwan
2022-04-28 8:26 ` Krzysztof Kozlowski
2022-04-26 17:55 ` kernel test robot
2022-04-27 16:25 ` Mathias Nyman
2022-04-28 3:03 ` Jung Daehwan
2022-04-28 12:28 ` Mathias Nyman
2022-05-03 8:41 ` Jung Daehwan
2022-04-28 5:15 ` Jung Daehwan [this message]
2022-04-26 10:19 ` [PATCH v4 0/5] " Greg Kroah-Hartman
2022-04-26 12:46 ` Krzysztof Kozlowski
2022-04-27 9:49 ` Jung Daehwan
2022-04-27 18:24 ` Krzysztof Kozlowski
2022-04-28 3:19 ` Jung Daehwan
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