On 2/29/2024 3:17 PM, Johan Hovold wrote:
On Fri, Feb 16, 2024 at 06:27:49AM +0530, Krishna Kurapati wrote:
Currently Multiport DWC3 controllers are host-only capable.
I already asked you to rephrase this so that it becomes clear that you
are describing a property of the current hardware (and similar
throughout the series):
https://lore.kernel.org/all/ZTI7AtCJWgAnACSh@xxxxxxxxxxxxxxxxxxxx/
Hi Johan. Thanks for the review.
IMO, the statement is describing a property unique to current hardware,
that "If it is a multiport controller, it is then host-only capable"
I used the word "Currently" to indicate that "Today, the multiport
devices present...". Let me know if there is any ambiguity in the sentence.
In v13, I wrote:
"Currently host-only capable DWC3 controllers support Multiport."
You were right. It was ambiguous as it might refer to even single port
controllers.
So I changed it saying all the DWC3 multiport controllers are host only
capable.
How about:
"All the DWC3 Multi Port controllers that exist today only support host
mode"
+static int dwc3_read_port_info(struct dwc3 *dwc)
+{
+ void __iomem *base;
+ u8 major_revision;
+ u32 offset;
+ u32 val;
+
+ /*
+ * Remap xHCI address space to access XHCI ext cap regs since it is
+ * needed to get information on number of ports present.
+ */
+ base = ioremap(dwc->xhci_resources[0].start,
+ resource_size(&dwc->xhci_resources[0]));
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ offset = 0;
+ do {
+ offset = xhci_find_next_ext_cap(base, offset,
+ XHCI_EXT_CAPS_PROTOCOL);
+ if (!offset)
+ break;
+
+ val = readl(base + offset);
+ major_revision = XHCI_EXT_PORT_MAJOR(val);
+
+ val = readl(base + offset + 0x08);
+ if (major_revision == 0x03) {
+ dwc->num_usb3_ports += XHCI_EXT_PORT_COUNT(val);
+ } else if (major_revision <= 0x02) {
+ dwc->num_usb2_ports += XHCI_EXT_PORT_COUNT(val);
+ } else {
+ dev_warn(dwc->dev,
+ "unrecognized port major revision %d\n",
I still think you should merge this with the previous line even if you
end up with 83 chars.
+ major_revision);
+ }
+ } while (1);
+ /*
+ * Currently only DWC3 controllers that are host-only capable
+ * support Multiport.
+ */
So again, also here, rephrase the comment so that it is clear that you
are referring to a property of the current hardware.
I put the comment this way to indicate that we don't want to check for
existence of multiple ports if the controller is not "host-only"
capable. We should only check for multport support only if we are
host-only capable. I think the statement clearly tells that "check for
host-only" configuration before proceeding to check for xhci register reads.
I replied the same on:
https://lore.kernel.org/all/279a54f2-7260-4270-83c7-d6f5c5ba0873@xxxxxxxxxxx/
And since you didn't mention anything else at this part of code in your
return reply in:
https://lore.kernel.org/all/ZTYyXhyZN3jBXEfm@xxxxxxxxxxxxxxxxxxxx/
I thought this statement was fine to go.
+ hw_mode = DWC3_GHWPARAMS0_MODE(dwc->hwparams.hwparams0);
+ if (hw_mode == DWC3_GHWPARAMS0_MODE_HOST) {
+ ret = dwc3_read_port_info(dwc);
+ if (ret)
+ goto err_disable_clks;
+ } else {
+ dwc->num_usb2_ports = 1;
+ dwc->num_usb3_ports = 1;
+ }
Thanks for the review. Can you help let me know your review on the other
patches as well.
Regards,
Krishna,
