Re: [PATCH v8 5/9] usb: dwc3: core: Refactor PHY logic to support Multiport Controller

Bjorn Andersson
2023-05-15T21:43:57Z

On Sun, May 14, 2023 at 11:19:13AM +0530, Krishna Kurapati wrote:
> Currently the DWC3 driver supports only single port controller
> which requires at most one HS and one SS PHY.
>
> But the DWC3 USB controller can be connected to multiple ports and
> each port can have their own PHYs. Each port of the multiport
> controller can either be HS+SS capable or HS only capable
> Proper quantification of them is required to modify GUSB2PHYCFG
> and GUSB3PIPECTL registers appropriately.
>
> Add support for detecting, obtaining and configuring phy's supported
> by a multiport controller and limit the max number of ports
> supported to 4.
>
> Co-developed-by: Harsh Agarwal <quic_harshq@quicinc.com>

Please include Harsh's signed-off-by as well here, to clarify that you
both certify the origin of this patch.

> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> ---
> drivers/usb/dwc3/core.c | 266 ++++++++++++++++++++++++++++++----------
> drivers/usb/dwc3/core.h | 11 +-
> drivers/usb/dwc3/drd.c | 13 +-
> 3 files changed, 213 insertions(+), 77 deletions(-)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
[..]
> @@ -744,22 +777,38 @@ static int dwc3_phy_setup(struct dwc3 *dwc)
> static int dwc3_phy_init(struct dwc3 *dwc)
> {
> int ret;
> + int i;
> + int j;
>
> usb_phy_init(dwc->usb2_phy);
> usb_phy_init(dwc->usb3_phy);
>
> - ret = phy_init(dwc->usb2_generic_phy);
> - if (ret < 0)
> - goto err_shutdown_usb3_phy;
> + for (i = 0; i < dwc->num_usb2_ports; i++) {
> + ret = phy_init(dwc->usb2_generic_phy[i]);
> + if (ret < 0) {
> + /* clean up prior initialized HS PHYs */
> + for (j = 0; j < i; j++)
> + phy_exit(dwc->usb2_generic_phy[j]);
> + goto err_shutdown_usb3_phy;

The idiomatic form is to goto err_exit_usb2_phy and let it phy_exit()
from i - 1 to 0. That would avoid duplicating this snippet.

> + }
> + }
>
> - ret = phy_init(dwc->usb3_generic_phy);
> - if (ret < 0)
> - goto err_exit_usb2_phy;
> + for (i = 0; i < dwc->num_usb2_ports; i++) {

When you call dwc3_ss_phy_setup() the index refer to port0, port1... but
when you refer to the phys you consistently loops over num_usb2_ports.

The only case I can think of where this would be useful is if it's not
the first N ports that are SS-capable (e.g. port0 and port can do SS).

If this is the case, is it correct that this should not be reflected in
the index passed to e.g. dwc3_ss_phy_setup()?

If this is not the case, could you please transition these SS-related
loops to iterate over usb3_generic_phy[0..num_usb3_ports)?

> + ret = phy_init(dwc->usb3_generic_phy[i]);
> + if (ret < 0) {
> + /* clean up prior initialized SS PHYs */
> + for (j = 0; j < i; j++)
> + phy_exit(dwc->usb3_generic_phy[j]);
> + goto err_exit_usb2_phy;

For the purpose of symmetry, same suggestion as above. phy_exit() i - 1
through 0, then reset j to dwc->num_usb2_ports and fall through to
err_exit_usb2_phy.

> + }
> + }
>
> return 0;
>
> err_exit_usb2_phy:
> - phy_exit(dwc->usb2_generic_phy);
> + for (i = 0; i < dwc->num_usb2_ports; i++)
> + phy_exit(dwc->usb2_generic_phy[i]);
> +
> err_shutdown_usb3_phy:
> usb_phy_shutdown(dwc->usb3_phy);
> usb_phy_shutdown(dwc->usb2_phy);
> @@ -769,8 +818,12 @@ static int dwc3_phy_init(struct dwc3 *dwc)
[..]
> static int dwc3_phy_power_on(struct dwc3 *dwc)
> {
> int ret;
> + int i;
> + int j;
>
> usb_phy_set_suspend(dwc->usb2_phy, 0);
> usb_phy_set_suspend(dwc->usb3_phy, 0);
>
> - ret = phy_power_on(dwc->usb2_generic_phy);
> - if (ret < 0)
> - goto err_suspend_usb3_phy;
> + for (i = 0; i < dwc->num_usb2_ports; i++) {
> + ret = phy_power_on(dwc->usb2_generic_phy[i]);
> + if (ret < 0) {
> + /* Turn off prior ON'ed HS Phy's */
> + for (j = 0; j < i; j++)
> + phy_power_off(dwc->usb2_generic_phy[j]);
> + goto err_suspend_usb3_phy;

As above, I'd prefer that you don't duplicate the phy_power_off() loop.

> + }
> + }
>
> - ret = phy_power_on(dwc->usb3_generic_phy);
> - if (ret < 0)
> - goto err_power_off_usb2_phy;
> + for (i = 0; i < dwc->num_usb2_ports; i++) {
> + ret = phy_power_on(dwc->usb3_generic_phy[i]);
> + if (ret < 0) {
> + /* Turn of prior ON'ed SS Phy's */
> + for (j = 0; j < i; j++)
> + phy_power_off(dwc->usb3_generic_phy[j]);
> + goto err_power_off_usb2_phy;
> + }
> + }
>
> return 0;
[..]
> +static int dwc3_get_multiport_phys(struct dwc3 *dwc)
> +{
> + int ret;
> + struct device *dev = dwc->dev;
> + int i;
> + char phy_name[11];

It would be prettier if you sorted these lines by length, longest
first...

[..]
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index d3401963bc27..84f6303922aa 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -35,6 +35,9 @@
>
> #define DWC3_MSG_MAX 500
>
> +/* Number of ports supported by a multiport controller */
> +#define MAX_PORTS_SUPPORTED 4

I think it would be preferred to prefix this DWC3_ (so perhaps just
DWC3_MAX_PORTS, to keep it shorter)

Regards,
Bjorn

> +
> /* Define XHCI Extcap register offsets for getting multiport info */
> #define XHCI_HCC_PARAMS_OFFSET 0x10
> #define DWC3_XHCI_HCSPARAMS1 0x04
> @@ -1038,8 +1041,8 @@ struct dwc3_scratchpad_array {
> * @usb3_phy: pointer to USB3 PHY
> * @num_usb2_ports: number of usb2 ports.
> * @num_usb3_ports: number of usb3 ports.
> - * @usb2_generic_phy: pointer to USB2 PHY
> - * @usb3_generic_phy: pointer to USB3 PHY
> + * @usb2_generic_phy: pointer to array of USB2 PHY
> + * @usb3_generic_phy: pointer to array of USB3 PHY
> * @phys_ready: flag to indicate that PHYs are ready
> * @ulpi: pointer to ulpi interface
> * @ulpi_ready: flag to indicate that ULPI is initialized
> @@ -1178,8 +1181,8 @@ struct dwc3 {
> u8 num_usb2_ports;
> u8 num_usb3_ports;
>
> - struct phy *usb2_generic_phy;
> - struct phy *usb3_generic_phy;
> + struct phy *usb2_generic_phy[MAX_PORTS_SUPPORTED];
> + struct phy *usb3_generic_phy[MAX_PORTS_SUPPORTED];
>
> bool phys_ready;