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SubjectRe: [PATCH v9 03/10] usb: dwc3: core: Access XHCI address space temporarily to read port info
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On 6/27/2023 5:15 PM, Johan Hovold wrote:
> On Wed, Jun 21, 2023 at 10:06:21AM +0530, Krishna Kurapati wrote:
>> Currently host-only capable DWC3 controllers support Multiport.
>> Temporarily map XHCI address space for host-only controllers and parse
>> XHCI Extended Capabilities registers to read number of usb2 ports and
>> usb3 ports present on multiport controller. Each USB Port is at least HS
>> capable.
>>
>> The port info for usb2 and usb3 phy are identified as num_usb2_ports
>> and num_usb3_ports. The intention is as follows:
>>
>> Wherever we need to perform phy operations like:
>>
>> LOOP_OVER_NUMBER_OF_AVAILABLE_PORTS()
>> {
>> phy_set_mode(dwc->usb2_generic_phy[i], PHY_MODE_USB_HOST);
>> phy_set_mode(dwc->usb3_generic_phy[i], PHY_MODE_USB_HOST);
>> }
>>
>> If number of usb2 ports is 3, loop can go from index 0-2 for
>> usb2_generic_phy. If number of usb3-ports is 2, we don't know for sure,
>> if the first 2 ports are SS capable or some other ports like (2 and 3)
>> are SS capable. So instead, num_usb2_ports is used to loop around all
>> phy's (both hs and ss) for performing phy operations. If any
>> usb3_generic_phy turns out to be NULL, phy operation just bails out.
>>
>> num_usb3_ports is used to modify GUSB3PIPECTL registers while setting up
>> phy's as we need to know how many SS capable ports are there for this.
>>
>> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
>> ---
>> drivers/usb/dwc3/core.c | 62 +++++++++++++++++++++++++++++++++++++++++
>> drivers/usb/dwc3/core.h | 9 ++++++
>> 2 files changed, 71 insertions(+)
>>
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index f6689b731718..32ec05fc242b 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -39,6 +39,7 @@
>> #include "io.h"
>>
>> #include "debug.h"
>> +#include "../host/xhci-ext-caps.h"
>>
>> #define DWC3_DEFAULT_AUTOSUSPEND_DELAY 5000 /* ms */
>>
>> @@ -1767,6 +1768,52 @@ static int dwc3_get_clocks(struct dwc3 *dwc)
>> return 0;
>> }
>>
>> +static int dwc3_read_port_info(struct dwc3 *dwc)
>> +{
>> + void __iomem *base;
>> + u8 major_revision;
>> + u32 offset = 0;
>> + int ret = 0;
>
> ret is never modified, so drop and return 0 unconditionally below.
>
> You can add it back later in the series when you start using it.
>
>> + u32 val;
>> +
>> + /*
>> + * Remap xHCI address space to access XHCI ext cap regs,
>> + * since it is needed to get port info.
>> + */
>> + base = ioremap(dwc->xhci_resources[0].start,
>> + resource_size(&dwc->xhci_resources[0]));
>> + if (IS_ERR(base))
>> + return PTR_ERR(base);
>> +
>> + do {
>> + offset = xhci_find_next_ext_cap(base, offset,
>> + XHCI_EXT_CAPS_PROTOCOL);
>> +
>
> You can drop this newline.
>
>> + 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_err(dwc->dev,
>> + "Unrecognized port major revision %d\n",
>> + major_revision);
>> + }
>> + } while (1);
>> +
>> + dev_dbg(dwc->dev, "hs-ports: %u ss-ports: %u\n",
>> + dwc->num_usb2_ports, dwc->num_usb3_ports);
>> +
>> + iounmap(base);
>
> Nit: I'd add a newline here.
>
>> + return ret;
>> +}
>> +
>> static int dwc3_probe(struct platform_device *pdev)
>> {
>> struct device *dev = &pdev->dev;
>> @@ -1774,6 +1821,7 @@ static int dwc3_probe(struct platform_device *pdev)
>> void __iomem *regs;
>> struct dwc3 *dwc;
>> int ret;
>> + unsigned int hw_mode;
>>
>> dwc = devm_kzalloc(dev, sizeof(*dwc), GFP_KERNEL);
>> if (!dwc)
>> @@ -1854,6 +1902,20 @@ static int dwc3_probe(struct platform_device *pdev)
>> goto err_disable_clks;
>> }
>>
>> + /*
>> + * Currently only DWC3 controllers that are host-only capable
>> + * support Multiport.
>> + */
>> + 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;
>> + }
>> +
>> spin_lock_init(&dwc->lock);
>> mutex_init(&dwc->mutex);
>>
>> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
>> index 8b1295e4dcdd..42fb17aa66fa 100644
>> --- a/drivers/usb/dwc3/core.h
>> +++ b/drivers/usb/dwc3/core.h
>> @@ -33,6 +33,10 @@
>>
>> #include <linux/power_supply.h>
>>
>> +#define XHCI_EXT_PORT_MAJOR(x) (((x) >> 24) & 0xff)
>> +#define XHCI_EXT_PORT_MINOR(x) (((x) >> 16) & 0xff)
>> +#define XHCI_EXT_PORT_COUNT(x) (((x) >> 8) & 0xff)
>
> Again, don't copy defines from xhci.
>
> Looks like these should be moved to the xhci-ext-caps.h header along
> with struct xhci_protocol_caps.
>
Can't we just give them an exception ? Modifying xhci stuff doesn't
sound good. Can I just rename them and keep them here ?

Regards,
Krishna,

>> +
>> #define DWC3_MSG_MAX 500
>>
>> /* Global constants */
>> @@ -1029,6 +1033,8 @@ struct dwc3_scratchpad_array {
>> * @usb3_phy: pointer to USB3 PHY
>> * @usb2_generic_phy: pointer to USB2 PHY
>> * @usb3_generic_phy: pointer to USB3 PHY
>> + * @num_usb2_ports: number of USB2 ports.
>> + * @num_usb3_ports: number of USB3 ports.
>
> Again, please drop the full stops ('.').
>
> Johan

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