| Message ID | 20231212140047.2021496-2-Sanath.S@amd.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Add support for downstream port reset(DPR) | expand |
On Tue, Dec 12, 2023 at 07:30:46PM +0530, Sanath S wrote: > Introduce the tb_switch_reset_ports() function that resets the > downstream ports of a given switch. This helps us reset the USB4 > links created by boot firmware during the init sequence. > > Introduce the tb_port_reset() helper function that resets the > given port. > > Introduce the usb4_port_reset() function that performs the DPR > of a given port. This function follows the CM guide specification 7.3 > > Suggested-by: Mario Limonciello <mario.limonciello@amd.com> > Signed-off-by: Sanath S <Sanath.S@amd.com> > --- > drivers/thunderbolt/switch.c | 31 ++++++++++++++++++++++++++++ > drivers/thunderbolt/tb.h | 2 ++ > drivers/thunderbolt/tb_regs.h | 1 + > drivers/thunderbolt/usb4.c | 39 +++++++++++++++++++++++++++++++++++ > 4 files changed, 73 insertions(+) > > diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c > index 44e9b09de47a..26ad6cc1ee91 100644 > --- a/drivers/thunderbolt/switch.c > +++ b/drivers/thunderbolt/switch.c > @@ -626,6 +626,19 @@ int tb_port_unlock(struct tb_port *port) > return 0; > } > > +/** > + * tb_port_reset() - Reset downstream port > + * @port: Port to reset > + * > + * Helps to reconfigure the USB4 link by resetting the downstream port. > + * > + * Return: Returns 0 on success or an error code on failure. > + */ > +static int tb_port_reset(struct tb_port *port) > +{ > + return usb4_port_reset(port); > +} > + > static int __tb_port_enable(struct tb_port *port, bool enable) > { > int ret; > @@ -1547,6 +1560,24 @@ static void tb_dump_switch(const struct tb *tb, const struct tb_switch *sw) > regs->__unknown1, regs->__unknown4); > } > > +/** > + * tb_switch_reset_ports() - Reset downstream ports of switch. > + * @sw: Switch whose ports need to be reset. > + * > + * Return: Returns 0 on success or an error code on failure. > + */ > +int tb_switch_reset_ports(struct tb_switch *sw) > +{ > + struct tb_port *port; > + int ret = -EINVAL; Why it returns -EINVAL? What if this is run for non-USB4 router? > + > + tb_switch_for_each_port(sw, port) { > + if (tb_port_is_null(port) && port->cap_usb4) > + ret = tb_port_reset(port); Should it stop here and return ret? > + } > + return ret; > +} > + > /** > * tb_switch_reset() - reconfigure route, enable and send TB_CFG_PKG_RESET > * @sw: Switch to reset > diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h > index e299e53473ae..f2687ec4ac53 100644 > --- a/drivers/thunderbolt/tb.h > +++ b/drivers/thunderbolt/tb.h > @@ -797,6 +797,7 @@ void tb_switch_remove(struct tb_switch *sw); > void tb_switch_suspend(struct tb_switch *sw, bool runtime); > int tb_switch_resume(struct tb_switch *sw); > int tb_switch_reset(struct tb_switch *sw); > +int tb_switch_reset_ports(struct tb_switch *sw); > int tb_switch_wait_for_bit(struct tb_switch *sw, u32 offset, u32 bit, > u32 value, int timeout_msec); > void tb_sw_set_unplugged(struct tb_switch *sw); > @@ -1281,6 +1282,7 @@ struct tb_port *usb4_switch_map_usb3_down(struct tb_switch *sw, > int usb4_switch_add_ports(struct tb_switch *sw); > void usb4_switch_remove_ports(struct tb_switch *sw); > > +int usb4_port_reset(struct tb_port *port); > int usb4_port_unlock(struct tb_port *port); > int usb4_port_hotplug_enable(struct tb_port *port); > int usb4_port_configure(struct tb_port *port); > diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h > index 87e4795275fe..d49530bc0d53 100644 > --- a/drivers/thunderbolt/tb_regs.h > +++ b/drivers/thunderbolt/tb_regs.h > @@ -389,6 +389,7 @@ struct tb_regs_port_header { > #define PORT_CS_18_CSA BIT(22) > #define PORT_CS_18_TIP BIT(24) > #define PORT_CS_19 0x13 > +#define PORT_CS_19_DPR BIT(0) > #define PORT_CS_19_PC BIT(3) > #define PORT_CS_19_PID BIT(4) > #define PORT_CS_19_WOC BIT(16) > diff --git a/drivers/thunderbolt/usb4.c b/drivers/thunderbolt/usb4.c > index 4277733d0021..55f7c163bf84 100644 > --- a/drivers/thunderbolt/usb4.c > +++ b/drivers/thunderbolt/usb4.c > @@ -1073,6 +1073,45 @@ void usb4_switch_remove_ports(struct tb_switch *sw) > } > } > > +/** > + * usb4_port_reset() - Reset USB4 downsteam port > + * @port: USB4 port to reset. > + * > + * Helps to reconfigure USB4 link by resetting downstream port. > + * > + * Return: Returns 0 on success or an error code on failure. > + */ > +int usb4_port_reset(struct tb_port *port) > +{ > + int ret; > + u32 val = 0; Reverse christmas tree please: u32 val = 0; int ret; > + > + ret = tb_port_read(port, &val, TB_CFG_PORT, > + port->cap_usb4 + PORT_CS_19, 1); > + if (ret) > + return ret; > + > + val = val | PORT_CS_19_DPR; > + ret = tb_port_write(port, &val, TB_CFG_PORT, > + port->cap_usb4 + PORT_CS_19, 1); > + if (ret) > + return ret; > + > + /* Wait for 10ms after requesting downstream port reset */ > + msleep(10); Probably good to add a couple of more ms just in case. Also usleep_range()? (or fsleep()). > + > + ret = tb_port_read(port, &val, TB_CFG_PORT, > + port->cap_usb4 + PORT_CS_19, 1); > + if (ret) > + return ret; > + > + val &= ~PORT_CS_19_DPR; > + ret = tb_port_write(port, &val, TB_CFG_PORT, > + port->cap_usb4 + PORT_CS_19, 1); > + > + return ret; > +} > + > /** > * usb4_port_unlock() - Unlock USB4 downstream port > * @port: USB4 port to unlock > -- > 2.34.1
On 12/12/2023 09:27, Mika Westerberg wrote: > On Tue, Dec 12, 2023 at 07:30:46PM +0530, Sanath S wrote: >> Introduce the tb_switch_reset_ports() function that resets the >> downstream ports of a given switch. This helps us reset the USB4 >> links created by boot firmware during the init sequence. >> >> Introduce the tb_port_reset() helper function that resets the >> given port. >> >> Introduce the usb4_port_reset() function that performs the DPR >> of a given port. This function follows the CM guide specification 7.3 >> >> Suggested-by: Mario Limonciello <mario.limonciello@amd.com> >> Signed-off-by: Sanath S <Sanath.S@amd.com> >> --- >> drivers/thunderbolt/switch.c | 31 ++++++++++++++++++++++++++++ >> drivers/thunderbolt/tb.h | 2 ++ >> drivers/thunderbolt/tb_regs.h | 1 + >> drivers/thunderbolt/usb4.c | 39 +++++++++++++++++++++++++++++++++++ >> 4 files changed, 73 insertions(+) >> >> diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c >> index 44e9b09de47a..26ad6cc1ee91 100644 >> --- a/drivers/thunderbolt/switch.c >> +++ b/drivers/thunderbolt/switch.c >> @@ -626,6 +626,19 @@ int tb_port_unlock(struct tb_port *port) >> return 0; >> } >> >> +/** >> + * tb_port_reset() - Reset downstream port >> + * @port: Port to reset >> + * >> + * Helps to reconfigure the USB4 link by resetting the downstream port. >> + * >> + * Return: Returns 0 on success or an error code on failure. >> + */ >> +static int tb_port_reset(struct tb_port *port) >> +{ >> + return usb4_port_reset(port); >> +} >> + >> static int __tb_port_enable(struct tb_port *port, bool enable) >> { >> int ret; >> @@ -1547,6 +1560,24 @@ static void tb_dump_switch(const struct tb *tb, const struct tb_switch *sw) >> regs->__unknown1, regs->__unknown4); >> } >> >> +/** >> + * tb_switch_reset_ports() - Reset downstream ports of switch. >> + * @sw: Switch whose ports need to be reset. >> + * >> + * Return: Returns 0 on success or an error code on failure. >> + */ >> +int tb_switch_reset_ports(struct tb_switch *sw) >> +{ >> + struct tb_port *port; >> + int ret = -EINVAL; > > Why it returns -EINVAL? What if this is run for non-USB4 router? This is a good point, but in the non USB4 case (default return) maybe it's better to be -ENODEV and in patch 2 be careful about the caller. > >> + >> + tb_switch_for_each_port(sw, port) { >> + if (tb_port_is_null(port) && port->cap_usb4) >> + ret = tb_port_reset(port); > > Should it stop here and return ret? +1 > >> + } >> + return ret; >> +} >> + >> /** >> * tb_switch_reset() - reconfigure route, enable and send TB_CFG_PKG_RESET >> * @sw: Switch to reset >> diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h >> index e299e53473ae..f2687ec4ac53 100644 >> --- a/drivers/thunderbolt/tb.h >> +++ b/drivers/thunderbolt/tb.h >> @@ -797,6 +797,7 @@ void tb_switch_remove(struct tb_switch *sw); >> void tb_switch_suspend(struct tb_switch *sw, bool runtime); >> int tb_switch_resume(struct tb_switch *sw); >> int tb_switch_reset(struct tb_switch *sw); >> +int tb_switch_reset_ports(struct tb_switch *sw); >> int tb_switch_wait_for_bit(struct tb_switch *sw, u32 offset, u32 bit, >> u32 value, int timeout_msec); >> void tb_sw_set_unplugged(struct tb_switch *sw); >> @@ -1281,6 +1282,7 @@ struct tb_port *usb4_switch_map_usb3_down(struct tb_switch *sw, >> int usb4_switch_add_ports(struct tb_switch *sw); >> void usb4_switch_remove_ports(struct tb_switch *sw); >> >> +int usb4_port_reset(struct tb_port *port); >> int usb4_port_unlock(struct tb_port *port); >> int usb4_port_hotplug_enable(struct tb_port *port); >> int usb4_port_configure(struct tb_port *port); >> diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h >> index 87e4795275fe..d49530bc0d53 100644 >> --- a/drivers/thunderbolt/tb_regs.h >> +++ b/drivers/thunderbolt/tb_regs.h >> @@ -389,6 +389,7 @@ struct tb_regs_port_header { >> #define PORT_CS_18_CSA BIT(22) >> #define PORT_CS_18_TIP BIT(24) >> #define PORT_CS_19 0x13 >> +#define PORT_CS_19_DPR BIT(0) >> #define PORT_CS_19_PC BIT(3) >> #define PORT_CS_19_PID BIT(4) >> #define PORT_CS_19_WOC BIT(16) >> diff --git a/drivers/thunderbolt/usb4.c b/drivers/thunderbolt/usb4.c >> index 4277733d0021..55f7c163bf84 100644 >> --- a/drivers/thunderbolt/usb4.c >> +++ b/drivers/thunderbolt/usb4.c >> @@ -1073,6 +1073,45 @@ void usb4_switch_remove_ports(struct tb_switch *sw) >> } >> } >> >> +/** >> + * usb4_port_reset() - Reset USB4 downsteam port >> + * @port: USB4 port to reset. >> + * >> + * Helps to reconfigure USB4 link by resetting downstream port. >> + * >> + * Return: Returns 0 on success or an error code on failure. >> + */ >> +int usb4_port_reset(struct tb_port *port) >> +{ >> + int ret; >> + u32 val = 0; > > Reverse christmas tree please: > > u32 val = 0; > int ret; > >> + >> + ret = tb_port_read(port, &val, TB_CFG_PORT, >> + port->cap_usb4 + PORT_CS_19, 1); >> + if (ret) >> + return ret; >> + >> + val = val | PORT_CS_19_DPR; >> + ret = tb_port_write(port, &val, TB_CFG_PORT, >> + port->cap_usb4 + PORT_CS_19, 1); >> + if (ret) >> + return ret; >> + >> + /* Wait for 10ms after requesting downstream port reset */ >> + msleep(10); > > Probably good to add a couple of more ms just in case. Also > usleep_range()? (or fsleep()). Sanath had it at 20 but I had suggested to align to spec. For the wiggle room maybe usleep_range(10000, 15000)? > >> + >> + ret = tb_port_read(port, &val, TB_CFG_PORT, >> + port->cap_usb4 + PORT_CS_19, 1); >> + if (ret) >> + return ret; >> + >> + val &= ~PORT_CS_19_DPR; >> + ret = tb_port_write(port, &val, TB_CFG_PORT, >> + port->cap_usb4 + PORT_CS_19, 1); >> + >> + return ret; >> +} >> + >> /** >> * usb4_port_unlock() - Unlock USB4 downstream port >> * @port: USB4 port to unlock >> -- >> 2.34.1
On Tue, Dec 12, 2023 at 09:32:03AM -0600, Mario Limonciello wrote: > On 12/12/2023 09:27, Mika Westerberg wrote: > > On Tue, Dec 12, 2023 at 07:30:46PM +0530, Sanath S wrote: > > > Introduce the tb_switch_reset_ports() function that resets the > > > downstream ports of a given switch. This helps us reset the USB4 > > > links created by boot firmware during the init sequence. > > > > > > Introduce the tb_port_reset() helper function that resets the > > > given port. > > > > > > Introduce the usb4_port_reset() function that performs the DPR > > > of a given port. This function follows the CM guide specification 7.3 > > > > > > Suggested-by: Mario Limonciello <mario.limonciello@amd.com> > > > Signed-off-by: Sanath S <Sanath.S@amd.com> > > > --- > > > drivers/thunderbolt/switch.c | 31 ++++++++++++++++++++++++++++ > > > drivers/thunderbolt/tb.h | 2 ++ > > > drivers/thunderbolt/tb_regs.h | 1 + > > > drivers/thunderbolt/usb4.c | 39 +++++++++++++++++++++++++++++++++++ > > > 4 files changed, 73 insertions(+) > > > > > > diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c > > > index 44e9b09de47a..26ad6cc1ee91 100644 > > > --- a/drivers/thunderbolt/switch.c > > > +++ b/drivers/thunderbolt/switch.c > > > @@ -626,6 +626,19 @@ int tb_port_unlock(struct tb_port *port) > > > return 0; > > > } > > > +/** > > > + * tb_port_reset() - Reset downstream port > > > + * @port: Port to reset > > > + * > > > + * Helps to reconfigure the USB4 link by resetting the downstream port. > > > + * > > > + * Return: Returns 0 on success or an error code on failure. > > > + */ > > > +static int tb_port_reset(struct tb_port *port) > > > +{ > > > + return usb4_port_reset(port); > > > +} > > > + > > > static int __tb_port_enable(struct tb_port *port, bool enable) > > > { > > > int ret; > > > @@ -1547,6 +1560,24 @@ static void tb_dump_switch(const struct tb *tb, const struct tb_switch *sw) > > > regs->__unknown1, regs->__unknown4); > > > } > > > +/** > > > + * tb_switch_reset_ports() - Reset downstream ports of switch. > > > + * @sw: Switch whose ports need to be reset. > > > + * > > > + * Return: Returns 0 on success or an error code on failure. > > > + */ > > > +int tb_switch_reset_ports(struct tb_switch *sw) > > > +{ > > > + struct tb_port *port; > > > + int ret = -EINVAL; > > > > Why it returns -EINVAL? What if this is run for non-USB4 router? > > This is a good point, but in the non USB4 case (default return) maybe it's > better to be -ENODEV and in patch 2 be careful about the caller. Or -EOPNOTSUPP (to be consistent with the rest of the driver). Add this to the kernel-doc too so that the caller needs to make sure tb_switch_is_usb4() is called before this one or so. > > > > > > + > > > + tb_switch_for_each_port(sw, port) { > > > + if (tb_port_is_null(port) && port->cap_usb4) > > > + ret = tb_port_reset(port); > > > > Should it stop here and return ret? > > +1 > > > > > > + } > > > + return ret; > > > +} > > > + > > > /** > > > * tb_switch_reset() - reconfigure route, enable and send TB_CFG_PKG_RESET > > > * @sw: Switch to reset > > > diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h > > > index e299e53473ae..f2687ec4ac53 100644 > > > --- a/drivers/thunderbolt/tb.h > > > +++ b/drivers/thunderbolt/tb.h > > > @@ -797,6 +797,7 @@ void tb_switch_remove(struct tb_switch *sw); > > > void tb_switch_suspend(struct tb_switch *sw, bool runtime); > > > int tb_switch_resume(struct tb_switch *sw); > > > int tb_switch_reset(struct tb_switch *sw); > > > +int tb_switch_reset_ports(struct tb_switch *sw); > > > int tb_switch_wait_for_bit(struct tb_switch *sw, u32 offset, u32 bit, > > > u32 value, int timeout_msec); > > > void tb_sw_set_unplugged(struct tb_switch *sw); > > > @@ -1281,6 +1282,7 @@ struct tb_port *usb4_switch_map_usb3_down(struct tb_switch *sw, > > > int usb4_switch_add_ports(struct tb_switch *sw); > > > void usb4_switch_remove_ports(struct tb_switch *sw); > > > +int usb4_port_reset(struct tb_port *port); > > > int usb4_port_unlock(struct tb_port *port); > > > int usb4_port_hotplug_enable(struct tb_port *port); > > > int usb4_port_configure(struct tb_port *port); > > > diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h > > > index 87e4795275fe..d49530bc0d53 100644 > > > --- a/drivers/thunderbolt/tb_regs.h > > > +++ b/drivers/thunderbolt/tb_regs.h > > > @@ -389,6 +389,7 @@ struct tb_regs_port_header { > > > #define PORT_CS_18_CSA BIT(22) > > > #define PORT_CS_18_TIP BIT(24) > > > #define PORT_CS_19 0x13 > > > +#define PORT_CS_19_DPR BIT(0) > > > #define PORT_CS_19_PC BIT(3) > > > #define PORT_CS_19_PID BIT(4) > > > #define PORT_CS_19_WOC BIT(16) > > > diff --git a/drivers/thunderbolt/usb4.c b/drivers/thunderbolt/usb4.c > > > index 4277733d0021..55f7c163bf84 100644 > > > --- a/drivers/thunderbolt/usb4.c > > > +++ b/drivers/thunderbolt/usb4.c > > > @@ -1073,6 +1073,45 @@ void usb4_switch_remove_ports(struct tb_switch *sw) > > > } > > > } > > > +/** > > > + * usb4_port_reset() - Reset USB4 downsteam port > > > + * @port: USB4 port to reset. > > > + * > > > + * Helps to reconfigure USB4 link by resetting downstream port. > > > + * > > > + * Return: Returns 0 on success or an error code on failure. > > > + */ > > > +int usb4_port_reset(struct tb_port *port) > > > +{ > > > + int ret; > > > + u32 val = 0; > > > > Reverse christmas tree please: > > > > u32 val = 0; > > int ret; > > > > > + > > > + ret = tb_port_read(port, &val, TB_CFG_PORT, > > > + port->cap_usb4 + PORT_CS_19, 1); > > > + if (ret) > > > + return ret; > > > + > > > + val = val | PORT_CS_19_DPR; > > > + ret = tb_port_write(port, &val, TB_CFG_PORT, > > > + port->cap_usb4 + PORT_CS_19, 1); > > > + if (ret) > > > + return ret; > > > + > > > + /* Wait for 10ms after requesting downstream port reset */ > > > + msleep(10); > > > > Probably good to add a couple of more ms just in case. Also > > usleep_range()? (or fsleep()). > > Sanath had it at 20 but I had suggested to align to spec. > For the wiggle room maybe usleep_range(10000, 15000)? Works for me. > > > > > > + > > > + ret = tb_port_read(port, &val, TB_CFG_PORT, > > > + port->cap_usb4 + PORT_CS_19, 1); > > > + if (ret) > > > + return ret; > > > + > > > + val &= ~PORT_CS_19_DPR; > > > + ret = tb_port_write(port, &val, TB_CFG_PORT, > > > + port->cap_usb4 + PORT_CS_19, 1); > > > + > > > + return ret; > > > +} > > > + > > > /** > > > * usb4_port_unlock() - Unlock USB4 downstream port > > > * @port: USB4 port to unlock > > > -- > > > 2.34.1
diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c index 44e9b09de47a..26ad6cc1ee91 100644 --- a/drivers/thunderbolt/switch.c +++ b/drivers/thunderbolt/switch.c @@ -626,6 +626,19 @@ int tb_port_unlock(struct tb_port *port) return 0; } +/** + * tb_port_reset() - Reset downstream port + * @port: Port to reset + * + * Helps to reconfigure the USB4 link by resetting the downstream port. + * + * Return: Returns 0 on success or an error code on failure. + */ +static int tb_port_reset(struct tb_port *port) +{ + return usb4_port_reset(port); +} + static int __tb_port_enable(struct tb_port *port, bool enable) { int ret; @@ -1547,6 +1560,24 @@ static void tb_dump_switch(const struct tb *tb, const struct tb_switch *sw) regs->__unknown1, regs->__unknown4); } +/** + * tb_switch_reset_ports() - Reset downstream ports of switch. + * @sw: Switch whose ports need to be reset. + * + * Return: Returns 0 on success or an error code on failure. + */ +int tb_switch_reset_ports(struct tb_switch *sw) +{ + struct tb_port *port; + int ret = -EINVAL; + + tb_switch_for_each_port(sw, port) { + if (tb_port_is_null(port) && port->cap_usb4) + ret = tb_port_reset(port); + } + return ret; +} + /** * tb_switch_reset() - reconfigure route, enable and send TB_CFG_PKG_RESET * @sw: Switch to reset diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h index e299e53473ae..f2687ec4ac53 100644 --- a/drivers/thunderbolt/tb.h +++ b/drivers/thunderbolt/tb.h @@ -797,6 +797,7 @@ void tb_switch_remove(struct tb_switch *sw); void tb_switch_suspend(struct tb_switch *sw, bool runtime); int tb_switch_resume(struct tb_switch *sw); int tb_switch_reset(struct tb_switch *sw); +int tb_switch_reset_ports(struct tb_switch *sw); int tb_switch_wait_for_bit(struct tb_switch *sw, u32 offset, u32 bit, u32 value, int timeout_msec); void tb_sw_set_unplugged(struct tb_switch *sw); @@ -1281,6 +1282,7 @@ struct tb_port *usb4_switch_map_usb3_down(struct tb_switch *sw, int usb4_switch_add_ports(struct tb_switch *sw); void usb4_switch_remove_ports(struct tb_switch *sw); +int usb4_port_reset(struct tb_port *port); int usb4_port_unlock(struct tb_port *port); int usb4_port_hotplug_enable(struct tb_port *port); int usb4_port_configure(struct tb_port *port); diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h index 87e4795275fe..d49530bc0d53 100644 --- a/drivers/thunderbolt/tb_regs.h +++ b/drivers/thunderbolt/tb_regs.h @@ -389,6 +389,7 @@ struct tb_regs_port_header { #define PORT_CS_18_CSA BIT(22) #define PORT_CS_18_TIP BIT(24) #define PORT_CS_19 0x13 +#define PORT_CS_19_DPR BIT(0) #define PORT_CS_19_PC BIT(3) #define PORT_CS_19_PID BIT(4) #define PORT_CS_19_WOC BIT(16) diff --git a/drivers/thunderbolt/usb4.c b/drivers/thunderbolt/usb4.c index 4277733d0021..55f7c163bf84 100644 --- a/drivers/thunderbolt/usb4.c +++ b/drivers/thunderbolt/usb4.c @@ -1073,6 +1073,45 @@ void usb4_switch_remove_ports(struct tb_switch *sw) } } +/** + * usb4_port_reset() - Reset USB4 downsteam port + * @port: USB4 port to reset. + * + * Helps to reconfigure USB4 link by resetting downstream port. + * + * Return: Returns 0 on success or an error code on failure. + */ +int usb4_port_reset(struct tb_port *port) +{ + int ret; + u32 val = 0; + + ret = tb_port_read(port, &val, TB_CFG_PORT, + port->cap_usb4 + PORT_CS_19, 1); + if (ret) + return ret; + + val = val | PORT_CS_19_DPR; + ret = tb_port_write(port, &val, TB_CFG_PORT, + port->cap_usb4 + PORT_CS_19, 1); + if (ret) + return ret; + + /* Wait for 10ms after requesting downstream port reset */ + msleep(10); + + ret = tb_port_read(port, &val, TB_CFG_PORT, + port->cap_usb4 + PORT_CS_19, 1); + if (ret) + return ret; + + val &= ~PORT_CS_19_DPR; + ret = tb_port_write(port, &val, TB_CFG_PORT, + port->cap_usb4 + PORT_CS_19, 1); + + return ret; +} + /** * usb4_port_unlock() - Unlock USB4 downstream port * @port: USB4 port to unlock
Introduce the tb_switch_reset_ports() function that resets the downstream ports of a given switch. This helps us reset the USB4 links created by boot firmware during the init sequence. Introduce the tb_port_reset() helper function that resets the given port. Introduce the usb4_port_reset() function that performs the DPR of a given port. This function follows the CM guide specification 7.3 Suggested-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Sanath S <Sanath.S@amd.com> --- drivers/thunderbolt/switch.c | 31 ++++++++++++++++++++++++++++ drivers/thunderbolt/tb.h | 2 ++ drivers/thunderbolt/tb_regs.h | 1 + drivers/thunderbolt/usb4.c | 39 +++++++++++++++++++++++++++++++++++ 4 files changed, 73 insertions(+)