Messages in this thread | | | Date | Tue, 12 Dec 2023 09:32:03 -0600 | Subject | Re: [PATCH 1/2] thunderbolt: Introduce tb_switch_reset_ports(), tb_port_reset() and usb4_port_reset() | From | Mario Limonciello <> |
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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
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