From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="ZdO1yfHz" Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.13]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DCD0695; Tue, 12 Dec 2023 07:41:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1702395669; x=1733931669; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=kZ6hvomjTCYe68qbVXiiPSpyzF165YdGy6Q7vZP6y80=; b=ZdO1yfHzts9gL/OHocgUnzzkvhUkCeztyfHAmWsGJZvOi3x6rmZ2DMnG TS26DMZQXRYeCE8ghWpTi0ahI+MzXjz3mq5j5yutF5cPZpiveP7WT8/9h HYk6IguSp2eXShiRcp8saMRd/soSgISkbei+M0obk2yLk/GwCdXbA4vo8 nQrbSvSRCV01hVk1cIoLWJ4zKWVUZogJwIbnur4/AE11cffFVmtu0Z9yS ufV11zQUeQ6mmuZ/NYtdG4vA6Coa40ior8ReGipRiIRd1+r2Wovn2P84s mRKqk/LbTLEUA/9fx0Rr4H+D61s55cid5KUD4uJpf0V57B6KIsKDzBzmB Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10922"; a="1903332" X-IronPort-AV: E=Sophos;i="6.04,270,1695711600"; d="scan'208";a="1903332" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Dec 2023 07:41:08 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10922"; a="777137588" X-IronPort-AV: E=Sophos;i="6.04,270,1695711600"; d="scan'208";a="777137588" Received: from black.fi.intel.com ([10.237.72.28]) by fmsmga007.fm.intel.com with ESMTP; 12 Dec 2023 07:41:06 -0800 Received: by black.fi.intel.com (Postfix, from userid 1001) id E19453D2; Tue, 12 Dec 2023 17:41:04 +0200 (EET) Date: Tue, 12 Dec 2023 17:41:04 +0200 From: Mika Westerberg To: Mario Limonciello Cc: Sanath S , andreas.noever@gmail.com, michael.jamet@intel.com, YehezkelShB@gmail.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] thunderbolt: Introduce tb_switch_reset_ports(), tb_port_reset() and usb4_port_reset() Message-ID: <20231212154104.GH1074920@black.fi.intel.com> References: <20231212140047.2021496-1-Sanath.S@amd.com> <20231212140047.2021496-2-Sanath.S@amd.com> <20231212152706.GG1074920@black.fi.intel.com> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: 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 > > > Signed-off-by: Sanath S > > > --- > > > 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