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[23.128.96.18]) by mx.google.com with ESMTP id k1si1918560edf.460.2020.11.06.15.15.28; Fri, 06 Nov 2020 15:15:52 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@fnarfbargle.com header.s=mail header.b=FIJcEwpH; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=fnarfbargle.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729029AbgKFXNn (ORCPT + 99 others); Fri, 6 Nov 2020 18:13:43 -0500 Received: from ns3.fnarfbargle.com ([103.4.19.87]:39972 "EHLO ns3.fnarfbargle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728968AbgKFXNn (ORCPT ); Fri, 6 Nov 2020 18:13:43 -0500 Received: from srv.home ([10.8.0.1] ident=heh14179) by ns3.fnarfbargle.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.84_2) (envelope-from ) id 1kbAsu-0001PN-QL; Sat, 07 Nov 2020 07:11:08 +0800 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=fnarfbargle.com; s=mail; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject; bh=IJg9I3sWXQAFqOIxVldrvYtfCazCCY50HuwEBx1IZOw=; b=FIJcEwpHR4v/SdQD18zDk6T91eoRBXOpEOGvhb6MMTiNEYOHmj8C2odeDdMGQDPXdaNVHFRzXUH8OvEZV+pt+wH3cDv3WMbnxvrVyN4y9UlM7WLwjwTLiGIchU2WG4wR6GbbBLDPTeesuJRZmWDtlO5rphyAb/MG3Ybkbl6LdOk=; Subject: Re: [PATCH] applesmc: Re-work SMC comms v2 To: Henrik Rydberg Cc: Arnd Bergmann , linux-hwmon@vger.kernel.org, "linux-kernel@vger.kernel.org" , hns@goldelico.com, Guenter Roeck , Andreas Kemnade , Jean Delvare References: <20200930105442.3f642f6c@aktux> <20200930164446.GB219887@roeck-us.net> <20201002002251.28462e64@aktux> <7543ef85-727d-96c3-947e-5b18e9e6c44d@roeck-us.net> <20201006090226.4275c824@kemnade.info> <68467f1b-cea1-47ea-a4d4-8319214b072a@fnarfbargle.com> <20201104142057.62493c12@aktux> <2436afef-99c6-c352-936d-567bf553388c@fnarfbargle.com> <7a085650-2399-08c0-3c4d-6cd1fa28a365@roeck-us.net> <10027199-5d31-93e7-9bd8-7baaebff8b71@roeck-us.net> <70331f82-35a1-50bd-685d-0b06061dd213@fnarfbargle.com> <3c72ccc3-4de1-b5d0-423d-7b8c80991254@fnarfbargle.com> <6d071547-10ee-ca92-ec8b-4b5069d04501@bitmath.org> <8e117844-d62a-bcb1-398d-c59cc0d4b878@fnarfbargle.com> From: Brad Campbell Message-ID: <4405a9f5-49d2-b162-8b70-8479a4d9705c@fnarfbargle.com> Date: Sat, 7 Nov 2020 10:11:09 +1100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.2.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/11/20 3:26 am, Henrik Rydberg wrote: >>> I can't guarantee it won't break older machines which is why I've asked for help testing it. I only have a MacbookPro 11,1 and an iMac 12,2. It fixes both of those. >>> >>> Help testing would be much appreciated. >> >> I see, this makes much more sense. I may be able to run some tests tonight. Meanwhile, looking at the patch, the status variable in send_command looks superfluous now that there is a wait_status() before it. > > Ok, it took some time to get the machines up to speed, but so far I have managed to run some tests on an MacBookAir1,1. I only managed to upgrade up to 4.15, so I had to revert the inputdev polling patch, but the rest applied without problems. I recovered an old test program I used to use (attached), and checked for failures and reads per second > > *** hwmon: (applesmc) switch to using input device polling mode > > At this point in the tree, with this reverted, I see 0 failures and 55 reads per second. > > *** hwmon: (applesmc) avoid overlong udelay() > > With this applied, I see 0 failures and 16 reads per second. > > *** hwmon: (applesmc) check status earlier. > > With this applied, I see 0 failures and 16 reads per second. > > *** (HEAD -> stable) applesmc: Re-work SMC comms v2 > > With this applied, the kernel hangs in module probe, and the kernel log is flooded with read failures. > > So as it stands, it does not work at all. I will continue to check another machine, and see if I can get something working. > > Henrik G'day Heinrik, If you could try this earlier version which still had all the failure logging it in we might be able to get a handle on the failure. Regards, Brad --- diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c index a18887990f4a..22cc5122ce9a 100644 --- a/drivers/hwmon/applesmc.c +++ b/drivers/hwmon/applesmc.c @@ -42,6 +42,11 @@ #define APPLESMC_MAX_DATA_LENGTH 32 +/* Apple SMC status bits from VirtualSMC */ +#define SMC_STATUS_AWAITING_DATA 0x01 ///< Data waiting to be read +#define SMC_STATUS_IB_CLOSED 0x02 /// A write is pending / will ignore input +#define SMC_STATUS_BUSY 0x04 ///< Busy in the middle of a command. + /* wait up to 128 ms for a status change. */ #define APPLESMC_MIN_WAIT 0x0010 #define APPLESMC_RETRY_WAIT 0x0100 @@ -151,65 +156,77 @@ static unsigned int key_at_index; static struct workqueue_struct *applesmc_led_wq; /* - * wait_read - Wait for a byte to appear on SMC port. Callers must - * hold applesmc_lock. + * Wait for specific status bits with a mask on the SMC + * Used before and after writes, and before reads */ -static int wait_read(void) + +static int wait_status(u8 val, u8 mask) { unsigned long end = jiffies + (APPLESMC_MAX_WAIT * HZ) / USEC_PER_SEC; u8 status; int us; for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) { - usleep_range(us, us * 16); status = inb(APPLESMC_CMD_PORT); - /* read: wait for smc to settle */ - if (status & 0x01) + if ((status & mask) == val) return 0; /* timeout: give up */ if (time_after(jiffies, end)) break; - } - - pr_warn("wait_read() fail: 0x%02x\n", status); + usleep_range(us, us * 16); + } + pr_warn("wait_status timeout: 0x%02x, 0x%02x, 0x%02x\n", status, val, mask); return -EIO; } /* - * send_byte - Write to SMC port, retrying when necessary. Callers + * send_byte_data - Write to SMC data port. Callers * must hold applesmc_lock. + * Parameter skip must be true on the last write of any + * command or it'll time out. */ -static int send_byte(u8 cmd, u16 port) + +static int send_byte_data(u8 cmd, u16 port, bool skip) { - u8 status; - int us; - unsigned long end = jiffies + (APPLESMC_MAX_WAIT * HZ) / USEC_PER_SEC; + u8 wstat = SMC_STATUS_BUSY; + if (skip) + wstat = 0; + if (wait_status(SMC_STATUS_BUSY, + SMC_STATUS_BUSY | SMC_STATUS_IB_CLOSED)) + goto fail; outb(cmd, port); - for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) { - usleep_range(us, us * 16); - status = inb(APPLESMC_CMD_PORT); - /* write: wait for smc to settle */ - if (status & 0x02) - continue; - /* ready: cmd accepted, return */ - if (status & 0x04) - return 0; - /* timeout: give up */ - if (time_after(jiffies, end)) - break; - /* busy: long wait and resend */ - udelay(APPLESMC_RETRY_WAIT); - outb(cmd, port); - } - - pr_warn("send_byte(0x%02x, 0x%04x) fail: 0x%02x\n", cmd, port, status); + if (!wait_status(wstat, + SMC_STATUS_BUSY)) + return 0; +fail: + pr_warn("send_byte_data(0x%02x, 0x%04x) fail\n", cmd, APPLESMC_CMD_PORT); return -EIO; } +/* + * send_command - Write a command to the SMC. Callers must hold applesmc_lock. + * If SMC is in undefined state, any new command write resets the state machine. + */ + static int send_command(u8 cmd) { - return send_byte(cmd, APPLESMC_CMD_PORT); + u8 status; + + if (wait_status(0, + SMC_STATUS_IB_CLOSED)) { + pr_warn("send_command SMC was busy\n"); + goto fail; } + + status = inb(APPLESMC_CMD_PORT); + + outb(cmd, APPLESMC_CMD_PORT); + if (!wait_status(SMC_STATUS_BUSY, + SMC_STATUS_BUSY)) + return 0; +fail: + pr_warn("send_cmd(0x%02x, 0x%04x) fail\n", cmd, APPLESMC_CMD_PORT); + return -EIO; } static int send_argument(const char *key) @@ -217,7 +234,8 @@ static int send_argument(const char *key) int i; for (i = 0; i < 4; i++) - if (send_byte(key[i], APPLESMC_DATA_PORT)) + /* Parameter skip is false as we always send data after an argument */ + if (send_byte_data(key[i], APPLESMC_DATA_PORT, false)) return -EIO; return 0; } @@ -233,13 +251,15 @@ static int read_smc(u8 cmd, const char *key, u8 *buffer, u8 len) } /* This has no effect on newer (2012) SMCs */ - if (send_byte(len, APPLESMC_DATA_PORT)) { + if (send_byte_data(len, APPLESMC_DATA_PORT, false)) { pr_warn("%.4s: read len fail\n", key); return -EIO; } for (i = 0; i < len; i++) { - if (wait_read()) { + if (wait_status(SMC_STATUS_AWAITING_DATA | SMC_STATUS_BUSY, + SMC_STATUS_AWAITING_DATA | SMC_STATUS_BUSY | + SMC_STATUS_IB_CLOSED)) { pr_warn("%.4s: read data[%d] fail\n", key, i); return -EIO; } @@ -250,7 +270,7 @@ static int read_smc(u8 cmd, const char *key, u8 *buffer, u8 len) for (i = 0; i < 16; i++) { udelay(APPLESMC_MIN_WAIT); status = inb(APPLESMC_CMD_PORT); - if (!(status & 0x01)) + if (!(status & SMC_STATUS_AWAITING_DATA)) break; data = inb(APPLESMC_DATA_PORT); } @@ -263,20 +283,21 @@ static int read_smc(u8 cmd, const char *key, u8 *buffer, u8 len) static int write_smc(u8 cmd, const char *key, const u8 *buffer, u8 len) { int i; + u8 end = len-1; if (send_command(cmd) || send_argument(key)) { pr_warn("%s: write arg fail\n", key); return -EIO; } - if (send_byte(len, APPLESMC_DATA_PORT)) { + if (send_byte_data(len, APPLESMC_DATA_PORT, false)) { pr_warn("%.4s: write len fail\n", key); return -EIO; } for (i = 0; i < len; i++) { - if (send_byte(buffer[i], APPLESMC_DATA_PORT)) { - pr_warn("%s: write data fail\n", key); + if (send_byte_data(buffer[i], APPLESMC_DATA_PORT, (i == end))) { + pr_warn("%s: write data fail at %i\n", key, i); return -EIO; } }