From patchwork Wed Oct 4 08:38:00 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Cave-Ayland X-Patchwork-Id: 13408389 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 848F6E8FDDA for ; Wed, 4 Oct 2023 08:41:07 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qnxPY-0004wm-EB; Wed, 04 Oct 2023 04:39:16 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qnxPU-0004lN-MY for qemu-devel@nongnu.org; Wed, 04 Oct 2023 04:39:13 -0400 Received: from mail.ilande.co.uk ([2001:41c9:1:41f::167]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qnxPS-0007iS-Nx for qemu-devel@nongnu.org; Wed, 04 Oct 2023 04:39:12 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=ilande.co.uk; s=20220518; h=Subject:Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:To:From:Sender:Reply-To:Cc: Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=HNSsg9W015GHn8O4DJQUIfZYim9fHWmcUO3YSEGY3G8=; b=mx/1FsVMsucngy4RiEs3Ws+NYv UTeTtfI9TRt3i+iBjyD+siQCDEW5cMkxQgL6Eq8gytjRYK7puInO1Sfd+yX6OHYpEtWJmRXNJrbKO RBplOLPhu98Z7FfSCS0Anzc8gTvewDw3zcMxcmgFybDWOb0+/v+nEeqBHjXoOa8BOkDcs5r9AcyPs amHHcYHNi+jgOyTiG50P6Pg4bGuk9LvDrgsW0qxCfinw0hLsL83AZ3Ftuv2wSaabDMLlqhYyBK/A/ W1ds5JXFCEgzl4Te45JTqqA+WPpKweS6mJH/Q9HWGmilPUGkafHE+YbETtCwaLM/9oEUxPByyjyyr Yy+gQ68airoK+R9n/zqNKWTeYEnHvHsBt8Wj3Ol00YT/vfz1ewrdVqF08go5Tv7roUUKThlDq7yVp zh0s9Jq/aH0fagafa0wyfqo4i5FLIpB4Ru9eiOcp/QATXdTRDnIkEZxJdFc884LU27lmC2pdG5L7G JX0++WwV5vXayl414bvFVdVg9vYKriGcl88S0CgvdSvBocpesyvokRZV7mc7a0xgRVOZx+/O5qo3X zGKsU+Y6G5s3/8XQfftT+yrYLEtB72pWWXp832AYj7lVOo0bR+YTxiHR23wAl86DeVTqG6hJ+2WFu Qmxin7TWcJO9KDGGWQBzJcUFIe0e38KU5NLutrSU0=; Received: from host86-159-123-68.range86-159.btcentralplus.com ([86.159.123.68] helo=localhost.localdomain) by mail.ilande.co.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1qnxPD-0006za-4p; Wed, 04 Oct 2023 09:38:59 +0100 From: Mark Cave-Ayland To: laurent@vivier.eu, qemu-devel@nongnu.org Date: Wed, 4 Oct 2023 09:38:00 +0100 Message-Id: <20231004083806.757242-15-mark.cave-ayland@ilande.co.uk> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231004083806.757242-1-mark.cave-ayland@ilande.co.uk> References: <20231004083806.757242-1-mark.cave-ayland@ilande.co.uk> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 86.159.123.68 X-SA-Exim-Mail-From: mark.cave-ayland@ilande.co.uk Subject: [PATCH v4 14/20] mac_via: work around underflow in TimeDBRA timing loop in SETUPTIMEK X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on mail.ilande.co.uk) Received-SPF: pass client-ip=2001:41c9:1:41f::167; envelope-from=mark.cave-ayland@ilande.co.uk; helo=mail.ilande.co.uk X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org The MacOS toolbox ROM calculates the number of branches that can be executed per millisecond as part of its timer calibration. Since modern hosts are considerably quicker than original hardware, the negative counter reaches zero before the calibration completes leading to division by zero later in CALCULATESLOD. Instead of trying to fudge the timing loop (which won't work for TimeDBRA/TimeSCCDB anyhow), use the pattern of access to the VIA1 registers to detect when SETUPTIMEK has finished executing and write some well-known good timer values to TimeDBRA and TimeSCCDB taken from real hardware with a suitable scaling factor. Signed-off-by: Mark Cave-Ayland Reviewed-by: Laurent Vivier --- hw/misc/mac_via.c | 115 ++++++++++++++++++++++++++++++++++++++ hw/misc/trace-events | 1 + include/hw/misc/mac_via.h | 3 + 3 files changed, 119 insertions(+) diff --git a/hw/misc/mac_via.c b/hw/misc/mac_via.c index e87a1b82d8..f2ccb12d64 100644 --- a/hw/misc/mac_via.c +++ b/hw/misc/mac_via.c @@ -16,6 +16,7 @@ */ #include "qemu/osdep.h" +#include "exec/address-spaces.h" #include "migration/vmstate.h" #include "hw/sysbus.h" #include "hw/irq.h" @@ -871,6 +872,112 @@ static void via1_auxmode_update(MOS6522Q800VIA1State *v1s) } } +/* + * Addresses and real values for TimeDBRA/TimeSCCB to allow timer calibration + * to succeed (NOTE: both values have been multiplied by 3 to cope with the + * speed of QEMU execution on a modern host + */ +#define MACOS_TIMEDBRA 0xd00 +#define MACOS_TIMESCCB 0xd02 + +#define MACOS_TIMEDBRA_VALUE (0x2a00 * 3) +#define MACOS_TIMESCCB_VALUE (0x079d * 3) + +static bool via1_is_toolbox_timer_calibrated(void) +{ + /* + * Indicate whether the MacOS toolbox has been calibrated by checking + * for the value of our magic constants + */ + uint16_t timedbra = lduw_be_phys(&address_space_memory, MACOS_TIMEDBRA); + uint16_t timesccdb = lduw_be_phys(&address_space_memory, MACOS_TIMESCCB); + + return (timedbra == MACOS_TIMEDBRA_VALUE && + timesccdb == MACOS_TIMESCCB_VALUE); +} + +static void via1_timer_calibration_hack(MOS6522Q800VIA1State *v1s, int addr, + uint64_t val, int size) +{ + /* + * Work around timer calibration to ensure we that we have non-zero and + * known good values for TIMEDRBA and TIMESCCDB. + * + * This works by attempting to detect the reset and calibration sequence + * of writes to VIA1 + */ + int old_timer_hack_state = v1s->timer_hack_state; + + switch (v1s->timer_hack_state) { + case 0: + if (addr == VIA_REG_PCR && val == 0x22) { + /* VIA_REG_PCR: configure VIA1 edge triggering */ + v1s->timer_hack_state = 1; + } + break; + case 1: + if (addr == VIA_REG_T2CL && val == 0xc) { + /* VIA_REG_T2CL: low byte of 1ms counter */ + if (!via1_is_toolbox_timer_calibrated()) { + v1s->timer_hack_state = 2; + } else { + v1s->timer_hack_state = 0; + } + } + break; + case 2: + if (addr == VIA_REG_T2CH && val == 0x3) { + /* + * VIA_REG_T2CH: high byte of 1ms counter (very likely at the + * start of SETUPTIMEK) + */ + if (!via1_is_toolbox_timer_calibrated()) { + v1s->timer_hack_state = 3; + } else { + v1s->timer_hack_state = 0; + } + } + break; + case 3: + if (addr == VIA_REG_IER && val == 0x20) { + /* + * VIA_REG_IER: update at end of SETUPTIMEK + * + * Timer calibration has finished: unfortunately the values in + * TIMEDBRA (0xd00) and TIMESCCDB (0xd02) are so far out they + * cause divide by zero errors. + * + * Update them with values obtained from a real Q800 but with + * a x3 scaling factor which seems to work well + */ + stw_be_phys(&address_space_memory, MACOS_TIMEDBRA, + MACOS_TIMEDBRA_VALUE); + stw_be_phys(&address_space_memory, MACOS_TIMESCCB, + MACOS_TIMESCCB_VALUE); + + v1s->timer_hack_state = 4; + } + break; + case 4: + /* + * This is the normal post-calibration timer state: we should + * generally remain here unless we detect the A/UX calibration + * loop, or a write to VIA_REG_PCR suggesting a reset + */ + if (addr == VIA_REG_PCR && val == 0x22) { + /* Looks like there has been a reset? */ + v1s->timer_hack_state = 1; + } + break; + default: + g_assert_not_reached(); + } + + if (old_timer_hack_state != v1s->timer_hack_state) { + trace_via1_timer_hack_state(v1s->timer_hack_state); + } +} + static uint64_t mos6522_q800_via1_read(void *opaque, hwaddr addr, unsigned size) { MOS6522Q800VIA1State *s = MOS6522_Q800_VIA1(opaque); @@ -896,6 +1003,9 @@ static void mos6522_q800_via1_write(void *opaque, hwaddr addr, uint64_t val, MOS6522State *ms = MOS6522(v1s); addr = (addr >> 9) & 0xf; + + via1_timer_calibration_hack(v1s, addr, val, size); + mos6522_write(ms, addr, val, size); switch (addr) { @@ -1008,6 +1118,9 @@ static void mos6522_q800_via1_reset_hold(Object *obj) adb_set_autopoll_enabled(adb_bus, true); v1s->cmd = REG_EMPTY; v1s->alt = REG_EMPTY; + + /* Timer calibration hack */ + v1s->timer_hack_state = 0; } static void mos6522_q800_via1_realize(DeviceState *dev, Error **errp) @@ -1100,6 +1213,8 @@ static const VMStateDescription vmstate_q800_via1 = { VMSTATE_INT64(next_second, MOS6522Q800VIA1State), VMSTATE_TIMER_PTR(sixty_hz_timer, MOS6522Q800VIA1State), VMSTATE_INT64(next_sixty_hz, MOS6522Q800VIA1State), + /* Timer hack */ + VMSTATE_INT32(timer_hack_state, MOS6522Q800VIA1State), VMSTATE_END_OF_LIST() } }; diff --git a/hw/misc/trace-events b/hw/misc/trace-events index 29bc531d4d..5a998f5e4e 100644 --- a/hw/misc/trace-events +++ b/hw/misc/trace-events @@ -272,6 +272,7 @@ via1_adb_send(const char *state, uint8_t data, const char *vadbint) "state %s da via1_adb_receive(const char *state, uint8_t data, const char *vadbint, int status, int index, int size) "state %s data=0x%02x vADBInt=%s status=0x%x index=%d size=%d" via1_adb_poll(uint8_t data, const char *vadbint, int status, int index, int size) "data=0x%02x vADBInt=%s status=0x%x index=%d size=%d" via1_auxmode(int mode) "setting auxmode to %d" +via1_timer_hack_state(int state) "setting timer_hack_state to %d" # grlib_ahb_apb_pnp.c grlib_ahb_pnp_read(uint64_t addr, unsigned size, uint32_t value) "AHB PnP read addr:0x%03"PRIx64" size:%u data:0x%08x" diff --git a/include/hw/misc/mac_via.h b/include/hw/misc/mac_via.h index 422da43bf9..63cdcf7c69 100644 --- a/include/hw/misc/mac_via.h +++ b/include/hw/misc/mac_via.h @@ -74,6 +74,9 @@ struct MOS6522Q800VIA1State { int64_t next_second; QEMUTimer *sixty_hz_timer; int64_t next_sixty_hz; + + /* SETUPTIMEK hack */ + int timer_hack_state; };