From patchwork Tue Dec 6 15:13:41 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Finn Thain X-Patchwork-Id: 129702 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id 3AE6B100B03 for ; Wed, 7 Dec 2011 02:14:06 +1100 (EST) Received: from vps4.telegraphics.com.au (vm4.telegraphics.com.au [98.124.60.149]) by ozlabs.org (Postfix) with ESMTP id 24D781007D5 for ; Wed, 7 Dec 2011 02:13:55 +1100 (EST) Received: by vps4.telegraphics.com.au (Postfix, from userid 1003) id 3718E592319; Tue, 6 Dec 2011 10:13:46 -0500 (EST) Date: Wed, 7 Dec 2011 02:13:41 +1100 (EST) From: Finn Thain To: Geert Uytterhoeven Subject: [PATCH 01/16 v2] pmac_zilog: fix unexpected irq In-Reply-To: <20111023141115.208699274@telegraphics.com.au> Message-ID: References: <20111023141108.856998818@telegraphics.com.au> <20111023141115.208699274@telegraphics.com.au> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Cc: linux-m68k@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-serial@vger.kernel.org X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org On most 68k Macs the SCC IRQ is an autovector interrupt and cannot be masked. This can be a problem when pmac_zilog starts up. For example, the serial debugging code in arch/m68k/kernel/head.S may be used beforehand. It disables the SCC interrupts at the chip but doesn't ack them. Then when a pmac_zilog port is opened and SCC chip interrupts become enabled, the machine locks up with "unexpected interrupt" because request_irq() hasn't happened yet. Fix this by setting the interrupt enable bits only after the handler is installed and before it is uninstalled. Also move this bit flipping into a separate pmz_interrupt_control() routine. Replace all instances of these operations with calls to this routine. Signed-off-by: Finn Thain Acked-by: Alan Cox --- Re-implemented since v1 using a simpler approach that avoids messing with the Master Interrupt Enable bit. As well as the ifdef problem, it turns out that v1 was not sufficient to entirely fix the problem. This patch has been tested on a PowerBook 520 but no PowerMacs yet. Index: linux-git/drivers/tty/serial/pmac_zilog.c =================================================================== --- linux-git.orig/drivers/tty/serial/pmac_zilog.c 2011-12-07 01:56:43.000000000 +1100 +++ linux-git/drivers/tty/serial/pmac_zilog.c 2011-12-07 01:56:55.000000000 +1100 @@ -216,6 +216,18 @@ static void pmz_maybe_update_regs(struct } } +static void pmz_interrupt_control(struct uart_pmac_port *uap, int enable) +{ + if (enable) { + uap->curregs[1] |= INT_ALL_Rx | TxINT_ENAB; + if (!ZS_IS_EXTCLK(uap)) + uap->curregs[1] |= EXT_INT_ENAB; + } else { + uap->curregs[1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK); + } + write_zsreg(uap, R1, uap->curregs[1]); +} + static struct tty_struct *pmz_receive_chars(struct uart_pmac_port *uap) { struct tty_struct *tty = NULL; @@ -339,9 +351,7 @@ static struct tty_struct *pmz_receive_ch return tty; flood: - uap->curregs[R1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK); - write_zsreg(uap, R1, uap->curregs[R1]); - zssync(uap); + pmz_interrupt_control(uap, 0); pmz_error("pmz: rx irq flood !\n"); return tty; } @@ -990,12 +1000,9 @@ static int pmz_startup(struct uart_port if (ZS_IS_IRDA(uap)) pmz_irda_reset(uap); - /* Enable interrupts emission from the chip */ + /* Enable interrupt requests for the channel */ spin_lock_irqsave(&port->lock, flags); - uap->curregs[R1] |= INT_ALL_Rx | TxINT_ENAB; - if (!ZS_IS_EXTCLK(uap)) - uap->curregs[R1] |= EXT_INT_ENAB; - write_zsreg(uap, R1, uap->curregs[R1]); + pmz_interrupt_control(uap, 1); spin_unlock_irqrestore(&port->lock, flags); pmz_debug("pmz: startup() done.\n"); @@ -1015,6 +1022,25 @@ static void pmz_shutdown(struct uart_por mutex_lock(&pmz_irq_mutex); + if (!ZS_IS_ASLEEP(uap)) { + spin_lock_irqsave(&port->lock, flags); + + if (!ZS_IS_CONS(uap)) { + /* Disable receiver and transmitter */ + uap->curregs[R3] &= ~RxENABLE; + uap->curregs[R5] &= ~TxENABLE; + + /* Disable BRK assertion */ + uap->curregs[R5] &= ~SND_BRK; + pmz_maybe_update_regs(uap); + } + + /* Disable interrupt requests for the channel */ + pmz_interrupt_control(uap, 0); + + spin_unlock_irqrestore(&port->lock, flags); + } + /* Release interrupt handler */ free_irq(uap->port.irq, uap); @@ -1025,29 +1051,8 @@ static void pmz_shutdown(struct uart_por if (!ZS_IS_OPEN(uap->mate)) pmz_get_port_A(uap)->flags &= ~PMACZILOG_FLAG_IS_IRQ_ON; - /* Disable interrupts */ - if (!ZS_IS_ASLEEP(uap)) { - uap->curregs[R1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK); - write_zsreg(uap, R1, uap->curregs[R1]); - zssync(uap); - } - - if (ZS_IS_CONS(uap) || ZS_IS_ASLEEP(uap)) { - spin_unlock_irqrestore(&port->lock, flags); - mutex_unlock(&pmz_irq_mutex); - return; - } - - /* Disable receiver and transmitter. */ - uap->curregs[R3] &= ~RxENABLE; - uap->curregs[R5] &= ~TxENABLE; - - /* Disable all interrupts and BRK assertion. */ - uap->curregs[R5] &= ~SND_BRK; - pmz_maybe_update_regs(uap); - - /* Shut the chip down */ - pmz_set_scc_power(uap, 0); + if (!ZS_IS_ASLEEP(uap) && !ZS_IS_CONS(uap)) + pmz_set_scc_power(uap, 0); /* Shut the chip down */ spin_unlock_irqrestore(&port->lock, flags); @@ -1352,19 +1357,15 @@ static void pmz_set_termios(struct uart_ spin_lock_irqsave(&port->lock, flags); /* Disable IRQs on the port */ - uap->curregs[R1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK); - write_zsreg(uap, R1, uap->curregs[R1]); + pmz_interrupt_control(uap, 0); /* Setup new port configuration */ __pmz_set_termios(port, termios, old); /* Re-enable IRQs on the port */ - if (ZS_IS_OPEN(uap)) { - uap->curregs[R1] |= INT_ALL_Rx | TxINT_ENAB; - if (!ZS_IS_EXTCLK(uap)) - uap->curregs[R1] |= EXT_INT_ENAB; - write_zsreg(uap, R1, uap->curregs[R1]); - } + if (ZS_IS_OPEN(uap)) + pmz_interrupt_control(uap, 1); + spin_unlock_irqrestore(&port->lock, flags); } @@ -1670,15 +1671,13 @@ static int pmz_suspend(struct macio_dev spin_lock_irqsave(&uap->port.lock, flags); + /* Disable receiver and transmitter. */ + uap->curregs[R3] &= ~RxENABLE; + uap->curregs[R5] &= ~TxENABLE; + + pmz_interrupt_control(uap, 0); + if (ZS_IS_OPEN(uap) || ZS_IS_CONS(uap)) { - /* Disable receiver and transmitter. */ - uap->curregs[R3] &= ~RxENABLE; - uap->curregs[R5] &= ~TxENABLE; - - /* Disable all interrupts and BRK assertion. */ - uap->curregs[R1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK); - uap->curregs[R5] &= ~SND_BRK; - pmz_load_zsregs(uap, uap->curregs); uap->flags |= PMACZILOG_FLAG_IS_ASLEEP; mb(); } @@ -1738,14 +1737,6 @@ static int pmz_resume(struct macio_dev * /* Take care of config that may have changed while asleep */ __pmz_set_termios(&uap->port, &uap->termios_cache, NULL); - if (ZS_IS_OPEN(uap)) { - /* Enable interrupts */ - uap->curregs[R1] |= INT_ALL_Rx | TxINT_ENAB; - if (!ZS_IS_EXTCLK(uap)) - uap->curregs[R1] |= EXT_INT_ENAB; - write_zsreg(uap, R1, uap->curregs[R1]); - } - spin_unlock_irqrestore(&uap->port.lock, flags); if (ZS_IS_CONS(uap)) @@ -1757,6 +1748,12 @@ static int pmz_resume(struct macio_dev * enable_irq(uap->port.irq); } + if (ZS_IS_OPEN(uap)) { + spin_lock_irqsave(&uap->port.lock, flags); + pmz_interrupt_control(uap, 1); + spin_unlock_irqrestore(&uap->port.lock, flags); + } + bail: mutex_unlock(&state->port.mutex); mutex_unlock(&pmz_irq_mutex);