Attachment 152683 Details for Bug 233011 – dwmw2-bcm43xx-mac80211-debug.patch

[patch] dwmw2-bcm43xx-mac80211-debug.patch

dwmw2-bcm43xx-mac80211-debug.patch (text/plain), 2.67 KB, created by John W. Linville on 2007-04-16 13:35:28 UTC

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Creator: John W. Linville

Created: 2007-04-16 13:35:28 UTC

Size: 2.67 KB

patch

obsolete

>Subject: Re: [PATCH] bcm43xx-mac80211: Fix machine checks on PPC with rev 1
>	PHYs
>From: David Woodhouse <dwmw2@infradead.org>
>To: Larry Finger <larry.finger@lwfinger.net>
>Cc: "John W. Linville" <linville@tuxdriver.com>,
>        linux-wireless@vger.kernel.org, Bcm43xx-dev@lists.berlios.de,
>        Michael Buesch <mb@bu3sch.de>
>Date: Mon, 16 Apr 2007 02:04:07 +0100
>
>On Thu, 2007-04-12 at 20:22 -0500, Larry Finger wrote:
>> Your tester needs to get a copy of David's hack that prints out the address of the offending 
>> register. That is the only way to tell what is happening. Once we know the address, then it will be 
>> a matter of getting printk's into the code to tell which one is failing. 
>
>It's very simple... if we use inw instead of readw for the faulting I/O
>access, then the machine check gets trapped. We can do this because on
>PPC, PCI I/O is actually memory-mapped. The CPU doesn't have a separate
>I/O space and instructions. So we just compensate for the address at
>which PCI I/O is mapped, and abuse inw().
>
>Then we make bcm43xx_phy_read() print the register it tried to access
>whenever it gets 0xFFFF, and stick a WARN_ON(1) in the machine check
>handler when it detects a machine check caused by an I/O access...
>
>--- ./drivers/net/wireless/mac80211/bcm43xx/bcm43xx_phy.c	2007-04-14 21:51:02.000000000 +0100
>+++ ./drivers/net/wireless/mac80211/bcm43xx/bcm43xx_phy.c	2007-04-16 01:39:44.000000000 +0100
>@@ -269,10 +270,13 @@ static inline u16 adjust_phyreg_for_phyt
> u16 bcm43xx_phy_read(struct bcm43xx_wldev *dev, u16 offset)
> {
> 	struct bcm43xx_phy *phy = &dev->phy;
>-
>+	uint16_t foo;
> 	offset = adjust_phyreg_for_phytype(phy, offset);
> 	bcm43xx_write16(dev, BCM43xx_MMIO_PHY_CONTROL, offset);
>-	return bcm43xx_read16(dev, BCM43xx_MMIO_PHY_DATA);
>+	foo = bcm43xx_read16(dev, BCM43xx_MMIO_PHY_DATA);
>+	if (foo == 0xffff)
>+		printk(KERN_DEBUG "Read phy reg %x; got 0xFFFF.\n", offset);
>+	return foo;
> }
> 
> void bcm43xx_phy_write(struct bcm43xx_wldev *dev, u16 offset, u16 val)
>--- ./drivers/ssb/pci.c	2007-04-14 21:51:02.000000000 +0100
>+++ ./drivers/ssb/pci.c	2007-04-15 23:44:27.000000000 +0100
>@@ -475,6 +475,7 @@ static u16 ssb_pci_read16(struct ssb_dev
> 		if (unlikely(ssb_pci_switch_core(bus, dev)))
> 			return 0xFFFF;
> 	}
>+	return inw(bus->mmio + offset - isa_io_base);
> 	return readw(bus->mmio + offset);
> }
> 
>--- ./arch/powerpc/kernel/traps.c	2007-04-14 21:50:40.000000000 +0100
>+++ ./arch/powerpc/kernel/traps.c	2007-04-15 23:45:48.000000000 +0100
>@@ -343,8 +343,10 @@ void machine_check_exception(struct pt_r
> 		return;
> 	}
> 
>-	if (check_io_access(regs))
>+	if (check_io_access(regs)) {
>+		WARN_ON(1);
> 		return;
>+	}
> 
> #if defined(CONFIG_4xx) && !defined(CONFIG_440A)
> 	if (reason & ESR_IMCP) {
>
>-- 
>dwmw2
>

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