[PATCH] OHCI: add a quirk for ULi M5237 blocking on reset

[PATCH] OHCI: add a quirk for ULi M5237 blocking on reset

[Arseny Solokha]

From: Arseny Solokha <asolokha@kb.kras.ru>

Commit 8dccddbc2368 ("OHCI: final fix for NVIDIA problems (I hope)")
introduced into 3.1.9 broke boot on e.g. Freescale P2020DS development
board. The code path that was previously specific to NVIDIA controllers
had then become taken for all chips.

However, the M5237 installed on the board wedges solid when accessing
its base+OHCI_FMINTERVAL register, making it impossible to boot any
kernel newer than 3.1.8 on this particular and apparently other similar
machines.

Don't readl() and writel() base+OHCI_FMINTERVAL on PCI ID 10b9:5237.

The patch is suitable for the -next tree as well as all maintained
kernels up to 3.2 inclusive.

Signed-off-by: Arseny Solokha <asolokha@kb.kras.ru>
---
 drivers/usb/host/pci-quirks.c | 14 +++++++++++---
 include/linux/pci_ids.h       |  1 +
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
index 2f3aceb..3b29478 100644
--- a/drivers/usb/host/pci-quirks.c
+++ b/drivers/usb/host/pci-quirks.c
@@ -571,7 +571,7 @@ static void quirk_usb_handoff_ohci(struct pci_dev *pdev)
 {
 	void __iomem *base;
 	u32 control;
-	u32 fminterval;
+	u32 fminterval = 0;
 	int cnt;
 
 	if (!mmio_resource_enabled(pdev, 0))
@@ -619,7 +619,13 @@ static void quirk_usb_handoff_ohci(struct pci_dev *pdev)
 	}
 
 	/* software reset of the controller, preserving HcFmInterval */
-	fminterval = readl(base + OHCI_FMINTERVAL);
+	if (!(pdev->vendor == PCI_VENDOR_ID_AL &&
+	      pdev->device == PCI_DEVICE_ID_AL_M5237)) {
+		/* ULi M5237 OHCI controller (10b9:5237) locks the whole system
+		 * when accessing the OHCI_FMINTERVAL offset.
+		 */
+		fminterval = readl(base + OHCI_FMINTERVAL);
+	}
 	writel(OHCI_HCR, base + OHCI_CMDSTATUS);
 
 	/* reset requires max 10 us delay */
@@ -628,7 +634,9 @@ static void quirk_usb_handoff_ohci(struct pci_dev *pdev)
 			break;
 		udelay(1);
 	}
-	writel(fminterval, base + OHCI_FMINTERVAL);
+	if (!(pdev->vendor == PCI_VENDOR_ID_AL &&
+	      pdev->device == PCI_DEVICE_ID_AL_M5237))
+		writel(fminterval, base + OHCI_FMINTERVAL);
 
 	/* Now the controller is safely in SUSPEND and nothing can wake it up */
 	iounmap(base);
diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
index 1fa99a3..266fc5c 100644
--- a/include/linux/pci_ids.h
+++ b/include/linux/pci_ids.h
@@ -1107,6 +1107,7 @@
 #define PCI_DEVICE_ID_AL_M5219		0x5219
 #define PCI_DEVICE_ID_AL_M5228		0x5228
 #define PCI_DEVICE_ID_AL_M5229		0x5229
+#define PCI_DEVICE_ID_AL_M5237		0x5237
 #define PCI_DEVICE_ID_AL_M5451		0x5451
 #define PCI_DEVICE_ID_AL_M7101		0x7101
 
-- 
2.2.0

Re: [PATCH] OHCI: add a quirk for ULi M5237 blocking on reset

[Alan Stern]

On Fri, 5 Dec 2014, Arseny Solokha wrote:

> From: Arseny Solokha <asolokha@kb.kras.ru>
> 
> Commit 8dccddbc2368 ("OHCI: final fix for NVIDIA problems (I hope)")
> introduced into 3.1.9 broke boot on e.g. Freescale P2020DS development
> board. The code path that was previously specific to NVIDIA controllers
> had then become taken for all chips.
> 
> However, the M5237 installed on the board wedges solid when accessing
> its base+OHCI_FMINTERVAL register, making it impossible to boot any
> kernel newer than 3.1.8 on this particular and apparently other similar
> machines.
> 
> Don't readl() and writel() base+OHCI_FMINTERVAL on PCI ID 10b9:5237.

I seem to recall seeing something like this before, but I can't 
remember where or when.  At any rate, there's nothing like it in the 
current code...

> The patch is suitable for the -next tree as well as all maintained
> kernels up to 3.2 inclusive.
> 
> Signed-off-by: Arseny Solokha <asolokha@kb.kras.ru>
> ---
>  drivers/usb/host/pci-quirks.c | 14 +++++++++++---
>  include/linux/pci_ids.h       |  1 +
>  2 files changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
> index 2f3aceb..3b29478 100644
> --- a/drivers/usb/host/pci-quirks.c
> +++ b/drivers/usb/host/pci-quirks.c
> @@ -571,7 +571,7 @@ static void quirk_usb_handoff_ohci(struct pci_dev *pdev)
>  {
>  	void __iomem *base;
>  	u32 control;
> -	u32 fminterval;
> +	u32 fminterval = 0;
>  	int cnt;
>  
>  	if (!mmio_resource_enabled(pdev, 0))
> @@ -619,7 +619,13 @@ static void quirk_usb_handoff_ohci(struct pci_dev *pdev)
>  	}
>  
>  	/* software reset of the controller, preserving HcFmInterval */
> -	fminterval = readl(base + OHCI_FMINTERVAL);
> +	if (!(pdev->vendor == PCI_VENDOR_ID_AL &&
> +	      pdev->device == PCI_DEVICE_ID_AL_M5237)) {
> +		/* ULi M5237 OHCI controller (10b9:5237) locks the whole system
> +		 * when accessing the OHCI_FMINTERVAL offset.
> +		 */

You don't need to specify the vendor and device IDs in the comment.  
That's what #defines are for.

Also, the accepted format for multi-line comments is:

	/*
	 * Blah, blah, blah...
	 * Blah, blah, blah...
	 */

> +		fminterval = readl(base + OHCI_FMINTERVAL);
> +	}
>  	writel(OHCI_HCR, base + OHCI_CMDSTATUS);
>  
>  	/* reset requires max 10 us delay */
> @@ -628,7 +634,9 @@ static void quirk_usb_handoff_ohci(struct pci_dev *pdev)
>  			break;
>  		udelay(1);
>  	}
> -	writel(fminterval, base + OHCI_FMINTERVAL);
> +	if (!(pdev->vendor == PCI_VENDOR_ID_AL &&
> +	      pdev->device == PCI_DEVICE_ID_AL_M5237))
> +		writel(fminterval, base + OHCI_FMINTERVAL);

This is very ugly, with these repeated tests.  You should set a
no_fminterval flag at the start of the function and then use it instead 
of doing the same tests over again.

>  	/* Now the controller is safely in SUSPEND and nothing can wake it up */
>  	iounmap(base);
> diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
> index 1fa99a3..266fc5c 100644
> --- a/include/linux/pci_ids.h
> +++ b/include/linux/pci_ids.h
> @@ -1107,6 +1107,7 @@
>  #define PCI_DEVICE_ID_AL_M5219		0x5219
>  #define PCI_DEVICE_ID_AL_M5228		0x5228
>  #define PCI_DEVICE_ID_AL_M5229		0x5229
> +#define PCI_DEVICE_ID_AL_M5237		0x5237
>  #define PCI_DEVICE_ID_AL_M5451		0x5451
>  #define PCI_DEVICE_ID_AL_M7101		0x7101

There's no reason to add an ID to pci_ids.h if it's only going to be 
used in one source file.  Put the ID in the source file instead.

Alan Stern

[PATCH v2] OHCI: add a quirk for ULi M5237 blocking on reset

[Arseny Solokha]

From: Arseny Solokha <asolokha@kb.kras.ru>

Commit 8dccddbc2368 ("OHCI: final fix for NVIDIA problems (I hope)")
introduced into 3.1.9 broke boot on e.g. Freescale P2020DS development
board. The code path that was previously specific to NVIDIA controllers
had then become taken for all chips.

However, the M5237 installed on the board wedges solid when accessing
its base+OHCI_FMINTERVAL register, making it impossible to boot any
kernel newer than 3.1.8 on this particular and apparently other similar
machines.

Don't readl() and writel() base+OHCI_FMINTERVAL on PCI ID 10b9:5237.

The patch is suitable for the -next tree as well as all maintained
kernels up to 3.2 inclusive.

Signed-off-by: Arseny Solokha <asolokha@kb.kras.ru>
---
Changes in v2:
- review comments applied
---
 drivers/usb/host/pci-quirks.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
index 2f3aceb..f4e6b94 100644
--- a/drivers/usb/host/pci-quirks.c
+++ b/drivers/usb/host/pci-quirks.c
@@ -571,7 +571,8 @@ static void quirk_usb_handoff_ohci(struct pci_dev *pdev)
 {
 	void __iomem *base;
 	u32 control;
-	u32 fminterval;
+	u32 fminterval = 0;
+	bool no_fminterval = false;
 	int cnt;
 
 	if (!mmio_resource_enabled(pdev, 0))
@@ -581,6 +582,13 @@ static void quirk_usb_handoff_ohci(struct pci_dev *pdev)
 	if (base == NULL)
 		return;
 
+	/*
+	 * ULi M5237 OHCI controller locks the whole system when accessing
+	 * the OHCI_FMINTERVAL offset.
+	 */
+	if (pdev->vendor == PCI_VENDOR_ID_AL && pdev->device == 0x5237)
+		no_fminterval = true;
+
 	control = readl(base + OHCI_CONTROL);
 
 /* On PA-RISC, PDC can leave IR set incorrectly; ignore it there. */
@@ -619,7 +627,9 @@ static void quirk_usb_handoff_ohci(struct pci_dev *pdev)
 	}
 
 	/* software reset of the controller, preserving HcFmInterval */
-	fminterval = readl(base + OHCI_FMINTERVAL);
+	if (!no_fminterval)
+		fminterval = readl(base + OHCI_FMINTERVAL);
+
 	writel(OHCI_HCR, base + OHCI_CMDSTATUS);
 
 	/* reset requires max 10 us delay */
@@ -628,7 +638,9 @@ static void quirk_usb_handoff_ohci(struct pci_dev *pdev)
 			break;
 		udelay(1);
 	}
-	writel(fminterval, base + OHCI_FMINTERVAL);
+
+	if (!no_fminterval)
+		writel(fminterval, base + OHCI_FMINTERVAL);
 
 	/* Now the controller is safely in SUSPEND and nothing can wake it up */
 	iounmap(base);
-- 
2.2.0

Re: [PATCH v2] OHCI: add a quirk for ULi M5237 blocking on reset

[Alan Stern]

On Sat, 6 Dec 2014, Arseny Solokha wrote:

> From: Arseny Solokha <asolokha@kb.kras.ru>
> 
> Commit 8dccddbc2368 ("OHCI: final fix for NVIDIA problems (I hope)")
> introduced into 3.1.9 broke boot on e.g. Freescale P2020DS development
> board. The code path that was previously specific to NVIDIA controllers
> had then become taken for all chips.
> 
> However, the M5237 installed on the board wedges solid when accessing
> its base+OHCI_FMINTERVAL register, making it impossible to boot any
> kernel newer than 3.1.8 on this particular and apparently other similar
> machines.
> 
> Don't readl() and writel() base+OHCI_FMINTERVAL on PCI ID 10b9:5237.
> 
> The patch is suitable for the -next tree as well as all maintained
> kernels up to 3.2 inclusive.
> 
> Signed-off-by: Arseny Solokha <asolokha@kb.kras.ru>
> ---
> Changes in v2:
> - review comments applied

Much better this time.

Acked-by: Alan Stern <stern@rowland.harvard.edu>

Alan Stern

Re: [PATCH v2] OHCI: add a quirk for ULi M5237 blocking on reset

[Arseny Solokha]

> On Sat, 6 Dec 2014, Arseny Solokha wrote:
> 
>> From: Arseny Solokha <asolokha@kb.kras.ru>
>>
>> Commit 8dccddbc2368 ("OHCI: final fix for NVIDIA problems (I hope)")
>> introduced into 3.1.9 broke boot on e.g. Freescale P2020DS development
>> board. The code path that was previously specific to NVIDIA controllers
>> had then become taken for all chips.
>>
>> However, the M5237 installed on the board wedges solid when accessing
>> its base+OHCI_FMINTERVAL register, making it impossible to boot any
>> kernel newer than 3.1.8 on this particular and apparently other similar
>> machines.
>>
>> Don't readl() and writel() base+OHCI_FMINTERVAL on PCI ID 10b9:5237.
>>
>> The patch is suitable for the -next tree as well as all maintained
>> kernels up to 3.2 inclusive.
>>
>> Signed-off-by: Arseny Solokha <asolokha@kb.kras.ru>
>> ---
>> Changes in v2:
>> - review comments applied
> 
> Much better this time.
> 
> Acked-by: Alan Stern <stern@rowland.harvard.edu>

Meanwhile, I discovered a similar thread where the issue was previously
discussed, and have tried to implement a workaround suggested in [1]. No luck so
far: even if the code manages to check a value returned by
readl(base + OHCI_FMINTERVAL), it then still hangs during device unregistering.

Of course, unregistering a device instead of just not accessing OHCI_FMINTERVAL
like in my or Nikita's patch is also possible but it requires hardcoding all
flawed device IDs instead of figuring out misbehaving devices at boot time.


[1] https://lkml.org/lkml/2014/5/29/828

Arsény

Re: [PATCH v2] OHCI: add a quirk for ULi M5237 blocking on reset

[Nikita Yushchenko]

23.12.2014 08:36, Arseny Solokha пишет:
>> On Sat, 6 Dec 2014, Arseny Solokha wrote:
>>
>>> From: Arseny Solokha <asolokha@kb.kras.ru>
>>>
>>> Commit 8dccddbc2368 ("OHCI: final fix for NVIDIA problems (I hope)")
>>> introduced into 3.1.9 broke boot on e.g. Freescale P2020DS development
>>> board. The code path that was previously specific to NVIDIA controllers
>>> had then become taken for all chips.
>>>
>>> However, the M5237 installed on the board wedges solid when accessing
>>> its base+OHCI_FMINTERVAL register, making it impossible to boot any
>>> kernel newer than 3.1.8 on this particular and apparently other similar
>>> machines.
>>>
>>> Don't readl() and writel() base+OHCI_FMINTERVAL on PCI ID 10b9:5237.
>>>
>>> The patch is suitable for the -next tree as well as all maintained
>>> kernels up to 3.2 inclusive.
>>>
>>> Signed-off-by: Arseny Solokha <asolokha@kb.kras.ru>
>>> ---
>>> Changes in v2:
>>> - review comments applied
>>
>> Much better this time.
>>
>> Acked-by: Alan Stern <stern@rowland.harvard.edu>
> 
> Meanwhile, I discovered a similar thread where the issue was previously
> discussed, and have tried to implement a workaround suggested in [1]. No luck so
> far: even if the code manages to check a value returned by
> readl(base + OHCI_FMINTERVAL), it then still hangs during device unregistering.
> 
> Of course, unregistering a device instead of just not accessing OHCI_FMINTERVAL
> like in my or Nikita's patch is also possible but it requires hardcoding all
> flawed device IDs instead of figuring out misbehaving devices at boot time.

In my case root cause was elsewhere - USB port that I thought was driven
by ULI, actually was not. And ULI's builtin OHCI was not
hardware-enabled (but still was available on bus). I workarounded it by
masking entire device in platform-specific quirk.

Nikita

Re: [PATCH v2] OHCI: add a quirk for ULi M5237 blocking on reset

[Nikita Yushchenko]

> In my case root cause was elsewhere - USB port that I thought was driven
> by ULI, actually was not. And ULI's builtin OHCI was not
> hardware-enabled (but still was available on bus). I workarounded it by
> masking entire device in platform-specific quirk.

For reference, here is the patch that was finally applied to the product (3.10 based).

commit 16cf72cfa72269b55fc5c878689e00c99b640d86
Author: Nikita Yushchenko <nyoushchenko@mvista.com>
Date:   Thu Apr 3 08:35:36 2014 +0400

    powerpc: fix IRQ routing on Freescale boards with ULI1575 chip
    
    Source: MontaVista Software, LLC
    MR: 55925
    Type: Defect Fix
    Disposition: Needs submitting to mainline
    ChangeID: 1d46876594e80ef2fad575d1f4161ad2c5f0cb28
    Description:
    
    At least on some Freescale boards with ULI1575 southbridge chip,
    interrupts from PCI slots are routed to more then one IRQ input,
    causing IRQ storms when more than one path happens to be enabled.
    
    - On MPC8572DS, interrupts from PCI slots are documented to be connected
      both to SoC's IRQ inputs and to ULI1575's IRQ inputs.
    
    - On P2020DS, MPIC IRQ4 input is shared between cascade interrupt from
      ULI1575 i8259, and "Assert INTA" message from PCIe1 bus, which is
      ULI1575's upstream bus. Experiments show that with some ULI1575 IRQ
      routing settings, ULI1575 does generate "Assert INTA" message. How
      in particular this is controlled, currently is not clear. The only
      mention of such messages in 1575's datasheet is in APIC settings,
      however 1575's APIC is not used in Freescale boards.
    
    This patch does the following:
    
    - changes 1575's IRQ routing (that is currently configured in PCI quirk,
      same for all supported boards) such that
      - on boards other than P2020DS, routing from 1575's PIRQ[ABCD] is
        disabled, since interrupts from PCI slots are routed both to these
        pins and directly to SoC, and need to break one of two routes to
        avoid interrupt duplication,
      - on P2020DS, routing from PIRQA and PIRQB is kept enabled since it is
        the only path for interrupts from PCI slot,
      - routing interrupts from 1575's internal PCI devices is changed to go
        through those PIRQx that are kept enabled,
      - routing from PIRQx to i8259 inputs is configured such that, per
        experiment, "Assert INTA" messages do not appear on upstream PCIe
        bus.
    
    - updates device tree files to match new configuration,
    
    - does some related cleanup:
      - disables routing interrupts from 1575's internal devices that are
        not used in any supported boards,
      - modifies device masking to hide USB controllers on P2020DS (these
        are not disabled in hardware and thus respond to bus scans and
        appear in the system, but are not wired on the board so can't be
        used - so better to hide them completely).
    
    Signed-off-by: Nikita Yushchenko <nyoushchenko@mvista.com>
    Signed-off-by: Armin Kuster <akuster@mvista.com>

diff --git a/arch/powerpc/boot/dts/mpc8544ds.dtsi b/arch/powerpc/boot/dts/mpc8544ds.dtsi
index b219d03..fd1ac5d 100644
--- a/arch/powerpc/boot/dts/mpc8544ds.dtsi
+++ b/arch/powerpc/boot/dts/mpc8544ds.dtsi
@@ -124,13 +124,13 @@
 		interrupt-map-mask = <0xff00 0x0 0x0 0x7>;
 		interrupt-map = <
 			// IDSEL 0x1c  USB
-			0xe000 0x0 0x0 0x1 &i8259 0xc 0x2
-			0xe100 0x0 0x0 0x2 &i8259 0x9 0x2
-			0xe200 0x0 0x0 0x3 &i8259 0xa 0x2
+			0xe000 0x0 0x0 0x1 &i8259 0x5 0x2
+			0xe100 0x0 0x0 0x2 &i8259 0x6 0x2
+			0xe200 0x0 0x0 0x3 &i8259 0x7 0x2
 			0xe300 0x0 0x0 0x4 &i8259 0xb 0x2
 
 			// IDSEL 0x1d  Audio
-			0xe800 0x0 0x0 0x1 &i8259 0x6 0x2
+			0xe800 0x0 0x0 0x1 &i8259 0x7 0x2
 
 			// IDSEL 0x1e Legacy
 			0xf000 0x0 0x0 0x1 &i8259 0x7 0x2
@@ -138,7 +138,7 @@
 
 			// IDSEL 0x1f IDE/SATA
 			0xf800 0x0 0x0 0x1 &i8259 0xe 0x2
-			0xf900 0x0 0x0 0x1 &i8259 0x5 0x2
+			0xf900 0x0 0x0 0x1 &i8259 0x9 0x2
 			>;
 
 
diff --git a/arch/powerpc/boot/dts/mpc8572ds.dtsi b/arch/powerpc/boot/dts/mpc8572ds.dtsi
index 357490b..1b13572 100644
--- a/arch/powerpc/boot/dts/mpc8572ds.dtsi
+++ b/arch/powerpc/boot/dts/mpc8572ds.dtsi
@@ -343,13 +343,13 @@
 			0x9700 0x0 0x0 0x4 &mpic 0x2 0x1 0 0
 
 			// IDSEL 0x1c  USB
-			0xe000 0x0 0x0 0x1 &i8259 0xc 0x2
-			0xe100 0x0 0x0 0x2 &i8259 0x9 0x2
-			0xe200 0x0 0x0 0x3 &i8259 0xa 0x2
+			0xe000 0x0 0x0 0x1 &i8259 0x5 0x2
+			0xe100 0x0 0x0 0x2 &i8259 0x6 0x2
+			0xe200 0x0 0x0 0x3 &i8259 0x7 0x2
 			0xe300 0x0 0x0 0x4 &i8259 0xb 0x2
 
 			// IDSEL 0x1d  Audio
-			0xe800 0x0 0x0 0x1 &i8259 0x6 0x2
+			0xe800 0x0 0x0 0x1 &i8259 0x7 0x2
 
 			// IDSEL 0x1e Legacy
 			0xf000 0x0 0x0 0x1 &i8259 0x7 0x2
@@ -357,7 +357,7 @@
 
 			// IDSEL 0x1f IDE/SATA
 			0xf800 0x0 0x0 0x1 &i8259 0xe 0x2
-			0xf900 0x0 0x0 0x1 &i8259 0x5 0x2
+			0xf900 0x0 0x0 0x1 &i8259 0x9 0x2
 			>;
 
 
diff --git a/arch/powerpc/boot/dts/mpc8641_hpcn.dts b/arch/powerpc/boot/dts/mpc8641_hpcn.dts
index 1e8666c..25a08af 100644
--- a/arch/powerpc/boot/dts/mpc8641_hpcn.dts
+++ b/arch/powerpc/boot/dts/mpc8641_hpcn.dts
@@ -508,13 +508,13 @@
 			0x9700 0 0 4 &mpic 2 1
 
 			// IDSEL 0x1c  USB
-			0xe000 0 0 1 &i8259 12 2
-			0xe100 0 0 2 &i8259 9 2
-			0xe200 0 0 3 &i8259 10 2
+			0xe000 0 0 1 &i8259 5 2
+			0xe100 0 0 2 &i8259 6 2
+			0xe200 0 0 3 &i8259 7 2
 			0xe300 0 0 4 &i8259 11 2
 
 			// IDSEL 0x1d  Audio
-			0xe800 0 0 1 &i8259 6 2
+			0xe800 0 0 1 &i8259 7 2
 
 			// IDSEL 0x1e Legacy
 			0xf000 0 0 1 &i8259 7 2
@@ -522,7 +522,7 @@
 
 			// IDSEL 0x1f IDE/SATA
 			0xf800 0 0 1 &i8259 14 2
-			0xf900 0 0 1 &i8259 5 2
+			0xf900 0 0 1 &i8259 9 2
 			>;
 
 		pcie@0 {
diff --git a/arch/powerpc/boot/dts/mpc8641_hpcn_36b.dts b/arch/powerpc/boot/dts/mpc8641_hpcn_36b.dts
index fd4cd4d..60d4883 100644
--- a/arch/powerpc/boot/dts/mpc8641_hpcn_36b.dts
+++ b/arch/powerpc/boot/dts/mpc8641_hpcn_36b.dts
@@ -474,13 +474,13 @@
 			0x9700 0 0 4 &mpic 2 1
 
 			// IDSEL 0x1c  USB
-			0xe000 0 0 1 &i8259 12 2
-			0xe100 0 0 2 &i8259 9 2
-			0xe200 0 0 3 &i8259 10 2
+			0xe000 0 0 1 &i8259 5 2
+			0xe100 0 0 2 &i8259 6 2
+			0xe200 0 0 3 &i8259 7 2
 			0xe300 0 0 4 &i8259 11 2
 
 			// IDSEL 0x1d  Audio
-			0xe800 0 0 1 &i8259 6 2
+			0xe800 0 0 1 &i8259 7 2
 
 			// IDSEL 0x1e Legacy
 			0xf000 0 0 1 &i8259 7 2
@@ -488,7 +488,7 @@
 
 			// IDSEL 0x1f IDE/SATA
 			0xf800 0 0 1 &i8259 14 2
-			0xf900 0 0 1 &i8259 5 2
+			0xf900 0 0 1 &i8259 9 2
 			>;
 
 		pcie@0 {
diff --git a/arch/powerpc/boot/dts/p2020ds.dtsi b/arch/powerpc/boot/dts/p2020ds.dtsi
index 2105701..91a85ca 100644
--- a/arch/powerpc/boot/dts/p2020ds.dtsi
+++ b/arch/powerpc/boot/dts/p2020ds.dtsi
@@ -230,39 +230,39 @@
 		interrupt-map = <
 
 			// IDSEL 0x11 func 0 - PCI slot 1
-			0x8800 0x0 0x0 0x1 &i8259 0x9 0x2
+			0x8800 0x0 0x0 0x1 &i8259 0xb 0x2
 			0x8800 0x0 0x0 0x2 &i8259 0xa 0x2
 
 			// IDSEL 0x11 func 1 - PCI slot 1
-			0x8900 0x0 0x0 0x1 &i8259 0x9 0x2
+			0x8900 0x0 0x0 0x1 &i8259 0xb 0x2
 			0x8900 0x0 0x0 0x2 &i8259 0xa 0x2
 
 			// IDSEL 0x11 func 2 - PCI slot 1
-			0x8a00 0x0 0x0 0x1 &i8259 0x9 0x2
+			0x8a00 0x0 0x0 0x1 &i8259 0xb 0x2
 			0x8a00 0x0 0x0 0x2 &i8259 0xa 0x2
 
 			// IDSEL 0x11 func 3 - PCI slot 1
-			0x8b00 0x0 0x0 0x1 &i8259 0x9 0x2
+			0x8b00 0x0 0x0 0x1 &i8259 0xb 0x2
 			0x8b00 0x0 0x0 0x2 &i8259 0xa 0x2
 
 			// IDSEL 0x11 func 4 - PCI slot 1
-			0x8c00 0x0 0x0 0x1 &i8259 0x9 0x2
+			0x8c00 0x0 0x0 0x1 &i8259 0xb 0x2
 			0x8c00 0x0 0x0 0x2 &i8259 0xa 0x2
 
 			// IDSEL 0x11 func 5 - PCI slot 1
-			0x8d00 0x0 0x0 0x1 &i8259 0x9 0x2
+			0x8d00 0x0 0x0 0x1 &i8259 0xb 0x2
 			0x8d00 0x0 0x0 0x2 &i8259 0xa 0x2
 
 			// IDSEL 0x11 func 6 - PCI slot 1
-			0x8e00 0x0 0x0 0x1 &i8259 0x9 0x2
+			0x8e00 0x0 0x0 0x1 &i8259 0xb 0x2
 			0x8e00 0x0 0x0 0x2 &i8259 0xa 0x2
 
 			// IDSEL 0x11 func 7 - PCI slot 1
-			0x8f00 0x0 0x0 0x1 &i8259 0x9 0x2
+			0x8f00 0x0 0x0 0x1 &i8259 0xb 0x2
 			0x8f00 0x0 0x0 0x2 &i8259 0xa 0x2
 
 			// IDSEL 0x1d  Audio
-			0xe800 0x0 0x0 0x1 &i8259 0x6 0x2
+			0xe800 0x0 0x0 0x1 &i8259 0x7 0x2
 
 			// IDSEL 0x1e Legacy
 			0xf000 0x0 0x0 0x1 &i8259 0x7 0x2
@@ -270,7 +270,7 @@
 
 			// IDSEL 0x1f IDE/SATA
 			0xf800 0x0 0x0 0x1 &i8259 0xe 0x2
-			0xf900 0x0 0x0 0x1 &i8259 0x5 0x2
+			0xf900 0x0 0x0 0x1 &i8259 0x9 0x2
 			>;
 
 		uli1575@0 {
diff --git a/arch/powerpc/platforms/fsl_uli1575.c b/arch/powerpc/platforms/fsl_uli1575.c
index 92ac9b5..640a6fa 100644
--- a/arch/powerpc/platforms/fsl_uli1575.c
+++ b/arch/powerpc/platforms/fsl_uli1575.c
@@ -17,6 +17,7 @@
 
 #include <asm/pci-bridge.h>
 
+#define ULI_PIRQ_NONE	0x00
 #define ULI_PIRQA	0x08
 #define ULI_PIRQB	0x09
 #define ULI_PIRQC	0x0a
@@ -24,6 +25,7 @@
 #define ULI_PIRQE	0x0c
 #define ULI_PIRQF	0x0d
 #define ULI_PIRQG	0x0e
+#define ULI_PIRQH	0x0f
 
 #define ULI_8259_NONE	0x00
 #define ULI_8259_IRQ1	0x08
@@ -39,17 +41,6 @@
 #define ULI_8259_IRQ14	0x0d
 #define ULI_8259_IRQ15	0x0f
 
-u8 uli_pirq_to_irq[8] = {
-	ULI_8259_IRQ9,		/* PIRQA */
-	ULI_8259_IRQ10,		/* PIRQB */
-	ULI_8259_IRQ11,		/* PIRQC */
-	ULI_8259_IRQ12,		/* PIRQD */
-	ULI_8259_IRQ5,		/* PIRQE */
-	ULI_8259_IRQ6,		/* PIRQF */
-	ULI_8259_IRQ7,		/* PIRQG */
-	ULI_8259_NONE,		/* PIRQH */
-};
-
 static inline bool is_quirk_valid(void)
 {
 	return (machine_is(mpc86xx_hpcn) ||
@@ -84,8 +75,6 @@ static void early_uli5249(struct pci_dev *dev)
 
 static void quirk_uli1575(struct pci_dev *dev)
 {
-	int i;
-
 	if (!is_quirk_valid())
 		return;
 
@@ -93,50 +82,84 @@ static void quirk_uli1575(struct pci_dev *dev)
 	 * ULI1575 interrupts route setup
 	 */
 
-	/* ULI1575 IRQ mapping conf register maps PIRQx to IRQn */
-	for (i = 0; i < 4; i++) {
-		u8 val = uli_pirq_to_irq[i*2] | (uli_pirq_to_irq[i*2+1] << 4);
-		pci_write_config_byte(dev, 0x48 + i, val);
-	}
-
-	/* USB 1.1 OHCI controller 1: dev 28, func 0 - IRQ12 */
-	pci_write_config_byte(dev, 0x86, ULI_PIRQD);
-
-	/* USB 1.1 OHCI controller 2: dev 28, func 1 - IRQ9 */
-	pci_write_config_byte(dev, 0x87, ULI_PIRQA);
+	/* On MPC8572DS, need to disable routing from PIRQA/B/C/D,
+	 * since this is causing double-routing for interrupts that come
+	 * from PCI slots.
+	 *
+	 * On P2020DS, have to keep PIRQA and PIRQB enabled since these
+	 * get interrupts from PCI slot.
+	 *
+	 * Experiments show that some PIRQ routing settings cause 1575 to
+	 * route some interrupts using upstream bus "Assert INTx" messages.
+	 * On P2020 "Assert INTa" message causes assertion og the same MPIC
+	 * input as is used to accept i8259 cascade - causing IRQ storm.
+	 *
+	 * How generation of "Assert INTx" messages is controlled, is not
+	 * clear. The setting below is tested not to cause it.
+	 */
 
-	/* USB 1.1 OHCI controller 3: dev 28, func 2 - IRQ10 */
-	pci_write_config_byte(dev, 0x88, ULI_PIRQB);
+	/* bits 0..3 - PIRQA, bits 4..7 - PIRQB */
+	if (machine_is(p2020_ds))
+		pci_write_config_byte(dev, 0x48,
+				ULI_8259_IRQ11 | (ULI_8259_IRQ10 << 4));
+	else
+		pci_write_config_byte(dev, 0x48,
+				ULI_8259_NONE | (ULI_8259_NONE << 4));
+
+	/* bits 0..3 - PIRQC, bits 4..7 - PIRQD */
+	pci_write_config_byte(dev, 0x49, ULI_8259_NONE | (ULI_8259_NONE << 4));
+
+	/* bits 0..3 - PIRQE, bits 4..7 - PIRQF */
+	pci_write_config_byte(dev, 0x4a, ULI_8259_IRQ9 | (ULI_8259_IRQ7 << 4));
+
+	/* bits 0..3 - PIRQG, bits 4..7 - PIRQH */
+	pci_write_config_byte(dev, 0x4b, ULI_8259_IRQ6 | (ULI_8259_IRQ5 << 4));
+
+	/* On P2020DS, USB is not wired.
+	 * In othred boards, set routing
+	 *   OHCI 28:0 -> PIRQH -> IRQ5
+	 *   OHCI 28:1 -> PIRQG -> IRQ6
+	 *   OHCI 28:2 -> PIRQF -> IRQ7
+	 *   EHCI 28:3 -> IRQ11 (this is not routed via PIRQx)
+	 */
+	if (machine_is(p2020_ds)) {
+		pci_write_config_byte(dev, 0x86, ULI_PIRQ_NONE);
+		pci_write_config_byte(dev, 0x87, ULI_PIRQ_NONE);
+		pci_write_config_byte(dev, 0x88, ULI_PIRQ_NONE);
+		pci_write_config_byte(dev, 0x74, ULI_8259_NONE);
+	} else {
+		pci_write_config_byte(dev, 0x86, ULI_PIRQH);
+		pci_write_config_byte(dev, 0x87, ULI_PIRQG);
+		pci_write_config_byte(dev, 0x88, ULI_PIRQF);
+		pci_write_config_byte(dev, 0x74, ULI_8259_IRQ11);
+	}
 
-	/* Lan controller: dev 27, func 0 - IRQ6 */
-	pci_write_config_byte(dev, 0x89, ULI_PIRQF);
+	/* Lan controller 27:0 is not used on any board */
+	pci_write_config_byte(dev, 0x89, ULI_PIRQ_NONE);
 
-	/* AC97 Audio controller: dev 29, func 0 - IRQ6 */
+	/* AC97 Audio controller 29:0 -> PIRQF -> IRQ7 */
 	pci_write_config_byte(dev, 0x8a, ULI_PIRQF);
 
-	/* Modem controller: dev 29, func 1 - IRQ6 */
-	pci_write_config_byte(dev, 0x8b, ULI_PIRQF);
+	/* Modem controller 29:1 is not used on any board */
+	pci_write_config_byte(dev, 0x8b, ULI_PIRQ_NONE);
 
-	/* HD Audio controller: dev 29, func 2 - IRQ6 */
-	pci_write_config_byte(dev, 0x8c, ULI_PIRQF);
+	/* HD Audio controller 29:2 is not used on any board */
+	pci_write_config_byte(dev, 0x8c, ULI_PIRQ_NONE);
 
-	/* SATA controller: dev 31, func 1 - IRQ5 */
+	/* SATA controller 31:1 -> PIRQE -> IRQ9 */
 	pci_write_config_byte(dev, 0x8d, ULI_PIRQE);
 
-	/* SMB interrupt: dev 30, func 1 - IRQ7 */
-	pci_write_config_byte(dev, 0x8e, ULI_PIRQG);
+	/* SMB interrupt 30:1 -> PIRQF -> IRQ7 */
+	pci_write_config_byte(dev, 0x8e, ULI_PIRQF);
 
-	/* PMU ACPI SCI interrupt: dev 30, func 2 - IRQ7 */
-	pci_write_config_byte(dev, 0x8f, ULI_PIRQG);
+	/* Power management device 30:2 is not used on any board */
+	pci_write_config_byte(dev, 0x8f, ULI_PIRQ_NONE);
 
-	/* USB 2.0 controller: dev 28, func 3 */
-	pci_write_config_byte(dev, 0x74, ULI_8259_IRQ11);
-
-	/* Primary PATA IDE IRQ: 14
-	 * Secondary PATA IDE IRQ: 15
-	 */
+	/* Primary PATA IDE IRQ: 14 */
 	pci_write_config_byte(dev, 0x44, 0x30 | ULI_8259_IRQ14);
-	pci_write_config_byte(dev, 0x75, ULI_8259_IRQ15);
+
+	/* Secondary IDE is not used on any board */
+	pci_write_config_byte(dev, 0x75, ULI_8259_NONE);
 }
 
 static void quirk_final_uli1575(struct pci_dev *dev)
@@ -355,6 +378,10 @@ int uli_exclude_device(struct pci_controller *hose,
 		/* exclude HD Audio controller */
 		if ((PCI_SLOT(devfn) == 29) && (PCI_FUNC(devfn) == 2))
 			return PCIBIOS_DEVICE_NOT_FOUND;
+
+		/* exclude unwired USB on P2020DS */
+		if (machine_is(p2020_ds) && PCI_SLOT(devfn) == 28)
+			return PCIBIOS_DEVICE_NOT_FOUND;
 	}
 
 	return PCIBIOS_SUCCESSFUL;