Patchwork pata_bf54x: fix BMIDE status register emulation

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Submitter Zhang, Sonic
Date Jan. 4, 2012, 6:04 a.m.
Message ID <DB904C5425BA6F4E8424B3B51A1414D16D76860EA1@NWD2CMBX1.ad.analog.com>
Download mbox | patch
Permalink /patch/134208/
State Not Applicable
Delegated to: David Miller
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Comments

Zhang, Sonic - Jan. 4, 2012, 6:04 a.m.
Hi Serge,

The MULTI_DONE_INT, UDMAIN_DONE_INT and UDMAOUT_DONE_INT are triggered independent of the ATAPI_DEV_INT, although they bind to the same IRQ on bf548. With your patch, these interrupts are ignored and results in kernel error "unhandled IRQ".

If you insist the BMDMA emulation on bf548 should comply with INF-8038i. I would propose the following patch to disable all BF548 ATAPI specific interrupts.


Sonic


---
 drivers/ata/pata_bf54x.c |   19 ++-----------------
 1 files changed, 2 insertions(+), 17 deletions(-)

--
1.7.0.4



-----Original Message-----
From: Sergei Shtylyov [mailto:sshtylyov@mvista.com]
Sent: Saturday, December 31, 2011 11:06 PM
To: Zhang, Sonic
Cc: Sergei Shtylyov; linux-ide@vger.kernel.org; jgarzik@pobox.com
Subject: Re: [PATCH] pata_bf54x: fix BMIDE status register emulation

Hello.

On 31-12-2011 7:22, Zhang, Sonic wrote:

> Hi Shtylyov,

    I prefer Sergei.
    And please wrap your messages at 80 characters or less.

> After I review the BF54x ATAPI and DMA spec again, I have to NAK your following patch.
> The BF54x ATAPI DMA controller doesn't comply with INF-8038i.

    If you are emulating SFF-8038i register interface (which you are doing by
implementing "bmdma" set of libata methods -- and bmdma_status() method in
perticular), you *have to comply*. Either comply, or don't do it at all.

> Interrupts MULTI_DONE_INT, UDMAIN_DONE_INT and UDMAOUT_DONE_INT are generated by BF54x ATAPI host controller. They also indicate the completion of various types of ATAPI transfers.  So do interrupts MULTI_TERM_INT, UDMAIN_TERM_INT and UDMAOUT_TERM_INT, which indicate the device termination of the ATAPI DMA transfer.

    Device can only terminate DMA burst at which point it's up to the host
controller to decide whether it was the last burst or not. This can only be
done with the help of the signals external to DMA interfacem, i.e. INTRQ.

> In BF54x hardware reference manual:

> After servicing the interrupt source associated with a bit, the user must
> clear that interrupt source bit. ATA_DEV_INT is the interrupt generated by
> the device. The rest of the interrupts are generated by the host. Either the
> device or the host interrupt can be used by the firmware.

> The PIO_DONE_INT, MULTI_DONE_INT, ULTRA_IN_DONE_INT, and
> ULTRA_OUT_DONE_INT (W1C) bits indicate that interrupts have been
> asserted on completion of various types of transfers.

> The MULTI_TERM_INT (W1C) bit indicates that the interrupt has been
> asserted on device terminate of the multiword DMA transfer.

> The ULTRA_IN_TERM_INT and ULTRA_OUT_TERM_INT (W1C) bits indicate
> that interrupts have been asserted on device termination of ultra DMA in
> or out transfers.

    I have read all that... it doesn't justify your NAK in any way. Just test
the patch and report the result.

> Sonic

> -----Original Message-----
> From: Sergei Shtylyov [mailto:sshtylyov@ru.mvista.com]
> Sent: Wednesday, December 28, 2011 11:37 PM
> To: linux-ide@vger.kernel.org; jgarzik@pobox.com; Zhang, Sonic
> Subject: [PATCH] pata_bf54x: fix BMIDE status register emulation
>
> The author of this driver clearly wasn't familiar with the BMIDE specification
> (also known as SFF-8038i) when he implemented the bmdma_status() method: first,
> the interrupt bit of the BMIDE status register corresponds to nothing else but
> INTRQ signal (ATAPI_DEV_INT here); second, the error bit is only set if the
> controller encounters issue doing the bus master transfers, not on the DMA burst
> termination interrupts like here (moreover, setting the error bit doesn't cause
> an interrupt).
>
> (The only thing I couldn't figure out is how to flush the FIFO to memory once
> the interrupt happens as required by the mentioned spec.)
>
> Signed-off-by: Sergei Shtylyov<sshtylyov@ru.mvista.com>
>
> ---
> The patch is against the current Linus' tree.
> Sonic, if you still work in Analog Devices, please give this a try.
>
> I looked over the driver, and it left pretty bad impression. In particular,
> I highly doubt that the transfers with more than one S/G item can work. And
> this is after the driver has been in the kernel for 4 years already...
> Unfortunately, I have neither hardware nor much time to work on improving it...
>
>   drivers/ata/pata_bf54x.c |    8 ++------
>   1 file changed, 2 insertions(+), 6 deletions(-)
>
> Index: linux-2.6/drivers/ata/pata_bf54x.c
> ===================================================================
> --- linux-2.6.orig/drivers/ata/pata_bf54x.c
> +++ linux-2.6/drivers/ata/pata_bf54x.c
> @@ -1153,15 +1153,11 @@ static unsigned char bfin_bmdma_status(s
>   {
>          unsigned char host_stat = 0;
>          void __iomem *base = (void __iomem *)ap->ioaddr.ctl_addr;
> -       unsigned short int_status = ATAPI_GET_INT_STATUS(base);
>
> -       if (ATAPI_GET_STATUS(base)&  (MULTI_XFER_ON|ULTRA_XFER_ON))
> +       if (ATAPI_GET_STATUS(base)&  (MULTI_XFER_ON | ULTRA_XFER_ON))
>                  host_stat |= ATA_DMA_ACTIVE;
> -       if (int_status&  (MULTI_DONE_INT|UDMAIN_DONE_INT|UDMAOUT_DONE_INT|
> -               ATAPI_DEV_INT))
> +       if (ATAPI_GET_INT_STATUS(base)&  ATAPI_DEV_INT)
>                  host_stat |= ATA_DMA_INTR;
> -       if (int_status&  (MULTI_TERM_INT|UDMAIN_TERM_INT|UDMAOUT_TERM_INT))
> -               host_stat |= ATA_DMA_ERR|ATA_DMA_INTR;
>
>          dev_dbg(ap->dev, "ATAPI: host_stat=0x%x\n", host_stat);


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Sergei Shtylyov - Jan. 4, 2012, 1:21 p.m.
Hello.

On 04-01-2012 10:04, Zhang, Sonic wrote:

> Hi Serge,

> The MULTI_DONE_INT, UDMAIN_DONE_INT and UDMAOUT_DONE_INT are triggered independent
> of the ATAPI_DEV_INT, although they bind to the same IRQ on bf548. With your patch,
 > these interrupts are ignored and results in kernel error "unhandled IRQ".

    Ah, indeed...

> If you insist the BMDMA emulation on bf548 should comply with INF-8038i.

    It's not that I insist. It clearly follows from libata implemeting 
bmdma_status() method.

> I would propose the following patch to disable all BF548 ATAPI specific interrupts.

    Yes, I agree -- they don't seem needed. And that will simplify the driver 
too. I'll recast the patch and add your signoff if you agree.

> Sonic

> ---
>   drivers/ata/pata_bf54x.c |   19 ++-----------------
>   1 files changed, 2 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/ata/pata_bf54x.c b/drivers/ata/pata_bf54x.c
> index bd987bb..9711c2a 100644
> --- a/drivers/ata/pata_bf54x.c
> +++ b/drivers/ata/pata_bf54x.c
> @@ -418,14 +418,6 @@ static void bfin_set_dmamode(struct ata_port *ap, struct ata_device *adev)
>                                          (tcyc_tdvs<<8 | tdvs));
>                                  ATAPI_SET_ULTRA_TIM_2(base, (tmli<<8 | tss));
>                                  ATAPI_SET_ULTRA_TIM_3(base, (trp<<8 | tzah));
> -
> -                               /* Enable host ATAPI Untra DMA interrupts */
> -                               ATAPI_SET_INT_MASK(base,
> -                                       ATAPI_GET_INT_MASK(base)
> -                                       | UDMAIN_DONE_MASK
> -                                       | UDMAOUT_DONE_MASK
> -                                       | UDMAIN_TERM_MASK
> -                                       | UDMAOUT_TERM_MASK);
>                          }
>                  }
>          }
> @@ -470,10 +462,6 @@ static void bfin_set_dmamode(struct ata_port *ap, struct ata_device *adev)
>                          ATAPI_SET_MULTI_TIM_0(base, (tm<<8 | td));
>                          ATAPI_SET_MULTI_TIM_1(base, (tkr<<8 | tkw));
>                          ATAPI_SET_MULTI_TIM_2(base, (teoc<<8 | th));
> -
> -                       /* Enable host ATAPI Multi DMA interrupts */
> -                       ATAPI_SET_INT_MASK(base, ATAPI_GET_INT_MASK(base)
> -                               | MULTI_DONE_MASK | MULTI_TERM_MASK);
>                          SSYNC();
>                  }
>          }
> @@ -1155,13 +1143,10 @@ static unsigned char bfin_bmdma_status(struct ata_port *ap)
>          void __iomem *base = (void __iomem *)ap->ioaddr.ctl_addr;
>          unsigned short int_status = ATAPI_GET_INT_STATUS(base);
>
> -       if (ATAPI_GET_STATUS(base)&  (MULTI_XFER_ON|ULTRA_XFER_ON))
> +       if (ATAPI_GET_STATUS(base)&  (MULTI_XFER_ON | ULTRA_XFER_ON))
>                  host_stat |= ATA_DMA_ACTIVE;
> -       if (int_status&  (MULTI_DONE_INT|UDMAIN_DONE_INT|UDMAOUT_DONE_INT|
> -               ATAPI_DEV_INT))
> +       if (ATAPI_GET_INT_STATUS(base)&  ATAPI_DEV_INT)
>                  host_stat |= ATA_DMA_INTR;
> -       if (int_status&  (MULTI_TERM_INT|UDMAIN_TERM_INT|UDMAOUT_TERM_INT))
> -               host_stat |= ATA_DMA_ERR|ATA_DMA_INTR;
>
>          dev_dbg(ap->dev, "ATAPI: host_stat=0x%x\n", host_stat);
>
> --
> 1.7.0.4

WBR, Sergei
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Sonic Zhang - Jan. 5, 2012, 2:45 a.m.
On Wed, Jan 4, 2012 at 9:21 PM, Sergei Shtylyov <sshtylyov@mvista.com> wrote:
> Hello.
>
>
> On 04-01-2012 10:04, Zhang, Sonic wrote:
>
>> Hi Serge,
>
>
>> The MULTI_DONE_INT, UDMAIN_DONE_INT and UDMAOUT_DONE_INT are triggered
>> independent
>> of the ATAPI_DEV_INT, although they bind to the same IRQ on bf548. With
>> your patch,
>
>> these interrupts are ignored and results in kernel error "unhandled IRQ".
>
>   Ah, indeed...
>
>
>> If you insist the BMDMA emulation on bf548 should comply with INF-8038i.
>
>
>   It's not that I insist. It clearly follows from libata implemeting
> bmdma_status() method.
>
>
>> I would propose the following patch to disable all BF548 ATAPI specific
>> interrupts.
>
>
>   Yes, I agree -- they don't seem needed. And that will simplify the driver
> too. I'll recast the patch and add your signoff if you agree.

No problem.

Sonic

>
>> Sonic
>
>
>> ---
>>  drivers/ata/pata_bf54x.c |   19 ++-----------------
>>  1 files changed, 2 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/ata/pata_bf54x.c b/drivers/ata/pata_bf54x.c
>> index bd987bb..9711c2a 100644
>> --- a/drivers/ata/pata_bf54x.c
>> +++ b/drivers/ata/pata_bf54x.c
>> @@ -418,14 +418,6 @@ static void bfin_set_dmamode(struct ata_port *ap,
>> struct ata_device *adev)
>>                                         (tcyc_tdvs<<8 | tdvs));
>>                                 ATAPI_SET_ULTRA_TIM_2(base, (tmli<<8 |
>> tss));
>>                                 ATAPI_SET_ULTRA_TIM_3(base, (trp<<8 |
>> tzah));
>> -
>> -                               /* Enable host ATAPI Untra DMA interrupts
>> */
>> -                               ATAPI_SET_INT_MASK(base,
>> -                                       ATAPI_GET_INT_MASK(base)
>> -                                       | UDMAIN_DONE_MASK
>> -                                       | UDMAOUT_DONE_MASK
>> -                                       | UDMAIN_TERM_MASK
>> -                                       | UDMAOUT_TERM_MASK);
>>                         }
>>                 }
>>         }
>> @@ -470,10 +462,6 @@ static void bfin_set_dmamode(struct ata_port *ap,
>> struct ata_device *adev)
>>                         ATAPI_SET_MULTI_TIM_0(base, (tm<<8 | td));
>>                         ATAPI_SET_MULTI_TIM_1(base, (tkr<<8 | tkw));
>>                         ATAPI_SET_MULTI_TIM_2(base, (teoc<<8 | th));
>> -
>> -                       /* Enable host ATAPI Multi DMA interrupts */
>> -                       ATAPI_SET_INT_MASK(base, ATAPI_GET_INT_MASK(base)
>> -                               | MULTI_DONE_MASK | MULTI_TERM_MASK);
>>                         SSYNC();
>>                 }
>>         }
>> @@ -1155,13 +1143,10 @@ static unsigned char bfin_bmdma_status(struct
>> ata_port *ap)
>>         void __iomem *base = (void __iomem *)ap->ioaddr.ctl_addr;
>>         unsigned short int_status = ATAPI_GET_INT_STATUS(base);
>>
>> -       if (ATAPI_GET_STATUS(base)&  (MULTI_XFER_ON|ULTRA_XFER_ON))
>> +       if (ATAPI_GET_STATUS(base)&  (MULTI_XFER_ON | ULTRA_XFER_ON))
>>                 host_stat |= ATA_DMA_ACTIVE;
>> -       if (int_status&  (MULTI_DONE_INT|UDMAIN_DONE_INT|UDMAOUT_DONE_INT|
>> -               ATAPI_DEV_INT))
>> +       if (ATAPI_GET_INT_STATUS(base)&  ATAPI_DEV_INT)
>>                 host_stat |= ATA_DMA_INTR;
>> -       if (int_status&
>>  (MULTI_TERM_INT|UDMAIN_TERM_INT|UDMAOUT_TERM_INT))
>> -               host_stat |= ATA_DMA_ERR|ATA_DMA_INTR;
>>
>>         dev_dbg(ap->dev, "ATAPI: host_stat=0x%x\n", host_stat);
>>
>> --
>> 1.7.0.4
>
>
> WBR, Sergei
>
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Sergei Shtylyov - Jan. 6, 2012, 5:14 p.m.
Hello.

On 01/04/2012 09:04 AM, Zhang, Sonic wrote:

> The MULTI_DONE_INT, UDMAIN_DONE_INT and UDMAOUT_DONE_INT are triggered independent of the ATAPI_DEV_INT, although they bind to the same IRQ on bf548. With your patch, these interrupts are ignored and results in kernel error "unhandled IRQ".

> If you insist the BMDMA emulation on bf548 should comply with INF-8038i. I would propose the following patch to disable all BF548 ATAPI specific interrupts.

> Sonic


> ---
>   drivers/ata/pata_bf54x.c |   19 ++-----------------
>   1 files changed, 2 insertions(+), 17 deletions(-)

> diff --git a/drivers/ata/pata_bf54x.c b/drivers/ata/pata_bf54x.c
> index bd987bb..9711c2a 100644
> --- a/drivers/ata/pata_bf54x.c
> +++ b/drivers/ata/pata_bf54x.c
> @@ -418,14 +418,6 @@ static void bfin_set_dmamode(struct ata_port *ap, struct ata_device *adev)
>                                          (tcyc_tdvs<<8 | tdvs));
>                                  ATAPI_SET_ULTRA_TIM_2(base, (tmli<<8 | tss));
>                                  ATAPI_SET_ULTRA_TIM_3(base, (trp<<8 | tzah));
> -
> -                               /* Enable host ATAPI Untra DMA interrupts */
> -                               ATAPI_SET_INT_MASK(base,
> -                                       ATAPI_GET_INT_MASK(base)
> -                                       | UDMAIN_DONE_MASK
> -                                       | UDMAOUT_DONE_MASK
> -                                       | UDMAIN_TERM_MASK
> -                                       | UDMAOUT_TERM_MASK);
>                          }
>                  }
>          }
> @@ -470,10 +462,6 @@ static void bfin_set_dmamode(struct ata_port *ap, struct ata_device *adev)
>                          ATAPI_SET_MULTI_TIM_0(base, (tm<<8 | td));
>                          ATAPI_SET_MULTI_TIM_1(base, (tkr<<8 | tkw));
>                          ATAPI_SET_MULTI_TIM_2(base, (teoc<<8 | th));
> -
> -                       /* Enable host ATAPI Multi DMA interrupts */
> -                       ATAPI_SET_INT_MASK(base, ATAPI_GET_INT_MASK(base)
> -                               | MULTI_DONE_MASK | MULTI_TERM_MASK);
>                          SSYNC();
>                  }
>          }
> @@ -1155,13 +1143,10 @@ static unsigned char bfin_bmdma_status(struct ata_port *ap)
>          void __iomem *base = (void __iomem *)ap->ioaddr.ctl_addr;
>          unsigned short int_status = ATAPI_GET_INT_STATUS(base);
>
> -       if (ATAPI_GET_STATUS(base)&  (MULTI_XFER_ON|ULTRA_XFER_ON))
> +       if (ATAPI_GET_STATUS(base)&  (MULTI_XFER_ON | ULTRA_XFER_ON))
>                  host_stat |= ATA_DMA_ACTIVE;
> -       if (int_status&  (MULTI_DONE_INT|UDMAIN_DONE_INT|UDMAOUT_DONE_INT|
> -               ATAPI_DEV_INT))
> +       if (ATAPI_GET_INT_STATUS(base)&  ATAPI_DEV_INT)
>                  host_stat |= ATA_DMA_INTR;
> -       if (int_status&  (MULTI_TERM_INT|UDMAIN_TERM_INT|UDMAOUT_TERM_INT))
> -               host_stat |= ATA_DMA_ERR|ATA_DMA_INTR;
>
>          dev_dbg(ap->dev, "ATAPI: host_stat=0x%x\n", host_stat);
>

    Unfortunately your patch is white space damaged, with tabs converted to 
spaces. I'll reconstruct it...

MBR, Sergei
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Patch

diff --git a/drivers/ata/pata_bf54x.c b/drivers/ata/pata_bf54x.c
index bd987bb..9711c2a 100644
--- a/drivers/ata/pata_bf54x.c
+++ b/drivers/ata/pata_bf54x.c
@@ -418,14 +418,6 @@  static void bfin_set_dmamode(struct ata_port *ap, struct ata_device *adev)
                                        (tcyc_tdvs<<8 | tdvs));
                                ATAPI_SET_ULTRA_TIM_2(base, (tmli<<8 | tss));
                                ATAPI_SET_ULTRA_TIM_3(base, (trp<<8 | tzah));
-
-                               /* Enable host ATAPI Untra DMA interrupts */
-                               ATAPI_SET_INT_MASK(base,
-                                       ATAPI_GET_INT_MASK(base)
-                                       | UDMAIN_DONE_MASK
-                                       | UDMAOUT_DONE_MASK
-                                       | UDMAIN_TERM_MASK
-                                       | UDMAOUT_TERM_MASK);
                        }
                }
        }
@@ -470,10 +462,6 @@  static void bfin_set_dmamode(struct ata_port *ap, struct ata_device *adev)
                        ATAPI_SET_MULTI_TIM_0(base, (tm<<8 | td));
                        ATAPI_SET_MULTI_TIM_1(base, (tkr<<8 | tkw));
                        ATAPI_SET_MULTI_TIM_2(base, (teoc<<8 | th));
-
-                       /* Enable host ATAPI Multi DMA interrupts */
-                       ATAPI_SET_INT_MASK(base, ATAPI_GET_INT_MASK(base)
-                               | MULTI_DONE_MASK | MULTI_TERM_MASK);
                        SSYNC();
                }
        }
@@ -1155,13 +1143,10 @@  static unsigned char bfin_bmdma_status(struct ata_port *ap)
        void __iomem *base = (void __iomem *)ap->ioaddr.ctl_addr;
        unsigned short int_status = ATAPI_GET_INT_STATUS(base);

-       if (ATAPI_GET_STATUS(base) & (MULTI_XFER_ON|ULTRA_XFER_ON))
+       if (ATAPI_GET_STATUS(base) & (MULTI_XFER_ON | ULTRA_XFER_ON))
                host_stat |= ATA_DMA_ACTIVE;
-       if (int_status & (MULTI_DONE_INT|UDMAIN_DONE_INT|UDMAOUT_DONE_INT|
-               ATAPI_DEV_INT))
+       if (ATAPI_GET_INT_STATUS(base) & ATAPI_DEV_INT)
                host_stat |= ATA_DMA_INTR;
-       if (int_status & (MULTI_TERM_INT|UDMAIN_TERM_INT|UDMAOUT_TERM_INT))
-               host_stat |= ATA_DMA_ERR|ATA_DMA_INTR;

        dev_dbg(ap->dev, "ATAPI: host_stat=0x%x\n", host_stat);