Re: ata, pcmcia: problem with irq and ata_dev_read_id()

[Heiko Schocher <hs@denx.de>]

Hello Robert,

Robert Hancock wrote:
> On 05/30/2010 11:57 PM, Heiko Schocher wrote:
>> Hello Jeff,
>>
>> I have ported Linux 2.6.34 for a 8xx based board using the m8xx_pcmcia.c
>> driver in drivers/pcmcia/ with two slots and CONFIG_ATA,
>> CONFIG_PATA_PCMCIA
>> defined.
>>
>> All works fine, except with one CF card type, I get:
>>
>> rtc-pcf8563 0-0051: setting system clock to 2010-05-31 05:18:41 UTC
>> (1275283121)
>> pcmcia_socket pcmcia_socket0: pccard: PCMCIA card inserted into slot 0
>> pcmcia 0.0: pcmcia: registering new device pcmcia0.0
>> scsi0 : pata_pcmcia
>> ata1: PATA max PIO4 cmd 0x0 ctl 0xe irq 25
>> ata1.00: CFA: TOSHIBA THNCF512MDG, 3.00, max MWDMA2
>> ata1.00: 1000944 sectors, multi 1: LBA
>> ata1.00: configured for PIO4
>> ata1.00: configured for PIO4
>> ata1: EH complete
>> isa bounce pool size: 16 pages
>> scsi 0:0:0:0: Direct-Access     ATA      TOSHIBA THNCF512 3.00 PQ: 0
>> ANSI: 5
>> sd 0:0:0:0: [sda] 1000944 512-byte logical blocks: (512 MB/488 MiB)
>> sd 0:0:0:0: [sda] Write Protect is off
>> sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't
>> support DPO or FUA
>>   sda: sda1 sda2 sda3 sda4
>> pcmcia_socket pcmcia_socket1: pccard: PCMCIA card inserted into slot 1
>> pcmcia 1.0: pcmcia: registering new device pcmcia1.0
>> sd 0:0:0:0: [sda] Attached SCSI removable disk
>> scsi1 : pata_pcmcia
>> ata2: PATA max PIO4 cmd 0x10 ctl 0x1e irq 26
>> irq 26: nobody cared (try booting with the "irqpoll" option)
>> Call Trace:
>> [c0327c70] [c0006ac0] show_stack+0x44/0x16c (unreliable)
>> [c0327cb0] [c004b7b4] __report_bad_irq+0x34/0xb8
>> [c0327cd0] [c004b9f0] note_interrupt+0x1b8/0x224
>> [c0327d00] [c004c9a8] handle_level_irq+0xa8/0x124
>> [c0327d10] [c0004de8] do_IRQ+0x98/0xb4
>> [c0327d30] [c000e788] ret_from_except+0x0/0x14
>> [c0327df0] [00009032] 0x9032
>> [c0327e30] [c0004b38] do_softirq+0x58/0x5c
>> [c0327e40] [c0023d90] irq_exit+0x98/0x9c
>> [c0327e50] [c0004dec] do_IRQ+0x9c/0xb4
>> [c0327e70] [c000e788] ret_from_except+0x0/0x14
>> [c0327f30] [c00440ac] tick_nohz_stop_sched_tick+0x404/0x4d0
>> [c0327f90] [c0007ac8] cpu_idle+0x50/0xe8
>> [c0327fb0] [c0002930] rest_init+0x5c/0x6c
>> [c0327fc0] [c02f088c] start_kernel+0x240/0x2c4
>> [c0327ff0] [c000222c] start_here+0x4c/0xb0
>> handlers:
>> [<c0193bc4>] (ata_sff_interrupt+0x0/0x208)
>> Disabling IRQ #26
>> IP-Config: Complete:
>>       device=eth0, addr=192.168.120.4, mask=255.255.0.0,
>> gw=192.168.1.254,
>>       host=kup4k, domain=, nis-domain=(none),
>>       bootserver=192.168.1.1, rootserver=192.168.1.1, rootpath=
>> ata2.00: CFA: TOSHIBA THNCF032MBA, 2.00, max PIO2
>> ata2.00: 63488 sectors, multi 0: LBA
>> ata2.00: configured for PIO2
>> ata2.00: configured for PIO2
>> ata2: EH complete
>> scsi 1:0:0:0: Direct-Access     ATA      TOSHIBA THNCF032 2.00 PQ: 0
>> ANSI: 5
>> sd 1:0:0:0: [sdb] 63488 512-byte logical blocks: (32.5 MB/31.0 MiB)
>> sd 1:0:0:0: [sdb] Write Protect is off
>> sd 1:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't
>> support DPO or FUA
>>   sdb: sdb1
>> sd 1:0:0:0: [sdb] Attached SCSI removable disk
>> Looking up port of RPC 100003/2 on 192.168.1.1
>> [...]
>>
>> -bash-3.2# cat /proc/interrupts
>>             CPU0
>>   17:          0   CPM PIC          Level        error
>>   18:          0   MPC8XX SIU       Level        tbint
>>   19:         59   CPM PIC          Level        cpm_uart
>>   21:          4   CPM PIC          Level        mpc8xxx_spi
>>   22:          0   MPC8XX SIU       Edge         ads7846
>>   23:      19950   MPC8XX SIU       Level        fs_enet-mac
>>   24:          0   MPC8XX SIU       Level        m8xx-pcmcia
>>   25:          9   MPC8XX SIU       Level        pata_pcmcia
>>   26:     100000   MPC8XX SIU       Level        pata_pcmcia
>>   27:         55   CPM PIC          Level        cpm_i2c
>> LOC:      15403   Local timer interrupts
>> SPU:          0   Spurious interrupts
>> CNT:          0   Performance monitoring interrupts
>> MCE:          0   Machine check exceptions
>> -bash-3.2#
>>
>> I found out, that this card raise an irq when
>> ata_dev_read_id() is called, and because
>> ata_dev_read_id() sets the ATA_TFLAG_POLLING flag,
>> the irq don;t get acked in ata_sff_interrupt()
>> (So the irq comes endless (100000 times before it
>>   get disabled))
> 
> Sounds like that card doesn't obey the nIEN flag to disable the
> interrupt, at least not on the identify command. Ugh.. Maybe we should
> be acking the interrupt anyway if we get one on a polling command? Not
> sure if that risks breaking anything or not..

Maybe the following patch is a better aproach, because it solves
my problem with a change only in the pata_pcmcia.c file:

ata, pcmcia: Work-around for interrupt-triggering IDENTIFY cmd.

In case the device does not honor nIEN when receiving the
IDENTIFY command, we disable polling mode, so that the
interrupt gets acknowledged nevertheless.

Suggested-by: Philippe Gerum <rpm@xenomai.org>
Signed-off-by: Heiko Schocher <hs@denx.de>
---
 drivers/ata/pata_pcmcia.c |   25 +++++++++++++++++++++++++
 1 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/drivers/ata/pata_pcmcia.c b/drivers/ata/pata_pcmcia.c
index 87fb4ad..91a9669 100644
--- a/drivers/ata/pata_pcmcia.c
+++ b/drivers/ata/pata_pcmcia.c
@@ -103,6 +103,30 @@ static int pcmcia_set_mode_8bit(struct ata_link *link,
 }

 /**
+ *	pcmcia_read_id - Work-around for interrupt-triggering IDENTIFY
+ *	command
+ *
+ *	In case the device does not honor nIEN when receiving the
+ *	IDENTIFY command, we disable polling mode, so that the
+ *	interrupt gets acknowledged nevertheless.
+ */
+
+static unsigned int pcmcia_read_id(struct ata_device *adev,
+				   struct ata_taskfile *tf, u16 *id)
+{
+	unsigned int err_mask;
+
+	/*
+	 * Maybe we should clear the flag conditionally, depending on the
+	 * device id?
+	 */
+	tf->flags &= ~ATA_TFLAG_POLLING;
+	err_mask = ata_do_dev_read_id(adev, tf, id);
+
+	return err_mask;
+}
+
+/**
  *	ata_data_xfer_8bit	 -	Transfer data by 8bit PIO
  *	@dev: device to target
  *	@buf: data buffer
@@ -172,6 +196,7 @@ static struct ata_port_operations pcmcia_port_ops = {
 	.sff_data_xfer	= ata_sff_data_xfer_noirq,
 	.cable_detect	= ata_cable_40wire,
 	.set_mode	= pcmcia_set_mode,
+	.read_id	= pcmcia_read_id,
 };

 static struct ata_port_operations pcmcia_8bit_port_ops = {
-- 
1.6.2.5


-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany