pxa2xx_spi suspend/resume

[Daniel Ribeiro <drwyrm-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Hello linux spi experts.

I'm trying to get suspend/resume working on my pxa27x board, but resume
freezes waiting for SPI I/O.

After correcting suspend/resume ordering (i need MCI and UDC to resume
after SPI, PMIC and USB transceiver on the SPI bus), it still freezes at
the first SPI transfer.

I added some debug code to pxa2xx_spi.c as follows:

@@ -1095,6 +1097,14 @@ static void pump_transfers(unsigned long data)
        /* after chip select, release the data by enabling service
         * requests and interrupts, without changing any mode bits */
        write_SSCR1(cr1, reg);
+       mdebug("pump_transfersA SSCR0=%08x SSCR1=%08x SSTO=%08x SSPSP=%08x SSSR=%08x\n",
+               read_SSCR0(drv_data->ioaddr), read_SSCR1(drv_data->ioaddr),
+               read_SSTO(drv_data->ioaddr), read_SSPSP(drv_data->ioaddr), read_SSSR(drv_data->ioaddr));
+       udelay(200);
+       mdebug("pump_transfersB SSCR0=%08x SSCR1=%08x SSTO=%08x SSPSP=%08x SSSR=%08x\n",
+               read_SSCR0(drv_data->ioaddr), read_SSCR1(drv_data->ioaddr),
+               read_SSTO(drv_data->ioaddr), read_SSPSP(drv_data->ioaddr), read_SSSR(drv_data->ioaddr));
+
 }
 
 static void pump_messages(struct work_struct *work)
@@ -1626,11 +1636,16 @@ static int pxa2xx_spi_suspend(struct platform_device *pdev, pm_message_t state)
        int status = 0;
 
        status = stop_queue(drv_data);
-       if (status != 0)
+       if (status != 0) {
+               mdebug("spi suspend: status error!\n");
                return status;
+       }
        write_SSCR0(0, drv_data->ioaddr);
        clk_disable(ssp->clk);
-
+       mdebug("spi suspend ok\n");
+       mdebug("SUSPEND SSCR0=%08x SSCR1=%08x SSTO=%08x SSPSP=%08x\n",
+               read_SSCR0(drv_data->ioaddr), read_SSCR1(drv_data->ioaddr),
+               read_SSTO(drv_data->ioaddr), read_SSPSP(drv_data->ioaddr));
        return 0;
 }
@@ -1649,6 +1665,9 @@ static int pxa2xx_spi_resume(struct platform_device *pdev)
                dev_err(&pdev->dev, "problem starting queue (%d)\n", status);
                return status;
        }
+       mdebug("RESUME SSCR0=%08x SSCR1=%08x SSTO=%08x SSPSP=%08x\n",
+               read_SSCR0(drv_data->ioaddr), read_SSCR1(drv_data->ioaddr),
+               read_SSTO(drv_data->ioaddr), read_SSPSP(drv_data->ioaddr));
 
        return 0;
 }

 
And this generates the following debug output:

I/O before suspend:
ezx_pcap_putget: W 9c0253d2
pump_transfersA SSCR0=0010008f SSCR1=00380740 SSTO=00000064 SSPSP=00000000 SSSR=0000f034
pump_transfersB SSCR0=0010008f SSCR1=00000740 SSTO=00000000 SSPSP=00000000 SSSR=0000f024
ezx_pcap_putget: R 000253d2

Suspend/Resume:
spi suspend ok
SUSPEND SSCR0=00000000 SSCR1=00000740 SSTO=00000000 SSPSP=00000000
RESUME SSCR0=00000000 SSCR1=00000740 SSTO=00000000 SSPSP=00000000

I/O after resume:
ezx_mci_setpower: 23
ezx_pcap_putget: W 1c000000
pump_transfersA SSCR0=0010008f SSCR1=00380740 SSTO=00000064 SSPSP=00000000 SSSR=0000f024
pump_transfersB SSCR0=0010008f SSCR1=00380740 SSTO=00000064 SSPSP=00000000 SSSR=0000f024


>From my limited knowledge on this, it looks like there is no SSP
peripheral clock after resume,  SSTO is not decremented after 200us.

Any pointer on how to fix this? Or other tests i should do?


-- 
Daniel Ribeiro


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