Hi Stephen,
On 24 November 2014 at 21:21, Stephen Warren swarren@nvidia.com wrote:
On 11/24/2014 08:58 AM, Simon Glass wrote:
Hi Stephen,
There was another thread where you reported a hang when booting Raspberry Pi with driver model. It can be repeated by applying this patch and trying to boot with syslinux.
http://patchwork.ozlabs.org/patch/392180/
When it hangs, the HDMI display displays lots of spaces, then lots of dots, scrolling forever. The serial console displays nothing further.
I narrowed the problem down to writing to address 0. So it is easy to repeat with something like 'mw 0 0'.
However I'm really not sure what is going on. Something with driver model seems to make address 0 sensitive to writes. I can't see what that might be, but I don't understand the platform very well. Do you have any ideas?
The problem seems to be that inside pl01x_serial_probe() (well, I assume all serial functions), dev_get_priv() returns 0, which ends up using address 0 as the UART address since that's the first field in struct pl01x_priv.
I found this by amending pl01x_serial_probe() as follows, and dumping the data after boot:
uint32_t *log = (uint32_t *)(128*1024*1024); uint32_t log_i = 1;
static int pl01x_serial_probe(struct udevice *dev) { struct pl01x_serial_platdata *plat = dev_get_platdata(dev); struct pl01x_priv *priv = dev_get_priv(dev);
log[log_i++] = (uint32_t)dev; log[log_i++] = (uint32_t)plat; log[log_i++] = (uint32_t)priv; log[0] = log_i; priv->regs = (struct pl01x_regs *)plat->base; priv->type = plat->type; return pl01x_generic_serial_init(priv->regs, priv->type);}
U-Boot> md.l 0x08000000 08000000: 00000007 07fffaf8 0003972c 00000000 ........,....... 08000010: 1db4e108 1df8372c 00000000 00000000 ....,7..........
It seems a bit odd that pl01x_serial_probe() is called twice, but perhaps that's expected?
Thanks for finding that! It just needs this in the U_BOOT_DRIVER() declaration in the serial driver:
.priv_auto_alloc_size = sizeof(struct pl01x_priv),
Then it all works. I'll update the series and resend. Thanks again.
Yes it will call the serial probe once before relocation, once after.
Regards, Simon