Re: [Qemu-devel] [PATCH v4 3/3] i.MX: Add an i.MX25 specific CCM class/instance.

[Peter Crosthwaite]

On Wed, Nov 25, 2015 at 11:16 PM, Jean-Christophe Dubois
<address@hidden> wrote:
> Signed-off-by: Jean-Christophe Dubois <address@hidden>

This seems to slow down boot performance for i.MX25 Linux. Admittedly,
the issue looks to be in timeout code for an unmodelled periph (NAND):

------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at
/home/pcrost/poky/build/tmp/work-shared/qemuarmv5imx/kernel-source/drivers/mtd/nand/mxc_nand.c:464
wait_op_done+0xf0/0x114()
timeout! useirq=0
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 4.2.1 #1
Hardware name: Freescale i.MX25 (Device Tree Support)
[<c000eec8>] (unwind_backtrace) from [<c000d2b0>] (show_stack+0x10/0x14)
[<c000d2b0>] (show_stack) from [<c0019154>] (warn_slowpath_common+0x74/0xac)
[<c0019154>] (warn_slowpath_common) from [<c00191bc>]
(warn_slowpath_fmt+0x30/0x40)
[<c00191bc>] (warn_slowpath_fmt) from [<c036eaa0>] (wait_op_done+0xf0/0x114)
[<c036eaa0>] (wait_op_done) from [<c0369698>] (nand_scan_ident+0xdc/0x1560)
[<c0369698>] (nand_scan_ident) from [<c036e6a8>] (mxcnd_probe+0x378/0x5c0)
[<c036e6a8>] (mxcnd_probe) from [<c03081a4>] (platform_drv_probe+0x44/0xac)
[<c03081a4>] (platform_drv_probe) from [<c0306654>]
(driver_probe_device+0x180/0x2c4)
[<c0306654>] (driver_probe_device) from [<c0306824>] (__driver_attach+0x8c/0x90)
[<c0306824>] (__driver_attach) from [<c0304a80>] (bus_for_each_dev+0x70/0xa0)
[<c0304a80>] (bus_for_each_dev) from [<c0305d08>] (bus_add_driver+0x188/0x210)
[<c0305d08>] (bus_add_driver) from [<c03071d4>] (driver_register+0x78/0xf8)
[<c03071d4>] (driver_register) from [<c00095e0>] (do_one_initcall+0x84/0x1f0)
[<c00095e0>] (do_one_initcall) from [<c071bd24>]
(kernel_init_freeable+0x108/0x1c8)
[<c071bd24>] (kernel_init_freeable) from [<c0541a0c>] (kernel_init+0x8/0xec)
[<c0541a0c>] (kernel_init) from [<c000a340>] (ret_from_fork+0x14/0x34)
---[ end trace 13248cb1a1bbcb9c ]---

<<Delay happens here>>

nand: No NAND device found
...

Without this patch, the delay is around 2 seconds, with this patch it
is 10+. Any idea what would cause it? Are you removing the NAND from
DTS for your testing and do we not care about these errors paths?

Regards,
Peter


> ---
>
> Changes since v1:
>  * rework loging to match other i.MX drivers
>
> Changes since v2:
>  * We moved to an inheritance QOM scheme
>
> Changes since v3:
>  * Rework logging based on comments.
>
>  hw/arm/fsl-imx25.c          |   2 +-
>  hw/misc/Makefile.objs       |   1 +
>  hw/misc/imx25_ccm.c         | 276 
> ++++++++++++++++++++++++++++++++++++++++++++
>  include/hw/arm/fsl-imx25.h  |   4 +-
>  include/hw/misc/imx25_ccm.h |  59 ++++++++++
>  5 files changed, 339 insertions(+), 3 deletions(-)
>  create mode 100644 hw/misc/imx25_ccm.c
>  create mode 100644 include/hw/misc/imx25_ccm.h
>