On 12/14/2015 07:03 PM, Gong Qianyu-B52263 wrote:
-----Original Message----- From: Sun York-R58495 Sent: Monday, December 14, 2015 6:37 PM To: Gong Qianyu-B52263; u-boot@lists.denx.de Cc: Hu Mingkai-B21284; Sun York-R58495; Fan Peng-B51431 Subject: Re: [PATCH] i2c: mxc: allow executing the code that only applies to i.MX platforms
On 12/14/2015 06:23 PM, Gong Qianyu wrote: The bus_i2c_init() is called before relocation and will assgin value to a static variable. If U-Boot is then still running in a flash device, it's theoretically not allowed to write data to flash without an erasing operation. For i.MX platforms, the U-Boot is always running in DDR.
Actually it causes asynchronous error when the ARM64 system error report is enabled and the flash write protect is set.
Signed-off-by: Gong Qianyu Qianyu.Gong@freescale.com
drivers/i2c/mxc_i2c.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c index fa4c82f..4dddb83 100644 --- a/drivers/i2c/mxc_i2c.c +++ b/drivers/i2c/mxc_i2c.c @@ -581,8 +581,11 @@ void bus_i2c_init(int index, int speed, int unused, return; }
+#if defined(CONFIG_MX51) || defined(CONFIG_MX53) || \
- defined(CONFIG_MX6) || defined(CONFIG_MX7) mxc_i2c_buses[index].idle_bus_fn = idle_bus_fn; mxc_i2c_buses[index].idle_bus_data = idle_bus_data;
+#endif
I also think using variable mxc_i2c_buses is problematic. But using ifdef doesn't look like a solution. I think this variable should be put into stack, or use malloc. It works with execution-in-place in read-only space.
York
But we don't know if the stack will be enough before relocation. For SD boot of LS1043A,
there is now only 4KB for it and if the spl image is bigger in the future, the stack is
smaller. So isn't leaving more stack(if possible) for necessary code better?
This array is small. The size of stack depends on the deepest one in all functions. I don't think this driver use deep stack. I remember Linux has a tool to calculate the stack. You can try it to examine the stack depth.
York
Ok. So the array won't need to be reserved in stack. I just didn't read much of the driver code and wanted to keep the original meaning of the author. I'm also confused why it has to be static. But before that it was put in gdata.
Regards, Qianyu