[PATCH] ARM: mxc: ssi-fiq: Make ssi-fiq.S Thumb-2 compatible

On Mon, Aug 13, 2012 at 05:28:17PM -0500, Matt Sealey wrote:

 IMX_PIN_REG(MX51_PAD_EIM_DA15, NO_PAD, 0x058, 0, 0x000, 0), /*
MX51_PAD_EIM_DA15__EIM_DA15 */



On Mon, Aug 13, 2012 at 2:35 PM, Sascha Hauer [off-list ref] wrote:

quoted

Hi Dave,

On Fri, Aug 10, 2012 at 12:53:24PM +0100, Dave Martin wrote:

quoted

Because FIQ handlers get copied straight into the vectors page to
the FIQ vector entry point, FIQ handlers in a Thumb-2 kernel must
start in Thumb-2.  A Thumb-2 kernel enters all exception vectors in
Thumb-2.

I finally came along testing this. I have no Thumb2 capable hardware
to test if it works in thumb2 mode, but at least in Arm mode it works.
This is enough to not introduce a regression, so we can go for this.

This is the interesting dichotomy; the code is only required truly on
devices where Thumb2 isn't available, right?

It is also used on the i.MX51 Eukrea board. I asked Eric (Cced) to test
it in thumb2 mode, no response so far. I don't know the reason why he
uses FIQ mode instead of SDMA, maybe simply historical reasons.

Sascha

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