Subject: [PATCH 22/23] ARM: cci: driver need big endian fixes in asm code

From: [email-masked] (Ben Dooks)
Date: Mon, 14 Oct 2013 21:53:02 +0100

On 08/10/13 23:34, Ben Dooks wrote:
> From: Victor Kamensky<[email-masked]>
>
> cci_enable_port_for_self written in asm and it works with h/w
> registers that are in little endian format. When run in big
> endian mode it needs byte swap before/after it writes/reads
> to/from such registers
>
> CC: Lorenzon Pieralisi<[email-masked]>
> Signed-off-by: Victor Kamensky<[email-masked]>
> Signed-off-by: Ben Dooks<[email-masked]>
> ---
>   drivers/bus/arm-cci.c | 6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
> index 2009266..6db173e 100644
> --- a/drivers/bus/arm-cci.c
> +++ b/drivers/bus/arm-cci.c
> @@ -281,6 +281,9 @@ asmlinkage void __naked cci_enable_port_for_self(void)
>   	/* Enable the CCI port */
>   "	ldr	r0, [r0, %[offsetof_port_phys]] \n"
>   "	mov	r3, #"__stringify(CCI_ENABLE_REQ)" \n"
> +#ifdef __ARMEB__
> +"	rev	r3, r3 \n"
> +#endif /* __ARMEB__ */
>   "	str	r3, [r0, #"__stringify(CCI_PORT_CTRL)"] \n"
>
>   	/* poll the status reg for completion */
> @@ -288,6 +291,9 @@ asmlinkage void __naked cci_enable_port_for_self(void)
>   "	ldr	r0, [r1] \n"
>   "	ldr	r0, [r0, r1]		@ cci_ctrl_base \n"
>   "4:	ldr	r1, [r0, #"__stringify(CCI_CTRL_STATUS)"] \n"
> +#ifdef __ARMEB__
> +"	rev	r1, r1 \n"
> +#endif /* __ARMEB__ */
>   "	tst	r1, #1 \n"
>   "	bne	4b \n"

I was just thinking if this would be a better way to change
the code:

diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
index 6db173e..2ad2511 100644
--- a/drivers/bus/arm-cci.c
+++ b/drivers/bus/arm-cci.c
@@ -280,10 +280,7 @@ asmlinkage void __naked cci_enable_port_for_self(void)

         /* Enable the CCI port */
  "      ldr     r0, [r0, %[offsetof_port_phys]] \n"
-"      mov     r3, #"__stringify(CCI_ENABLE_REQ)" \n"
-#ifdef __ARMEB__
-"      rev     r3, r3 \n"
-#endif /* __ARMEB__ */
+"      mov     r3, %[cci_enable_req]\n"
  "      str     r3, [r0, #"__stringify(CCI_PORT_CTRL)"] \n"

         /* poll the status reg for completion */
@@ -291,10 +288,7 @@ asmlinkage void __naked cci_enable_port_for_self(void)
  "      ldr     r0, [r1] \n"
  "      ldr     r0, [r0, r1]            @ cci_ctrl_base \n"
  "4:    ldr     r1, [r0, #"__stringify(CCI_CTRL_STATUS)"] \n"
-#ifdef __ARMEB__
-"      rev     r1, r1 \n"
-#endif /* __ARMEB__ */
-"      tst     r1, #1 \n"
+"      tst     r1, %[cci_control_status_bits] \n"
  "      bne     4b \n"

  "      mov     r0, #0 \n"
@@ -307,6 +301,8 @@ asmlinkage void __naked cci_enable_port_for_self(void)
  "7:    .word   cci_ctrl_phys - . \n"
         : :
         [sizeof_cpu_port] "i" (sizeof(cpu_port)),
+       [cci_enable_req] "i" cpu_to_le32(CCI_ENABLE_REQ),
+       [cci_control_status_bits] "i" cpu_to_le32(1),

so swap the data bits before passing them into the code
which could also remove some of the use of the __stringify()
calls in there too.

It seems to compile ok, but is not complete.

-- 
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius