ARM: mach-omap2: clean up debug-macro.S

This achieves two goals:

1) Get rid of omap_uart_v2p() and omap_uart_p2v() which were the last users
   of PLAT_PHYS_OFFSET.

2) Remove the probing of the M bit in the CP15 control reg and make
   the access to the .data variables completely position independent.

There is a catch though: the busyuart macro needs to know where the LSR
register is which might be at a different offset depending on the hardware.
Given that this macro is given only two registers and that one of them
must be preserved, the trick is to always pass the LSR register address
around, and deduce the base address for the THR register by masking out
the LSR offset in senduart instead.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>

diff --git a/arch/arm/mach-omap2/include/mach/debug-macro.S b/arch/arm/mach-omap2/include/mach/debug-macro.S
index 745e2ff..13f98e5 100644 (file)
--- a/arch/arm/mach-omap2/include/mach/debug-macro.S
+++ b/arch/arm/mach-omap2/include/mach/debug-macro.S
@@ -13,15 +13,10 @@
 
 #include <linux/serial_reg.h>
 
-#include <asm/memory.h>
-
 #include <plat/serial.h>
 
 #define UART_OFFSET(addr)      ((addr) & 0x00ffffff)
 
-#define omap_uart_v2p(x)       ((x) - PAGE_OFFSET + PLAT_PHYS_OFFSET)
-#define omap_uart_p2v(x)       ((x) - PLAT_PHYS_OFFSET + PAGE_OFFSET)
-
                .pushsection .data
 omap_uart_phys:        .word   0
 omap_uart_virt:        .word   0
@@ -37,16 +32,16 @@ omap_uart_lsr:      .word   0
                .macro  addruart, rp, rv, tmp
 
                /* Use omap_uart_phys/virt if already configured */
-10:            mrc     p15, 0, \rp, c1, c0
-               tst     \rp, #1                 @ MMU enabled?
-               ldreq   \rp, =omap_uart_v2p(omap_uart_phys)     @ MMU disabled
-               ldrne   \rp, =omap_uart_phys    @ MMU enabled
-               add     \rv, \rp, #4            @ omap_uart_virt
-               ldr     \rp, [\rp, #0]
-               ldr     \rv, [\rv, #0]
+10:            adr     \rp, 99f                @ get effective addr of 99f
+               ldr     \rv, [\rp]              @ get absolute addr of 99f
+               sub     \rv, \rv, \rp           @ offset between the two
+               ldr     \rp, [\rp, #4]          @ abs addr of omap_uart_phys
+               sub     \tmp, \rp, \rv          @ make it effective
+               ldr     \rp, [\tmp, #0]         @ omap_uart_phys
+               ldr     \rv, [\tmp, #4]         @ omap_uart_virt
                cmp     \rp, #0                 @ is port configured?
                cmpne   \rv, #0
-               bne     99f                     @ already configured
+               bne     100f                    @ already configured
 
                /* Check the debug UART configuration set in uncompress.h */
                mov     \rp, pc
@@ -105,50 +100,47 @@ omap_uart_lsr:    .word   0
                b       98f
 83:            mov     \rp, #UART_OFFSET(TI816X_UART3_BASE)
                b       98f
+
 95:            ldr     \rp, =ZOOM_UART_BASE
-               mrc     p15, 0, \rv, c1, c0
-               tst     \rv, #1                 @ MMU enabled?
-               ldreq   \rv, =omap_uart_v2p(omap_uart_phys)     @ MMU disabled
-               ldrne   \rv, =omap_uart_phys    @ MMU enabled
-               str     \rp, [\rv, #0]
+               str     \rp, [\tmp, #0]         @ omap_uart_phys
                ldr     \rp, =ZOOM_UART_VIRT
-               add     \rv, \rv, #4            @ omap_uart_virt
-               str     \rp, [\rv, #0]
+               str     \rp, [\tmp, #4]         @ omap_uart_virt
                mov     \rp, #(UART_LSR << ZOOM_PORT_SHIFT)
-               add     \rv, \rv, #4            @ omap_uart_lsr
-               str     \rp, [\rv, #0]
+               str     \rp, [\tmp, #8]         @ omap_uart_lsr
                b       10b
 
                /* Store both phys and virt address for the uart */
 98:            add     \rp, \rp, #0x48000000   @ phys base
-               mrc     p15, 0, \rv, c1, c0
-               tst     \rv, #1                 @ MMU enabled?
-               ldreq   \rv, =omap_uart_v2p(omap_uart_phys)     @ MMU disabled
-               ldrne   \rv, =omap_uart_phys    @ MMU enabled
-               str     \rp, [\rv, #0]
+               str     \rp, [\tmp, #0]         @ omap_uart_phys
                sub     \rp, \rp, #0x48000000   @ phys base
                add     \rp, \rp, #0xfa000000   @ virt base
-               add     \rv, \rv, #4            @ omap_uart_virt
-               str     \rp, [\rv, #0]
+               str     \rp, [\tmp, #4]         @ omap_uart_virt
                mov     \rp, #(UART_LSR << OMAP_PORT_SHIFT)
-               add     \rv, \rv, #4            @ omap_uart_lsr
-               str     \rp, [\rv, #0]
+               str     \rp, [\tmp, #8]         @ omap_uart_lsr
 
                b       10b
-99:
+
+               .align
+99:            .word   .
+               .word   omap_uart_phys
+               .ltorg
+
+100:           /* Pass the UART_LSR reg address */
+               ldr     \tmp, [\tmp, #8]        @ omap_uart_lsr
+               add     \rp, \rp, \tmp
+               add     \rv, \rv, \tmp
                .endm
 
                .macro  senduart,rd,rx
-               strb    \rd, [\rx]
+               orr     \rd, \rd, \rx, lsl #24  @ preserve LSR reg offset
+               bic     \rx, \rx, #0xff         @ get base (THR) reg address
+               strb    \rd, [\rx]              @ send lower byte of rd
+               orr     \rx, \rx, \rd, lsr #24  @ restore original rx (LSR)
+               bic     \rd, \rd, #(0xff << 24) @ restore original rd
                .endm
 
                .macro  busyuart,rd,rx
-1001:          mrc     p15, 0, \rd, c1, c0
-               tst     \rd, #1                 @ MMU enabled?
-               ldreq   \rd, =omap_uart_v2p(omap_uart_lsr)      @ MMU disabled
-               ldrne   \rd, =omap_uart_lsr     @ MMU enabled
-               ldr     \rd, [\rd, #0]
-               ldrb    \rd, [\rx, \rd]
+1001:          ldrb    \rd, [\rx]              @ rx contains UART_LSR address
                and     \rd, \rd, #(UART_LSR_TEMT | UART_LSR_THRE)
                teq     \rd, #(UART_LSR_TEMT | UART_LSR_THRE)
                bne     1001b