Hello,
looking at CPU init during resume I noticed that the GPIOs settings is always executed (see for instance the first lines of file board/adsvix/lowlevel_init.S), but since PXA27x Developer's manual says at paragraph 3.8.1.9 that:
"These registers [PGSRx] are reset upon sleep or deep-sleep exit, so the configuration of the GPIO pins must be read from external memory. However, the GPIO state itself is not changed until software resets PSSR[PH].
we should setup, during resume, the GPIOs from Linux (or whatever OS we are using).
So the code:
lowlevel_init:
/* Set up GPIO pins first ----------------------------------------- */
ldr r0, =GPSR0 ldr r1, =CFG_GPSR0_VAL str r1, [r0]
ldr r0, =GPSR1 ldr r1, =CFG_GPSR1_VAL str r1, [r0]
ldr r0, =GPSR2 ldr r1, =CFG_GPSR2_VAL str r1, [r0]
ldr r0, =GPSR3 ldr r1, =CFG_GPSR3_VAL str r1, [r0]
ldr r0, =GPCR0 ldr r1, =CFG_GPCR0_VAL str r1, [r0]
ldr r0, =GPCR1 ldr r1, =CFG_GPCR1_VAL str r1, [r0]
ldr r0, =GPCR2 ldr r1, =CFG_GPCR2_VAL str r1, [r0]
ldr r0, =GPCR3 ldr r1, =CFG_GPCR3_VAL str r1, [r0]
ldr r0, =GPDR0 ldr r1, =CFG_GPDR0_VAL str r1, [r0]
ldr r0, =GPDR1 ldr r1, =CFG_GPDR1_VAL str r1, [r0]
ldr r0, =GPDR2 ldr r1, =CFG_GPDR2_VAL str r1, [r0]
ldr r0, =GPDR3 ldr r1, =CFG_GPDR3_VAL str r1, [r0]
ldr r0, =GAFR0_L ldr r1, =CFG_GAFR0_L_VAL str r1, [r0]
ldr r0, =GAFR0_U ldr r1, =CFG_GAFR0_U_VAL str r1, [r0]
ldr r0, =GAFR1_L ldr r1, =CFG_GAFR1_L_VAL str r1, [r0]
ldr r0, =GAFR1_U ldr r1, =CFG_GAFR1_U_VAL str r1, [r0]
ldr r0, =GAFR2_L ldr r1, =CFG_GAFR2_L_VAL str r1, [r0]
ldr r0, =GAFR2_U ldr r1, =CFG_GAFR2_U_VAL str r1, [r0]
ldr r0, =GAFR3_L ldr r1, =CFG_GAFR3_L_VAL str r1, [r0]
ldr r0, =GAFR3_U ldr r1, =CFG_GAFR3_U_VAL str r1, [r0]
ldr r0, =PSSR /* enable GPIO pins */ ldr r1, =CFG_PSSR_VAL str r1, [r0]
should be remove from per-board lowlevel_init.S and put into cpu/pxa/start.S after the lowlevel_init alling:
/* * before relocating, we have to setup RAM timing * because memory timing is board-dependend, you will * find a lowlevel_init.S in your board directory. */ mov ip, lr bl lowlevel_init mov lr, ip
<<HERE>>
or, at least, after the test:
wakeup: /* Are we waking from sleep? */ ldr r0, =RCSR ldr r1, [r0] and r1, r1, #(RCSR_GPR | RCSR_SMR | RCSR_WDR | RCSR_HWR) str r1, [r0] teq r1, #RCSR_SMR
in lowlevel_init.S.
Then the OS should manage the GPIOs resume at their old status before sleeping. In this manner we can get fully configurable GPIOs status setting during transition from suspend to resume.
Comments? :)
Ciao,
Rodolfo
P.S. Of course, if my supposition is correct I'll provide GPIOs resume in Linux too.
--
GNU/Linux Solutions e-mail: giometti@enneenne.com Linux Device Driver giometti@gnudd.com Embedded Systems giometti@linux.it UNIX programming phone: +39 349 2432127