On Thu, 2017-04-06 at 10:38 +0200, Greg Kroah-Hartman wrote: > 4.4-stable review patch. If anyone has any objections, please let me know. > > ------------------ > > From: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx> > > commit 0b0408745e7ff24757cbfd571d69026c0ddb803c upstream. > > LPDDR memories can only handle up to 400 uncontrolled power off. Ensure the > proper power off sequence is used before shutting down the platform. > > Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Sebastian Reichel <sre@xxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> [...] > +static void at91_lpddr_poweroff(void) > +{ > + asm volatile( > + /* Align to cache lines */ > + ".balign 32\n\t" > + > + /* Ensure AT91_SHDW_CR is in the TLB by reading it */ > + " ldr r6, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t" This clobbers r6... > + /* Power down SDRAM0 */ > + " str %1, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t" > + /* Shutdown CPU */ > + " str %3, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t" > + > + " b .\n\t" > + : > + : "r" (mpddrc_base), > + "r" cpu_to_le32(AT91_DDRSDRC_LPDDR2_PWOFF), > + "r" (at91_shdwc_base), > + "r" cpu_to_le32(AT91_SHDW_KEY | AT91_SHDW_SHDW) > + : "r0"); [...] ...but the clobber list has r0. Ben. -- Ben Hutchings Software Developer, Codethink Ltd.