On Fri, Jun 22, 2018 at 11:37:30PM +0200, BALATON Zoltan wrote: > > >>The version of the Linux kernel I've tried (which is from the Linux CD > >>on ACube's site) did not try to access the power management register, > >>neither any guest OSes I've tested with. Looks like it may be specific > >>to the kernel config you're using. > >> > >Interesting. This is with the standard upstream kernel, using > >canyonlands_defconfig. > >The code seems to have been in the upstream kernel forever. > > Maybe the Sam460ex specific image has some patches not in upstream kernel. >
Yes, it does. To start with, the DesignWare sata driver is different. This is not the reason for the problem, though. canyonlands_defconfig in the upstream kernel has CONFIG_SUSPEND enabled, but the configuration used by aCube doesn't. The kernel code accessing the power management registers is only enabled with CONFIG_SUSPEND. > >>By the way, when I've tried with a more recent Linux kernel (4.15.10) > >>I've noticed that the sm501 driver seemed like having endianness > >>problems and thus did not find the chip, while it works with other older > >>kernels made for sam460ex. I did not try to debug or bisect this yet. Do > >>you know anything about that? > >> > > > >No, I had not noticed. SM501 is disabled in the latest canyonlands_defconfig, > >and I only use the serial console for my testing. It fails as far back as > >3.18.y, > >so I am not sure if this is a Linux or a qemu problem, or if it is a > >problem that > >was never fixed in the upstream kernel. What kernels did you try ? > The problem is this (from the kernel diffs provided by aCube): #if defined(CONFIG_PPC32) -#define smc501_readl(addr) ioread32be((addr)) -#define smc501_writel(val, addr) iowrite32be((val), (addr)) +#define smc501_readl(addr) ioread32((addr)) +#define smc501_writel(val, addr) iowrite32((val), (addr)) #else #define smc501_readl(addr) readl(addr) #define smc501_writel(val, addr) writel(val, addr) This is a bit fishy since the cpu is big endian and iowrite32be() should be identical to iowrite32(), but apparently that is not the case here. I don't think I'll have time to track this down, though. Guenter
