sun6i: Add defconfig for MSI Primo81 tablet

This patch uses the same ZQ and DRAM clock settings as in the
pre-installed Android firmware.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sun7i: Add defconfig for MSI Primo73 tablet

This patch uses the same DRAM settings as in the pre-installed
Android firmware. The LCD display is supported too.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: Fix buggy sun6i/sun8i DRAM size detection logic

After reboot, reset or even short power off, DRAM typically retains
the old stale data for some period of time (for this type of memory,
the bits of data are stored in slowly discharging capacitors).

The current sun6i/sun8i DRAM size detection logic, which is
inherited from the Allwinner code, relies on using a large magic
signature with the hope that it is unique enough and unlikely to
ever accidentally match this leftover garbage data in RAM. But
this approach is inherently unsafe, as can be demonstrated using
the following test program:

/***** A testcase for reproducing the problem ******/

void main(int argc, char *argv[])
{
    size_t size, i;
    uint32_t *buf;
    /* Allocate the buffer */
    if (argc < 2 || !(size = (size_t)atoi(argv[1]) * 1048576) ||
                    !(buf = malloc(size))) {
        printf("Need buffer size in MiB as a cmdline argument\n");
        exit(1);
    }
    /* Fill it with the Allwinner DRAM "magic" values */
    for (i = 0; i < size / 4; i++)
        buf[i] = 0xaa55aa55 + ((uintptr_t)&buf[i] / 4) % 64;
    /* Try to reboot */
    system("reboot");
    /* And wait */
    for (;;) {}
}
/***************************************************/

If this test program is run on the device (giving it a large
chunk of memory), then the DRAM size detection logic in u-boot
gets confused after reboot and fails to initialize DRAM properly.

A better approach is not to rely on luck and abstain from making
any assumptions about the properties of the leftover garbage
data in RAM. Instead just use a more reliable code for testing
whether two different addresses refer to the same memory location.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: Fix PLL1 running at half speed on sun8i

PLL1 on sun6i / sun8i also has a p factor which divides the clock by
2^p (to the power p). On sun6i the p factor is ignored, but on sun8i it is
used and we were setting it to 1, resulting in the CPU running at 504 MHz
instead of 1008 MHz, this commit fixes this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>