AMD Fam14 boards: Set P_BLK length to 6 for all processors

Currently on for example on AMD Persimmon and ASRock E350M1 Linux
complains, that the PBLK length is invalid [1].

        ACPI: Invalid PBLK length [0]

Consequently, frequency scaling might not work correctly, though for
these two boards it seems to work according to PowerTOP.

Indeed, according to the ACPI specification [2], setting PBlockLength
to 0 is only allowed if there is no PBlockAddress. Otherwise it has to
be set to 6.

        18.5.93 Processor (Declare Processor)

        […]

        PBlockAddress provides the system I/O address for the processors
        register block. Each processor can supply a different such
        address. PBlockLength is the length of the processor register
        block, in bytes and is either 0 (for no P_BLK) or 6. With one
        exception, all processors are required to have the same
        PBlockLength. The exception is that the boot processor can have
        a non-zero PBlockLength when all other processors have a zero
        PBlockLength. It is valid for every processor to have a
        PBlockLength of 0.

And that is exactly what Linux is checking in
`drivers/acpi/processor_driver.c` [3].

        static int acpi_processor_get_info(struct acpi_device *device)
        {
        […]
                /*
                 * On some boxes several processors use the same processor bus id.
                 * But they are located in different scope. For example:
                 * \_SB.SCK0.CPU0
                 * \_SB.SCK1.CPU0
                 * Rename the processor device bus id. And the new bus id will be
                 * generated as the following format:
                 * CPU+CPU ID.
                 */
                sprintf(acpi_device_bid(device), "CPU%X", pr->id);
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Processor [%d:%d]\n", pr->id,
                                  pr->acpi_id));

                if (!object.processor.pblk_address)
                        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No PBLK (NULL address)\n"));
                else if (object.processor.pblk_length != 6)
                        printk(KERN_ERR PREFIX "Invalid PBLK length [%d]\n",
                                    object.processor.pblk_length);
                else {
                        pr->throttling.address = object.processor.pblk_address;
                        pr->throttling.duty_offset = acpi_gbl_FADT.duty_offset;
                        pr->throttling.duty_width = acpi_gbl_FADT.duty_width;

                        pr->pblk = object.processor.pblk_address;

                        /*
                         * We don't care about error returns - we just try to mark
                         * these reserved so that nobody else is confused into thinking
                         * that this region might be unused..
                         *
                         * (In particular, allocating the IO range for Cardbus)
                         */
                        request_region(pr->throttling.address, 6, "ACPI CPU throttle");
                }
        […]
        }

This issue has proliferated to all AMD based boards so fix it for
all of them by setting P_BLK length to 6.

The DSDT of for example AMD Parmer and AMD Thatcher also set it
to 6 everywhere so this solution is taken instead of setting the
P_BLK system I/O base to 0 for all but the first processor which
is how it is done for earlier AMD based boards.

As note having to set this manually should not be needed and
this should be autogenerated as done for most of the Intel boards
and the AMD K8 based boards (`src/cpu/amd/model_fxx/powernow_acpi.c`).

[1] http://www.coreboot.org/pipermail/coreboot/2013-January/073636.html
[2] http://acpi.info/DOWNLOADS/ACPIspec40a.pdf
[3] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=drivers/acpi/processor_driver.c;h=e83311bf1ebdaaaea1adbf2de1351cca907d3465;hb=5da1f88b8b727dc3a66c52d4513e871be6d43d19#l351

Tested-by: Paul Menzel <paulepanter@users.sourceforge.net>
• ASRock E350M1:
Tested-by: Paul Menzel <paulepanter@users.sourceforge.net>
• AMD Persimmon:
Tested-by: Martin Roth <martin.roth@se-eng.com>
Change-Id: Ie79fe4812532d124cc81747c75a4f3d88d00531c
Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-on: http://review.coreboot.org/2189
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martin.roth@se-eng.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/mainboard/amd/persimmon/dsdt.asl b/src/mainboard/amd/persimmon/dsdt.asl
index c7b44d05ad..624919acdb 100644
--- a/src/mainboard/amd/persimmon/dsdt.asl
+++ b/src/mainboard/amd/persimmon/dsdt.asl
@@ -75,21 +75,21 @@ DefinitionBlock (
 			C001,		/* name space name */
 			1,		/* Unique number for this processor */
 			0x810,		/* PBLK system I/O address !hardcoded! */
-			0x00		/* PBLKLEN for boot processor */
+			0x06		/* PBLKLEN for boot processor */
 			) {
 		}
 		Processor(
 			C002,		/* name space name */
 			2,		/* Unique number for this processor */
 			0x810,		/* PBLK system I/O address !hardcoded! */
-			0x00		/* PBLKLEN for boot processor */
+			0x06		/* PBLKLEN for boot processor */
 			) {
 		}
 		Processor(
 			C003,		/* name space name */
 			3,		/* Unique number for this processor */
 			0x810,		/* PBLK system I/O address !hardcoded! */
-			0x00		/* PBLKLEN for boot processor */
+			0x06		/* PBLKLEN for boot processor */
 			) {
 		}
 	} /* End _PR scope */