soc/intel/skylake:Add _DSM method to reduce D3 cold delay for eMMC controller

eMMC Controller is taking over 100ms to resume during runtime which
results in I/O latency issues on the Skylake systems like Cave and Caroline.

This patch adds _DSM method for eMMC comtroller for specifying the
device readiness durations. Function index 9 returns package of five
integers to set D3 cold delay to zero and ACPI constant Ones for the
elements where overriding the default values is not desired.

BUG=b:35774937
BRANCH=none
TEST=update caroline coreboot and test i/o latency is under 100ms

Change-Id: Iacc8aa8560897da8770fe559ca8cd17aaf6ebeba
Signed-off-by: Sowmya V <v.sowmya@intel.com>
Reviewed-on: https://review.coreboot.org/18532
Tested-by: build bot (Jenkins)
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
This commit is contained in:
sowmyav 2017-03-02 10:09:59 +05:30 committed by Martin Roth
parent 6e53ae6f5c
commit d448a5e98b
1 changed files with 43 additions and 0 deletions

View File

@ -20,6 +20,7 @@ Device (EMMC)
{
Name (_ADR, 0x001E0004)
Name (_DDN, "eMMC Controller")
Name (UUID, ToUUID ("E5C937D0-3553-4D7A-9117-EA4D19C3434D"))
OperationRegion (EMCR, PCI_Config, 0x00, 0x100)
Field (EMCR, DWordAcc, NoLock, Preserve)
@ -31,6 +32,48 @@ Device (EMMC)
PGEN, 1, /* PG_ENABLE */
}
/*
* Device Specific Method
* Arg0 - UUID
* Arg1 - Revision
* Arg2 - Function Index
*/
Method (_DSM, 4)
{
If (LEqual (Arg0, ^UUID)) {
/*
* Function 9: Device Readiness Durations
* Returns a package of five integers covering
* various device related delay in PCIe Base Spec.
*/
If (LEqual (Arg2, 9)) {
/*
* Function 9 support for revision 3.
* ECN link for function definitions
* [https://pcisig.com/sites/default/files/
* specification_documents/
* ECN_fw_latency_optimization_final.pdf]
*/
If (LEqual (Arg1, 3)) {
/*
* Integer 0: FW reset time.
* Integer 1: FW data link up time.
* Integer 2: FW functional level reset
* time.
* Integer 3: FW D3 hot to D0 time.
* Integer 4: FW VF enable time.
* set ACPI constant Ones for elements
* where overriding the default value
* is not desired.
*/
Return (Package (5) {0, Ones, Ones,
Ones, Ones})
}
}
}
Return (Buffer() { 0x00 })
}
Method (_PS0, 0, Serialized)
{
/* Disable Power Gate */