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soc/intel/common: Refine pmc_get_xtal_freq function 

1. Remove 'PCH_EPOC_XTAL_FREQ(__epoc)' macro since it only be used
   in 1 place.

2. Transform macro into more readable C code.

3. Add additional case check to make sure the returned value is
   defined in the 'pch_pmc_xtal' enum.

Signed-off-by: Lean Sheng Tan <lean.sheng.tan@intel.com>
Change-Id: If57a99bf8e837a6eb8f225297399b1f5363cfa85
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55587
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
This commit is contained in:
Lean Sheng Tan 2021-06-16 09:41:37 -07:00 committed by Werner Zeh
parent 508dc163f1
commit bed1b602d0
2 changed files with 19 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/soc/intel/common/block/include/intelblocks/pmclib.h
View File

@ -7,19 +7,19 @@
#include <types.h>
#define PCH_PMC_EPOC 0x18EC
/* XTAL frequency in bits 21, 20, 17 */
#define PCH_EPOC_XTAL_FREQ(__epoc) ((((__epoc) >> 19) & 0x6) | ((__epoc) >> 17 & 0x1))
/**
* enum pch_pmc_xtal - External crystal oscillator frequency.
* @XTAL_24_MHZ: 24 MHz external crystal.
* @XTAL_19_2_MHZ: 19.2 MHz external crystal.
* @XTAL_38_4_MHZ: 38.4 MHz external crystal.
* @XTAL_UNKNOWN_FREQ: Unsupported external crystal.
*/
enum pch_pmc_xtal {
XTAL_24_MHZ,
XTAL_19_2_MHZ,
XTAL_38_4_MHZ,
XTAL_UNKNOWN_FREQ = 0xf,
};
/*

19
src/soc/intel/common/block/pmc/pmclib.c
View File

@ -732,7 +732,22 @@ enum pch_pmc_xtal pmc_get_xtal_freq(void)
if (!CONFIG(PMC_EPOC))
dead_code();
const uintptr_t pmcbase = soc_read_pmc_base();
uint32_t xtal_freq = 0;
const uint32_t epoc = read32p(soc_read_pmc_base() + PCH_PMC_EPOC);
return PCH_EPOC_XTAL_FREQ(read32((uint32_t *)(pmcbase + PCH_PMC_EPOC)));
/* XTAL frequency in bits 21, 20, 17 */
xtal_freq |= !!(epoc & (1 << 21)) << 2;
xtal_freq |= !!(epoc & (1 << 20)) << 1;
xtal_freq |= !!(epoc & (1 << 17)) << 0;
switch (xtal_freq) {
case 0:
return XTAL_24_MHZ;
case 1:
return XTAL_19_2_MHZ;
case 2:
return XTAL_38_4_MHZ;
default:
printk(BIOS_ERR, "Unknown EPOC XTAL frequency setting %u\n", xtal_freq);
return XTAL_UNKNOWN_FREQ;
}
}