Matt DeVillier (matt.devillier@gmail.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/18309
-gerrit
commit 605af7eedfa556d180da59578aac1a819933cd10 Author: Matt DeVillier matt.devillier@gmail.com Date: Tue Feb 7 22:07:56 2017 -0600
google/rambi: add explicit pull-down for ram-id
Some variants need the internal pull resistor on GPIO_SSUS_40 set explicitly to pull down rather than disabling the pull, in order for the ram-id to be read correctly via GPIO.
Correct this by adding a function to enable and set the internal pull (taken from Chromium) and define its use as needed in the board's variant.h.
Test: boot 4GB Candy board and observe correct RAM amount detected
Change-Id: I8823c27385f4422184b5afa57f6048f7ff2a25ab Signed-off-by: Matt DeVillier matt.devillier@gmail.com --- src/mainboard/google/rambi/romstage.c | 5 ++++- .../google/rambi/variants/candy/include/variant/variant.h | 1 + .../google/rambi/variants/glimmer/include/variant/variant.h | 1 + .../google/rambi/variants/gnawty/include/variant/variant.h | 2 ++ src/soc/intel/baytrail/include/soc/gpio.h | 7 +++++++ 5 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/src/mainboard/google/rambi/romstage.c b/src/mainboard/google/rambi/romstage.c index d8ba001..25fe859 100644 --- a/src/mainboard/google/rambi/romstage.c +++ b/src/mainboard/google/rambi/romstage.c @@ -32,7 +32,10 @@ static void *get_spd_pointer(char *spd_file_content, int total_spds, int *dual) ssus_disable_internal_pull(GPIO_SSUS_37_PAD); ssus_disable_internal_pull(GPIO_SSUS_38_PAD); ssus_disable_internal_pull(GPIO_SSUS_39_PAD); -#ifdef GPIO_SSUS_40_PAD +#ifdef GPIO_SSUS_40_PAD_USE_PULLDOWN + /* To prevent floating pin on shipped systems. */ + ssus_enable_internal_pull(GPIO_SSUS_40_PAD, PAD_PULL_DOWN | PAD_PU_20K); +#elif defined (GPIO_SSUS_40_PAD) ssus_disable_internal_pull(GPIO_SSUS_40_PAD); #endif ram_id |= (ssus_get_gpio(GPIO_SSUS_37_PAD) << 0); diff --git a/src/mainboard/google/rambi/variants/candy/include/variant/variant.h b/src/mainboard/google/rambi/variants/candy/include/variant/variant.h index 0c58cee..fe4c475 100644 --- a/src/mainboard/google/rambi/variants/candy/include/variant/variant.h +++ b/src/mainboard/google/rambi/variants/candy/include/variant/variant.h @@ -38,5 +38,6 @@ static const uint32_t dual_channel_config = #define GPIO_SSUS_38_PAD 50 #define GPIO_SSUS_39_PAD 58 #define GPIO_SSUS_40_PAD 52 +#define GPIO_SSUS_40_PAD_USE_PULLDOWN
#endif diff --git a/src/mainboard/google/rambi/variants/glimmer/include/variant/variant.h b/src/mainboard/google/rambi/variants/glimmer/include/variant/variant.h index 0ea42c5..59d5ee1 100644 --- a/src/mainboard/google/rambi/variants/glimmer/include/variant/variant.h +++ b/src/mainboard/google/rambi/variants/glimmer/include/variant/variant.h @@ -38,5 +38,6 @@ static const uint32_t dual_channel_config = #define GPIO_SSUS_38_PAD 50 #define GPIO_SSUS_39_PAD 58 #define GPIO_SSUS_40_PAD 52 +#define GPIO_SSUS_40_PAD_USE_PULLDOWN
#endif diff --git a/src/mainboard/google/rambi/variants/gnawty/include/variant/variant.h b/src/mainboard/google/rambi/variants/gnawty/include/variant/variant.h index 9bac7bc..bd79c98 100644 --- a/src/mainboard/google/rambi/variants/gnawty/include/variant/variant.h +++ b/src/mainboard/google/rambi/variants/gnawty/include/variant/variant.h @@ -33,5 +33,7 @@ static const uint32_t dual_channel_config = #define GPIO_SSUS_37_PAD 57 #define GPIO_SSUS_38_PAD 50 #define GPIO_SSUS_39_PAD 58 +#define GPIO_SSUS_40_PAD 52 +#define GPIO_SSUS_40_PAD_USE_PULLDOWN
#endif diff --git a/src/soc/intel/baytrail/include/soc/gpio.h b/src/soc/intel/baytrail/include/soc/gpio.h index 3757eb0..9c6b7fd 100644 --- a/src/soc/intel/baytrail/include/soc/gpio.h +++ b/src/soc/intel/baytrail/include/soc/gpio.h @@ -454,4 +454,11 @@ static inline void ssus_disable_internal_pull(int pad) write32(ssus_pconf0(pad), read32(ssus_pconf0(pad)) & pull_mask); }
+static inline void ssus_enable_internal_pull(int pad, int mask) +{ + const int pull_mask = ~(0xf << 7); + write32(ssus_pconf0(pad), + (read32(ssus_pconf0(pad)) & pull_mask) | mask); +} + #endif /* _BAYTRAIL_GPIO_H_ */
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Matt DeVillier