From de6b489ec52763ba1a6fa65a275c5f457f5d8238 Mon Sep 17 00:00:00 2001 From: Subrata Banik Date: Wed, 8 Dec 2021 16:23:39 +0530 Subject: mb/intel/adlrvp: Add support for external clock buffer ADL-P silicon can support 7 SRC CLK's and 10 CLKREQ signals. Out of 7 SRCCLK's 3 will be used for CPU, the rest are for PCH. If more than 4 PCH devices are connected on the platform, an external differential buffer chip needs to be placed at the platform level. A mainboard designer can choose to add an external clock chip, and select the SRC CLK using CONFIG_CLKSRC_FOR_EXTERNAL_BUFFER. CONFIG_CLKSRC_FOR_EXTERNAL_BUFFER provides the CLKSRC that feed clock to discrete buffer for further distribution to platform. TEST=Able to detect SD card connected at x4 PCIe Gen 3 Slot. localhost ~ # dmesg | grep mmc [ 4.997840] mmc0: SDHCI controller on PCI [0000:ae:00.0] using ADMA [ 5.460902] mmc0: new ultra high speed DDR50 SDHC card at address aaaa [ 5.473555] mmcblk0: mmc0:aaaa SS08G 7.40 GiB [ 5.494268] mmcblk0: p1 Change-Id: I21f1155374049c90aa45db25d4128b39aa5898bb Signed-off-by: Subrata Banik Reviewed-on: https://review.coreboot.org/c/coreboot/+/59976 Tested-by: build bot (Jenkins) Reviewed-by: Tim Wawrzynczak --- src/mainboard/intel/adlrvp/Kconfig | 18 ++++++++++++++++++ src/mainboard/intel/adlrvp/romstage_fsp_params.c | 21 +++++++++++++++++++++ 2 files changed, 39 insertions(+) (limited to 'src') diff --git a/src/mainboard/intel/adlrvp/Kconfig b/src/mainboard/intel/adlrvp/Kconfig index 657568502d..498fbc2a6e 100644 --- a/src/mainboard/intel/adlrvp/Kconfig +++ b/src/mainboard/intel/adlrvp/Kconfig @@ -23,12 +23,14 @@ config BOARD_INTEL_ADLRVP_P select DRIVERS_UART_8250IO select MAINBOARD_USES_IFD_EC_REGION select SOC_INTEL_ALDERLAKE_PCH_P + select GEN3_EXTERNAL_CLOCK_BUFFER config BOARD_INTEL_ADLRVP_P_EXT_EC select BOARD_INTEL_ADLRVP_COMMON select DRIVERS_INTEL_PMC select INTEL_LPSS_UART_FOR_CONSOLE select SOC_INTEL_ALDERLAKE_PCH_P + select GEN3_EXTERNAL_CLOCK_BUFFER config BOARD_INTEL_ADLRVP_P_MCHP select BOARD_INTEL_ADLRVP_COMMON @@ -140,4 +142,20 @@ config DRIVER_TPM_SPI_BUS config TPM_TIS_ACPI_INTERRUPT int default 67 if BOARD_INTEL_ADLRVP_M_EXT_EC # GPE0_DW2_3 (GPP_E3) + +config GEN3_EXTERNAL_CLOCK_BUFFER + bool + depends on SOC_INTEL_ALDERLAKE_PCH_P + default n + help + Support external Gen-3 clock chip for ADL-P. + `CONFIG_CLKSRC_FOR_EXTERNAL_BUFFER` provides feed clock to discrete buffer + for further distribution to platform. SRCCLKREQB[7:9] maps to internal + SRCCLKREQB[6]. If any of them asserted, SRC buffer + `CONFIG_CLKSRC_FOR_EXTERNAL_BUFFER` gets enabled. + +config CLKSRC_FOR_EXTERNAL_BUFFER + depends on GEN3_EXTERNAL_CLOCK_BUFFER + int + default 6 # CLKSRC 6 endif diff --git a/src/mainboard/intel/adlrvp/romstage_fsp_params.c b/src/mainboard/intel/adlrvp/romstage_fsp_params.c index 34fc04e6cb..05d2a173ff 100644 --- a/src/mainboard/intel/adlrvp/romstage_fsp_params.c +++ b/src/mainboard/intel/adlrvp/romstage_fsp_params.c @@ -24,6 +24,24 @@ static size_t get_spd_index(void) return spd_index; } +/* + * ADL-P silicon can support 7 SRC CLK's and 10 CLKREQ signals. Out of 7 SRCCLK's + * 3 will be used for CPU, the rest are for PCH. If more than 4 PCH devices are + * connected on the platform, an external differential buffer chip needs to be placed at + * the platform level. + * + * GEN3_EXTERNAL_CLOCK_BUFFER Kconfig is selected for ADL-P RVP (not applicable for + * ADL-M/N RVP) + * + * CONFIG_CLKSRC_FOR_EXTERNAL_BUFFER provides the CLKSRC that feed clock to discrete + * buffer for further distribution to platform. + */ +static void configure_external_clksrc(FSP_M_CONFIG *m_cfg) +{ + for (unsigned int i = CONFIG_MAX_PCIE_CLOCK_SRC; i < CONFIG_MAX_PCIE_CLOCK_REQ; i++) + m_cfg->PcieClkSrcUsage[i] = CONFIG_CLKSRC_FOR_EXTERNAL_BUFFER; +} + void mainboard_memory_init_params(FSP_M_CONFIG *m_cfg) { const struct mb_cfg *mem_config = variant_memory_params(); @@ -68,4 +86,7 @@ void mainboard_memory_init_params(FSP_M_CONFIG *m_cfg) die("Unknown board id = 0x%x\n", board_id); break; } + + if (CONFIG(GEN3_EXTERNAL_CLOCK_BUFFER)) + configure_external_clksrc(m_cfg); } -- cgit v1.2.3