From: Roger Quadros rogerq@ti.com

NB0 is bridge to SRAM and NB1 is bridge to DDR.

To ensure that SRAM transfers are not stalled due to delays during DDR refreshes, SRAM traffic should be higher priority (threadmap=2) than DDR traffic (threadmap=0).

This fixup is critical to provide deterministic access latency to MSMC from ICSSG, it applies to all AM65 silicon revisions and is due to incorrect reset values (has no erratum id) and statically setting things up should be done independent of usecases and board.

This specific style of Northbridge configuration is specific only to AM65x devices, follow-on K3 devices have different data prioritization schemes (ASEL and the like) and hence the fixup applies purely to AM65x.

Without this fix, ICSSG TX lock-ups due to delays in MSMC transfers in case of SR1 devices, on SR2 devices, lockups were not observed so far but high retry rates of ICSSG Ethernet (icssg-eth) and, thus, lower throughput.

Signed-off-by: Roger Quadros rogerq@ti.com Acked-by: Andrew F. Davis afd@ti.com Acked-by: Tomi Valkeinen tomi.valkeinen@ti.com Acked-by: Benoit Parrot bparrot@ti.com [Jan: rebased, dropped used define, extended commit log] Signed-off-by: Jan Kiszka jan.kiszka@siemens.com [Nishanth: Provide relevant context in the commit message] Signed-off-by: Nishanth Menonnm@ti.com ---

Changes in V2: * rebase (Thanks Jan) * Updated commit message.

V1: https://patchwork.ozlabs.org/project/uboot/patch/20200130080503.28657-1-roge...

arch/arm/mach-k3/am6_init.c | 15 +++++++++++++++ arch/arm/mach-k3/include/mach/am6_hardware.h | 6 ++++++ 2 files changed, 21 insertions(+)

diff --git a/arch/arm/mach-k3/am6_init.c b/arch/arm/mach-k3/am6_init.c index 425b3f93c865..ffb7aaded2e7 100644 --- a/arch/arm/mach-k3/am6_init.c +++ b/arch/arm/mach-k3/am6_init.c @@ -151,6 +151,19 @@ int fdtdec_board_setup(const void *fdt_blob) return fixup_usb_boot(); } #endif + +static void setup_am654_navss_northbridge(void) +{ + /* + * NB0 is bridge to SRAM and NB1 is bridge to DDR. + * To ensure that SRAM transfers are not stalled due to + * delays during DDR refreshes, SRAM traffic should be higher + * priority (threadmap=2) than DDR traffic (threadmap=0). + */ + writel(0x2, NAVSS0_NBSS_NB0_CFG_BASE + NAVSS_NBSS_THREADMAP); + writel(0x0, NAVSS0_NBSS_NB1_CFG_BASE + NAVSS_NBSS_THREADMAP); +} + void board_init_f(ulong dummy) { #if defined(CONFIG_K3_LOAD_SYSFW) || defined(CONFIG_K3_AM654_DDRSS) @@ -168,6 +181,8 @@ void board_init_f(ulong dummy) /* Make all control module registers accessible */ ctrl_mmr_unlock();

+ setup_am654_navss_northbridge(); + #ifdef CONFIG_CPU_V7R disable_linefill_optimization(); setup_k3_mpu_regions(); diff --git a/arch/arm/mach-k3/include/mach/am6_hardware.h b/arch/arm/mach-k3/include/mach/am6_hardware.h index 1908a13f0ff2..f533e22e0617 100644 --- a/arch/arm/mach-k3/include/mach/am6_hardware.h +++ b/arch/arm/mach-k3/include/mach/am6_hardware.h @@ -52,4 +52,10 @@ /* MCU SCRATCHPAD usage */ #define TI_SRAM_SCRATCH_BOARD_EEPROM_START CONFIG_SYS_K3_MCU_SCRATCHPAD_BASE

+/* NAVSS Northbridge config */ +#define NAVSS0_NBSS_NB0_CFG_BASE 0x03802000 +#define NAVSS0_NBSS_NB1_CFG_BASE 0x03803000 + +#define NAVSS_NBSS_THREADMAP 0x10 + #endif /* __ASM_ARCH_AM6_HARDWARE_H */