Commit 408324a3 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven
Browse files

ARM: shmobile: Enable ARM_GLOBAL_TIMER on Cortex-A9 MPCore SoCs 



SH-Mobile AG5 and R-Car H1 SoCs are based on the Cortex-A9 MPCore, which
includes a global timer.

Enable the ARM global timer on these SoCs, which will be used for:
  - the scheduler clock, improving scheduler accuracy from 10 ms to 3 or
    4 ns,
  - delay loops, allowing removal of calls to shmobile_init_delay() from
    the corresponding machine vectors.

Note that when using an old DTB lacking the global timer, the kernel
will still work.  However, loops-per-jiffies will no longer be preset,
and the delay loop will need to be calibrated during boot.

Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20191211135222.26770-5-geert+renesas@glider.be
parent bb6d3fb3

arch/arm/mach-shmobile/setup-r8a7779.c

+0 −1
Original line number Diff line number Diff line
@@ -72,7 +72,6 @@ static const char *const r8a7779_compat_dt[] __initconst = { 
DT_MACHINE_START(R8A7779_DT, "Generic R8A7779 (Flattened Device Tree)")

	.smp		= smp_ops(r8a7779_smp_ops),

	.map_io		= r8a7779_map_io,

	.init_early	= shmobile_init_delay,

	.init_irq	= r8a7779_init_irq_dt,

	.init_late	= shmobile_init_late,

	.dt_compat	= r8a7779_compat_dt,

arch/arm/mach-shmobile/setup-sh73a0.c

+0 −1
Original line number Diff line number Diff line
@@ -56,7 +56,6 @@ static const char *const sh73a0_boards_compat_dt[] __initconst = { 
DT_MACHINE_START(SH73A0_DT, "Generic SH73A0 (Flattened Device Tree)")

	.smp		= smp_ops(sh73a0_smp_ops),

	.map_io		= sh73a0_map_io,

	.init_early	= shmobile_init_delay,

	.init_machine	= sh73a0_generic_init,

	.init_late	= shmobile_init_late,

	.dt_compat	= sh73a0_boards_compat_dt,

drivers/soc/renesas/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -116,6 +116,7 @@ config ARCH_R8A7779 
	bool "R-Car H1 (R8A77790)"

	select ARCH_RCAR_GEN1

	select ARM_ERRATA_754322

	select ARM_GLOBAL_TIMER

	select HAVE_ARM_SCU if SMP

	select HAVE_ARM_TWD if SMP

	select SYSC_R8A7779
@@ -163,6 +164,7 @@ config ARCH_SH73A0 
	bool "SH-Mobile AG5 (R8A73A00)"

	select ARCH_RMOBILE

	select ARM_ERRATA_754322

	select ARM_GLOBAL_TIMER

	select HAVE_ARM_SCU if SMP

	select HAVE_ARM_TWD if SMP

	select RENESAS_INTC_IRQPIN

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