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-rw-r--r--Documentation/arm64/silicon-errata.txt2
-rw-r--r--Documentation/kernel-parameters.txt9
-rw-r--r--arch/arm64/include/asm/arch_timer.h47
-rw-r--r--drivers/clocksource/Kconfig10
-rw-r--r--drivers/clocksource/arm_arch_timer.c104
5 files changed, 169 insertions, 3 deletions
diff --git a/Documentation/arm64/silicon-errata.txt b/Documentation/arm64/silicon-errata.txt
index 4da60b463995..041e3a943784 100644
--- a/Documentation/arm64/silicon-errata.txt
+++ b/Documentation/arm64/silicon-errata.txt
@@ -60,3 +60,5 @@ stable kernels.
| Cavium | ThunderX GICv3 | #23154 | CAVIUM_ERRATUM_23154 |
| Cavium | ThunderX Core | #27456 | CAVIUM_ERRATUM_27456 |
| Cavium | ThunderX SMMUv2 | #27704 | N/A |
+| | | | |
+| Freescale/NXP | LS2080A/LS1043A | A-008585 | FSL_ERRATUM_A008585 |
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 46c030a49186..fb4de4daba1f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -698,6 +698,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
loops can be debugged more effectively on production
systems.
+ clocksource.arm_arch_timer.fsl-a008585=
+ [ARM64]
+ Format: <bool>
+ Enable/disable the workaround of Freescale/NXP
+ erratum A-008585. This can be useful for KVM
+ guests, if the guest device tree doesn't show the
+ erratum. If unspecified, the workaround is
+ enabled based on the device tree.
+
clearcpuid=BITNUM [X86]
Disable CPUID feature X for the kernel. See
arch/x86/include/asm/cpufeatures.h for the valid bit
diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
index 7ff386c15539..eaa5bbe3fa87 100644
--- a/arch/arm64/include/asm/arch_timer.h
+++ b/arch/arm64/include/asm/arch_timer.h
@@ -24,10 +24,51 @@
#include <linux/bug.h>
#include <linux/init.h>
+#include <linux/jump_label.h>
#include <linux/types.h>
#include <clocksource/arm_arch_timer.h>
+#if IS_ENABLED(CONFIG_FSL_ERRATUM_A008585)
+extern struct static_key_false arch_timer_read_ool_enabled;
+#define needs_fsl_a008585_workaround() \
+ static_branch_unlikely(&arch_timer_read_ool_enabled)
+#else
+#define needs_fsl_a008585_workaround() false
+#endif
+
+u32 __fsl_a008585_read_cntp_tval_el0(void);
+u32 __fsl_a008585_read_cntv_tval_el0(void);
+u64 __fsl_a008585_read_cntvct_el0(void);
+
+/*
+ * The number of retries is an arbitrary value well beyond the highest number
+ * of iterations the loop has been observed to take.
+ */
+#define __fsl_a008585_read_reg(reg) ({ \
+ u64 _old, _new; \
+ int _retries = 200; \
+ \
+ do { \
+ _old = read_sysreg(reg); \
+ _new = read_sysreg(reg); \
+ _retries--; \
+ } while (unlikely(_old != _new) && _retries); \
+ \
+ WARN_ON_ONCE(!_retries); \
+ _new; \
+})
+
+#define arch_timer_reg_read_stable(reg) \
+({ \
+ u64 _val; \
+ if (needs_fsl_a008585_workaround()) \
+ _val = __fsl_a008585_read_##reg(); \
+ else \
+ _val = read_sysreg(reg); \
+ _val; \
+})
+
/*
* These register accessors are marked inline so the compiler can
* nicely work out which register we want, and chuck away the rest of
@@ -67,14 +108,14 @@ u32 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
case ARCH_TIMER_REG_CTRL:
return read_sysreg(cntp_ctl_el0);
case ARCH_TIMER_REG_TVAL:
- return read_sysreg(cntp_tval_el0);
+ return arch_timer_reg_read_stable(cntp_tval_el0);
}
} else if (access == ARCH_TIMER_VIRT_ACCESS) {
switch (reg) {
case ARCH_TIMER_REG_CTRL:
return read_sysreg(cntv_ctl_el0);
case ARCH_TIMER_REG_TVAL:
- return read_sysreg(cntv_tval_el0);
+ return arch_timer_reg_read_stable(cntv_tval_el0);
}
}
@@ -108,7 +149,7 @@ static inline u64 arch_counter_get_cntpct(void)
static inline u64 arch_counter_get_cntvct(void)
{
isb();
- return read_sysreg(cntvct_el0);
+ return arch_timer_reg_read_stable(cntvct_el0);
}
static inline int arch_timer_arch_init(void)
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 567788664723..8a753fd5b79d 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -305,6 +305,16 @@ config ARM_ARCH_TIMER_EVTSTREAM
This must be disabled for hardware validation purposes to detect any
hardware anomalies of missing events.
+config FSL_ERRATUM_A008585
+ bool "Workaround for Freescale/NXP Erratum A-008585"
+ default y
+ depends on ARM_ARCH_TIMER && ARM64
+ help
+ This option enables a workaround for Freescale/NXP Erratum
+ A-008585 ("ARM generic timer may contain an erroneous
+ value"). The workaround will only be active if the
+ fsl,erratum-a008585 property is found in the timer node.
+
config ARM_GLOBAL_TIMER
bool "Support for the ARM global timer" if COMPILE_TEST
select CLKSRC_OF if OF
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 57700541f951..eb5fb4121ac8 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -94,6 +94,43 @@ early_param("clocksource.arm_arch_timer.evtstrm", early_evtstrm_cfg);
* Architected system timer support.
*/
+#ifdef CONFIG_FSL_ERRATUM_A008585
+DEFINE_STATIC_KEY_FALSE(arch_timer_read_ool_enabled);
+EXPORT_SYMBOL_GPL(arch_timer_read_ool_enabled);
+
+static int fsl_a008585_enable = -1;
+
+static int __init early_fsl_a008585_cfg(char *buf)
+{
+ int ret;
+ bool val;
+
+ ret = strtobool(buf, &val);
+ if (ret)
+ return ret;
+
+ fsl_a008585_enable = val;
+ return 0;
+}
+early_param("clocksource.arm_arch_timer.fsl-a008585", early_fsl_a008585_cfg);
+
+u32 __fsl_a008585_read_cntp_tval_el0(void)
+{
+ return __fsl_a008585_read_reg(cntp_tval_el0);
+}
+
+u32 __fsl_a008585_read_cntv_tval_el0(void)
+{
+ return __fsl_a008585_read_reg(cntv_tval_el0);
+}
+
+u64 __fsl_a008585_read_cntvct_el0(void)
+{
+ return __fsl_a008585_read_reg(cntvct_el0);
+}
+EXPORT_SYMBOL(__fsl_a008585_read_cntvct_el0);
+#endif /* CONFIG_FSL_ERRATUM_A008585 */
+
static __always_inline
void arch_timer_reg_write(int access, enum arch_timer_reg reg, u32 val,
struct clock_event_device *clk)
@@ -243,6 +280,40 @@ static __always_inline void set_next_event(const int access, unsigned long evt,
arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
}
+#ifdef CONFIG_FSL_ERRATUM_A008585
+static __always_inline void fsl_a008585_set_next_event(const int access,
+ unsigned long evt, struct clock_event_device *clk)
+{
+ unsigned long ctrl;
+ u64 cval = evt + arch_counter_get_cntvct();
+
+ ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
+ ctrl |= ARCH_TIMER_CTRL_ENABLE;
+ ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
+
+ if (access == ARCH_TIMER_PHYS_ACCESS)
+ write_sysreg(cval, cntp_cval_el0);
+ else if (access == ARCH_TIMER_VIRT_ACCESS)
+ write_sysreg(cval, cntv_cval_el0);
+
+ arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
+}
+
+static int fsl_a008585_set_next_event_virt(unsigned long evt,
+ struct clock_event_device *clk)
+{
+ fsl_a008585_set_next_event(ARCH_TIMER_VIRT_ACCESS, evt, clk);
+ return 0;
+}
+
+static int fsl_a008585_set_next_event_phys(unsigned long evt,
+ struct clock_event_device *clk)
+{
+ fsl_a008585_set_next_event(ARCH_TIMER_PHYS_ACCESS, evt, clk);
+ return 0;
+}
+#endif /* CONFIG_FSL_ERRATUM_A008585 */
+
static int arch_timer_set_next_event_virt(unsigned long evt,
struct clock_event_device *clk)
{
@@ -271,6 +342,19 @@ static int arch_timer_set_next_event_phys_mem(unsigned long evt,
return 0;
}
+static void fsl_a008585_set_sne(struct clock_event_device *clk)
+{
+#ifdef CONFIG_FSL_ERRATUM_A008585
+ if (!static_branch_unlikely(&arch_timer_read_ool_enabled))
+ return;
+
+ if (arch_timer_uses_ppi == VIRT_PPI)
+ clk->set_next_event = fsl_a008585_set_next_event_virt;
+ else
+ clk->set_next_event = fsl_a008585_set_next_event_phys;
+#endif
+}
+
static void __arch_timer_setup(unsigned type,
struct clock_event_device *clk)
{
@@ -299,6 +383,8 @@ static void __arch_timer_setup(unsigned type,
default:
BUG();
}
+
+ fsl_a008585_set_sne(clk);
} else {
clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
clk->name = "arch_mem_timer";
@@ -515,6 +601,15 @@ static void __init arch_counter_register(unsigned type)
arch_timer_read_counter = arch_counter_get_cntvct;
else
arch_timer_read_counter = arch_counter_get_cntpct;
+
+#ifdef CONFIG_FSL_ERRATUM_A008585
+ /*
+ * Don't use the vdso fastpath if errata require using
+ * the out-of-line counter accessor.
+ */
+ if (static_branch_unlikely(&arch_timer_read_ool_enabled))
+ clocksource_counter.name = "arch_sys_counter_ool";
+#endif
} else {
arch_timer_read_counter = arch_counter_get_cntvct_mem;
@@ -800,6 +895,15 @@ static int __init arch_timer_of_init(struct device_node *np)
arch_timer_c3stop = !of_property_read_bool(np, "always-on");
+#ifdef CONFIG_FSL_ERRATUM_A008585
+ if (fsl_a008585_enable < 0)
+ fsl_a008585_enable = of_property_read_bool(np, "fsl,erratum-a008585");
+ if (fsl_a008585_enable) {
+ static_branch_enable(&arch_timer_read_ool_enabled);
+ pr_info("Enabling workaround for FSL erratum A-008585\n");
+ }
+#endif
+
/*
* If we cannot rely on firmware initializing the timer registers then
* we should use the physical timers instead.