Messages in this thread Patch in this message | | | From | Shanker Donthineni <> | Subject | [PATCH] irqchip/gic-v3: Ensure GICR_CTLR.EnableLPI=0 is observed before enabling | Date | Tue, 13 Mar 2018 19:50:01 -0500 |
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The definition of the GICR_CTLR.RWP control bit was expanded to indicate status of changing GICR_CTLR.EnableLPI from 1 to 0 is being in progress or completed. Software must observe GICR_CTLR.RWP==0 after clearing GICR_CTLR.EnableLPI from 1 to 0 and before writing GICR_PENDBASER and/or GICR_PROPBASER, otherwise behavior is UNPREDICTABLE.
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org> --- drivers/irqchip/irq-gic-v3-its.c | 30 +++++++++++++++++++++++------- include/linux/irqchip/arm-gic-v3.h | 1 + 2 files changed, 24 insertions(+), 7 deletions(-)
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index 1d3056f..85cd158 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -1875,15 +1875,31 @@ static void its_cpu_init_lpis(void) gic_data_rdist()->pend_page = pend_page; } - /* Disable LPIs */ val = readl_relaxed(rbase + GICR_CTLR); - val &= ~GICR_CTLR_ENABLE_LPIS; - writel_relaxed(val, rbase + GICR_CTLR); - /* - * Make sure any change to the table is observable by the GIC. - */ - dsb(sy); + /* Make sure LPIs are disabled before programming PEND/PROP registers */ + if (val & GICR_CTLR_ENABLE_LPIS) { + u32 count = 1000000; /* 1s! */ + + /* Disable LPIs */ + val &= ~GICR_CTLR_ENABLE_LPIS; + writel_relaxed(val, rbase + GICR_CTLR); + + /* Make sure any change to GICR_CTLR is observable by the GIC */ + dsb(sy); + + /* Wait for GICR_CTLR.RWP==0 or timeout */ + while (readl_relaxed(rbase + GICR_CTLR) & GICR_CTLR_RWP) { + if (!count) { + pr_err("CPU%d: Failed to disable LPIs\n", + smp_processor_id()); + return; + } + cpu_relax(); + udelay(1); + count--; + }; + } /* set PROPBASE */ val = (page_to_phys(gic_rdists->prop_page) | diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h index c00c4c33..4d5fb60 100644 --- a/include/linux/irqchip/arm-gic-v3.h +++ b/include/linux/irqchip/arm-gic-v3.h @@ -106,6 +106,7 @@ #define GICR_PIDR2 GICD_PIDR2 #define GICR_CTLR_ENABLE_LPIS (1UL << 0) +#define GICR_CTLR_RWP (1UL << 3) #define GICR_TYPER_CPU_NUMBER(r) (((r) >> 8) & 0xffff) -- Qualcomm Datacenter Technologies, Inc. on behalf of the Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
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