The code to detect whether Linux has access to group0 interrupts can
prove useful in other parts of the driver.

Provide a separate function to do this.

Tested-by: Daniel Thompson <daniel.thomp...@linaro.org>
Signed-off-by: Julien Thierry <julien.thie...@arm.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Jason Cooper <ja...@lakedaemon.net>
Cc: Marc Zyngier <marc.zyng...@arm.com>
---
 drivers/irqchip/irq-gic-v3.c | 55 +++++++++++++++++++++++++++++---------------
 1 file changed, 36 insertions(+), 19 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index d5912f1..fef6688 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -392,6 +392,39 @@ static asmlinkage void __exception_irq_entry 
gic_handle_irq(struct pt_regs *regs
        } while (irqnr != ICC_IAR1_EL1_SPURIOUS);
 }

+static u32 gic_get_pribits(void)
+{
+       u32 pribits;
+
+       pribits = gic_read_ctlr();
+       pribits &= ICC_CTLR_EL1_PRI_BITS_MASK;
+       pribits >>= ICC_CTLR_EL1_PRI_BITS_SHIFT;
+       pribits++;
+
+       return pribits;
+}
+
+static bool gic_has_group0(void)
+{
+       u32 val;
+
+       /*
+        * Let's find out if Group0 is under control of EL3 or not by
+        * setting the highest possible, non-zero priority in PMR.
+        *
+        * If SCR_EL3.FIQ is set, the priority gets shifted down in
+        * order for the CPU interface to set bit 7, and keep the
+        * actual priority in the non-secure range. In the process, it
+        * looses the least significant bit and the actual priority
+        * becomes 0x80. Reading it back returns 0, indicating that
+        * we're don't have access to Group0.
+        */
+       gic_write_pmr(BIT(8 - gic_get_pribits()));
+       val = gic_read_pmr();
+
+       return val != 0;
+}
+
 static void __init gic_dist_init(void)
 {
        unsigned int i;
@@ -533,7 +566,7 @@ static void gic_cpu_sys_reg_init(void)
        u64 mpidr = cpu_logical_map(cpu);
        u64 need_rss = MPIDR_RS(mpidr);
        bool group0;
-       u32 val, pribits;
+       u32 pribits;

        /*
         * Need to check that the SRE bit has actually been set. If
@@ -545,25 +578,9 @@ static void gic_cpu_sys_reg_init(void)
        if (!gic_enable_sre())
                pr_err("GIC: unable to set SRE (disabled at EL2), panic 
ahead\n");

-       pribits = gic_read_ctlr();
-       pribits &= ICC_CTLR_EL1_PRI_BITS_MASK;
-       pribits >>= ICC_CTLR_EL1_PRI_BITS_SHIFT;
-       pribits++;
+       pribits = gic_get_pribits();

-       /*
-        * Let's find out if Group0 is under control of EL3 or not by
-        * setting the highest possible, non-zero priority in PMR.
-        *
-        * If SCR_EL3.FIQ is set, the priority gets shifted down in
-        * order for the CPU interface to set bit 7, and keep the
-        * actual priority in the non-secure range. In the process, it
-        * looses the least significant bit and the actual priority
-        * becomes 0x80. Reading it back returns 0, indicating that
-        * we're don't have access to Group0.
-        */
-       write_gicreg(BIT(8 - pribits), ICC_PMR_EL1);
-       val = read_gicreg(ICC_PMR_EL1);
-       group0 = val != 0;
+       group0 = gic_has_group0();

        /* Set priority mask register */
        write_gicreg(DEFAULT_PMR_VALUE, ICC_PMR_EL1);
--
1.9.1

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