[PATCH v3 25/25] ARM: owl: smp: Reimplement SPS power-gating for CPU2 and CPU3

[Andreas Färber]

Bring up the two remaining CPUs.

Based on LeMaker linux-actions tree.

Signed-off-by: Andreas Färber <afaer...@suse.de>
---
 v3: new
 
 arch/arm/mach-actions/platsmp.c | 67 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 65 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-actions/platsmp.c b/arch/arm/mach-actions/platsmp.c
index 9d3601e..45b4bc5 100644
--- a/arch/arm/mach-actions/platsmp.c
+++ b/arch/arm/mach-actions/platsmp.c
@@ -28,7 +28,15 @@
 
 #define OWL_CPUx_FLAG_BOOT     0x55aa
 
+#define OWL_SPS_PG_CTL 0x0
+
+#define OWL_SPS_PG_CTL_PWR_CPU2        BIT(5)
+#define OWL_SPS_PG_CTL_PWR_CPU3        BIT(6)
+#define OWL_SPS_PG_CTL_ACK_CPU2        BIT(21)
+#define OWL_SPS_PG_CTL_ACK_CPU3        BIT(22)
+
 static void __iomem *scu_base_addr;
+static void __iomem *sps_base_addr;
 static void __iomem *timer_base_addr;
 static int ncores;
 
@@ -42,6 +50,39 @@ static void write_pen_release(int val)
        outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
 }
 
+/* The generic PM domain driver is not available this early. */
+static int owl_sps_set_pg(u32 pwr_mask, u32 ack_mask, bool enable)
+{
+       u32 val;
+       bool ack;
+       int timeout;
+
+       val = readl(sps_base_addr + OWL_SPS_PG_CTL);
+       ack = val & ack_mask;
+       if (ack == enable)
+               return 0;
+
+       if (enable)
+               val |= pwr_mask;
+       else
+               val &= ~pwr_mask;
+
+       writel(val, sps_base_addr + OWL_SPS_PG_CTL);
+
+       for (timeout = 5000; timeout > 0; timeout -= 50) {
+               val = readl(sps_base_addr + OWL_SPS_PG_CTL);
+               if ((val & ack_mask) == (enable ? ack_mask : 0))
+                       break;
+               udelay(50);
+       }
+       if (timeout <= 0)
+               return -ETIMEDOUT;
+
+       udelay(10);
+
+       return 0;
+}
+
 static void s500_smp_secondary_init(unsigned int cpu)
 {
        /*
@@ -58,14 +99,24 @@ void owl_secondary_startup(void);
 
 static int s500_wakeup_secondary(unsigned int cpu)
 {
+       int ret;
+
        if (cpu > 3)
                return -EINVAL;
 
        switch (cpu) {
        case 2:
+               ret = owl_sps_set_pg(OWL_SPS_PG_CTL_PWR_CPU2,
+                                    OWL_SPS_PG_CTL_ACK_CPU2, true);
+               if (ret)
+                       return ret;
+               break;
        case 3:
-               /* CPU2/3 are power-gated */
-               return -EINVAL;
+               ret = owl_sps_set_pg(OWL_SPS_PG_CTL_PWR_CPU3,
+                                    OWL_SPS_PG_CTL_ACK_CPU3, true);
+               if (ret)
+                       return ret;
+               break;
        }
 
        /* wait for CPUx to run to WFE instruction */
@@ -133,6 +184,18 @@ static void __init s500_smp_prepare_cpus(unsigned int 
max_cpus)
                return;
        }
 
+       node = of_find_compatible_node(NULL, NULL, "actions,s500-sps");
+       if (!node) {
+               pr_err("%s: missing sps\n", __func__);
+               return;
+       }
+
+       sps_base_addr = of_iomap(node, 0);
+       if (!sps_base_addr) {
+               pr_err("%s: could not map sps registers\n", __func__);
+               return;
+       }
+
        if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A9) {
                node = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
                if (!node) {
-- 
2.10.2