arm: tegra: power: add reference counters for pcie

[sojka/nv-tegra/linux-3.10.git] / arch / arm / mach-tegra / powergate-t12x.c

diff --git a/arch/arm/mach-tegra/powergate-t12x.c b/arch/arm/mach-tegra/powergate-t12x.c
index 8333e8d9cab1f535c62618c132cd388059d78d41..b549892694682ac60c8236dcac4ddaec8a1cba2e 100644 (file)
--- a/arch/arm/mach-tegra/powergate-t12x.c
+++ b/arch/arm/mach-tegra/powergate-t12x.c
@@ -530,6 +530,7 @@ err_power:
 static atomic_t ref_count_dispa = ATOMIC_INIT(0);
 static atomic_t ref_count_dispb = ATOMIC_INIT(0);
 static atomic_t ref_count_venc = ATOMIC_INIT(0);
+static atomic_t ref_count_pcie = ATOMIC_INIT(0);
 
 #define CHECK_RET(x)                   \
        do {                            \
@@ -658,6 +659,42 @@ static int tegra12x_venc_unpowergate(int id)
        return ret;
 }
 
+static int tegra12x_pcie_powergate(int id)
+{
+       int ret = 0;
+       int ref_count = 0;
+
+       if (!TEGRA_IS_PCIE_POWERGATE_ID(id))
+               return -EINVAL;
+
+       ref_count = atomic_dec_return(&ref_count_pcie);
+       WARN_ON(ref_count < 0);
+
+       /* only powergate when decrementing ref_count from 1 to 0 */
+       if (ref_count == 0)
+               CHECK_RET(tegra12x_powergate(id));
+
+       return ret;
+}
+
+static int tegra12x_pcie_unpowergate(int id)
+{
+       int ret = 0;
+       int ref_count = 0;
+
+       if (!TEGRA_IS_PCIE_POWERGATE_ID(id))
+               return -EINVAL;
+
+       ref_count = atomic_inc_return(&ref_count_pcie);
+       WARN_ON(ref_count < 1);
+
+       /* only unpowergate when incrementing ref_count from 0 to 1 */
+       if (ref_count == 1)
+               CHECK_RET(tegra12x_unpowergate(id));
+
+       return ret;
+}
+
 int tegra12x_powergate_partition(int id)
 {
        int ret;
@@ -671,6 +708,8 @@ int tegra12x_powergate_partition(int id)
                ret = tegra_powergate_set(id, false);
        else if (id == TEGRA_POWERGATE_VENC)
                ret = tegra12x_venc_powergate(id);
+       else if (id == TEGRA_POWERGATE_PCIE)
+               ret = tegra12x_pcie_powergate(id);
        else {
                /* call common power-gate API for t1xx */
                ret = tegra1xx_powergate(id,
@@ -693,6 +732,8 @@ int tegra12x_unpowergate_partition(int id)
                ret = tegra_powergate_set(id, true);
        else if (id == TEGRA_POWERGATE_VENC)
                ret = tegra12x_venc_unpowergate(id);
+       else if (id == TEGRA_POWERGATE_PCIE)
+               ret = tegra12x_pcie_unpowergate(id);
        else {
                ret = tegra1xx_unpowergate(id,
                        &tegra12x_powergate_partition_info[id]);
@@ -758,6 +799,7 @@ static int tegra12x_powergate_init_refcount(void)
 {
        bool disa_powered = tegra_powergate_is_powered(TEGRA_POWERGATE_DISA);
        bool venc_powered = tegra_powergate_is_powered(TEGRA_POWERGATE_VENC);
+       bool pcie_powered = tegra_powergate_is_powered(TEGRA_POWERGATE_PCIE);
 
        WARN_ON(venc_powered && !disa_powered);
 
@@ -782,6 +824,15 @@ static int tegra12x_powergate_init_refcount(void)
                atomic_set(&ref_count_venc, 0);
        }
 
+       /* PCIE needs refcount menchanism due to HW Bug#1320346.  PCIE should be
+        * powergated only when both XUSB and PCIE are not active.
+        */
+
+       if (pcie_powered)
+               atomic_set(&ref_count_pcie, 1);
+       else
+               atomic_set(&ref_count_pcie, 0);
+
        return 0;
 }