soc: qcom: Separate kryo l2 accessors from PMU driver

The driver provides kernel level API for other drivers
to access the MSM8996 L2 cache registers.
Separating the L2 access code from the PMU driver and
making it public to allow other drivers use it.
The accesses must be separated with a single spinlock,
maintained in this driver.

Signed-off-by: Ilia Lin <ilialin@codeaurora.org>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Link: https://lore.kernel.org/r/1593766185-16346-2-git-send-email-loic.poulain@linaro.org
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

1 files changed, 57 insertions, 0 deletions

diff --git a/drivers/soc/qcom/kryo-l2-accessors.c b/drivers/soc/qcom/kryo-l2-accessors.c
new file mode 100644
index 000000000000..c20cb92077c0
--- /dev/null
+++ b/drivers/soc/qcom/kryo-l2-accessors.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/spinlock.h>
+#include <asm/barrier.h>
+#include <asm/sysreg.h>
+#include <soc/qcom/kryo-l2-accessors.h>
+
+#define L2CPUSRSELR_EL1         sys_reg(3, 3, 15, 0, 6)
+#define L2CPUSRDR_EL1           sys_reg(3, 3, 15, 0, 7)
+
+static DEFINE_RAW_SPINLOCK(l2_access_lock);
+
+/**
+ * kryo_l2_set_indirect_reg() - write value to an L2 register
+ * @reg: Address of L2 register.
+ * @value: Value to be written to register.
+ *
+ * Use architecturally required barriers for ordering between system register
+ * accesses, and system registers with respect to device memory
+ */
+void kryo_l2_set_indirect_reg(u64 reg, u64 val)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&l2_access_lock, flags);
+	write_sysreg_s(reg, L2CPUSRSELR_EL1);
+	isb();
+	write_sysreg_s(val, L2CPUSRDR_EL1);
+	isb();
+	raw_spin_unlock_irqrestore(&l2_access_lock, flags);
+}
+EXPORT_SYMBOL(kryo_l2_set_indirect_reg);
+
+/**
+ * kryo_l2_get_indirect_reg() - read an L2 register value
+ * @reg: Address of L2 register.
+ *
+ * Use architecturally required barriers for ordering between system register
+ * accesses, and system registers with respect to device memory
+ */
+u64 kryo_l2_get_indirect_reg(u64 reg)
+{
+	u64 val;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&l2_access_lock, flags);
+	write_sysreg_s(reg, L2CPUSRSELR_EL1);
+	isb();
+	val = read_sysreg_s(L2CPUSRDR_EL1);
+	raw_spin_unlock_irqrestore(&l2_access_lock, flags);
+
+	return val;
+}
+EXPORT_SYMBOL(kryo_l2_get_indirect_reg);