soc: qcom: add OCMEM driver

The OCMEM driver handles allocation and configuration of the On Chip
MEMory that is present on some Snapdragon SoCs. Devices which have
OCMEM do not have GMEM inside the GPU core, so the GPU must instead
use OCMEM to be functional. Since the GPU is currently the only OCMEM
user with an upstream driver, this is just a minimal implementation
sufficient for statically allocating to the GPU it's chunk of OCMEM.

This driver currently does not read the gmu-sram node that is described
in the device tree bindings. The starting memory address of the GPU's
reserved memory region is hardcoded to zero to match what the hardware
expects. The driver can be updated to read the reserved memory regions
from device tree once other users of OCMEM are added upstream.
Signed-off-by: Brian Masney <masneyb@onstation.org>
Co-developed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Tested-by: Gabriel Francisco <frc.gabrielgmail.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/soc/qcom/Kconfig

@@ -74,6 +74,16 @@ config QCOM_MDT_LOADER
 	tristate
 	select QCOM_SCM
 
+config QCOM_OCMEM
+	tristate "Qualcomm On Chip Memory (OCMEM) driver"
+	depends on ARCH_QCOM
+	select QCOM_SCM
+	help
+          The On Chip Memory (OCMEM) allocator allows various clients to
+          allocate memory from OCMEM based on performance, latency and power
+          requirements. This is typically used by the GPU, camera/video, and
+          audio components on some Snapdragon SoCs.
+
 config QCOM_PM
 	bool "Qualcomm Power Management"
 	depends on ARCH_QCOM && !ARM64

drivers/soc/qcom/Makefile

@@ -6,6 +6,7 @@ obj-$(CONFIG_QCOM_COMMAND_DB) += cmd-db.o
 obj-$(CONFIG_QCOM_GLINK_SSR) +=	glink_ssr.o
 obj-$(CONFIG_QCOM_GSBI)	+=	qcom_gsbi.o
 obj-$(CONFIG_QCOM_MDT_LOADER)	+= mdt_loader.o
+obj-$(CONFIG_QCOM_OCMEM)	+= ocmem.o
 obj-$(CONFIG_QCOM_PM)	+=	spm.o
 obj-$(CONFIG_QCOM_QMI_HELPERS)	+= qmi_helpers.o
 qmi_helpers-y	+= qmi_encdec.o qmi_interface.o

include/soc/qcom/ocmem.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * The On Chip Memory (OCMEM) allocator allows various clients to allocate
+ * memory from OCMEM based on performance, latency and power requirements.
+ * This is typically used by the GPU, camera/video, and audio components on
+ * some Snapdragon SoCs.
+ *
+ * Copyright (C) 2019 Brian Masney <masneyb@onstation.org>
+ * Copyright (C) 2015 Red Hat. Author: Rob Clark <robdclark@gmail.com>
+ */
+
+#ifndef __OCMEM_H__
+#define __OCMEM_H__
+
+enum ocmem_client {
+	/* GMEM clients */
+	OCMEM_GRAPHICS = 0x0,
+	/*
+	 * TODO add more once ocmem_allocate() is clever enough to
+	 * deal with multiple clients.
+	 */
+	OCMEM_CLIENT_MAX,
+};
+
+struct ocmem;
+
+struct ocmem_buf {
+	unsigned long offset;
+	unsigned long addr;
+	unsigned long len;
+};
+
+#if IS_ENABLED(CONFIG_QCOM_OCMEM)
+
+struct ocmem *of_get_ocmem(struct device *dev);
+struct ocmem_buf *ocmem_allocate(struct ocmem *ocmem, enum ocmem_client client,
+				 unsigned long size);
+void ocmem_free(struct ocmem *ocmem, enum ocmem_client client,
+		struct ocmem_buf *buf);
+
+#else /* IS_ENABLED(CONFIG_QCOM_OCMEM) */
+
+static inline struct ocmem *of_get_ocmem(struct device *dev)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline struct ocmem_buf *ocmem_allocate(struct ocmem *ocmem,
+					       enum ocmem_client client,
+					       unsigned long size)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline void ocmem_free(struct ocmem *ocmem, enum ocmem_client client,
+			      struct ocmem_buf *buf)
+{
+}
+
+#endif /* IS_ENABLED(CONFIG_QCOM_OCMEM) */
+
+#endif /* __OCMEM_H__ */