dmaengine: qcom: Add GPI dma driver

This controller provides DMAengine capabilities for a variety of peripheral
buses such as I2C, UART, and SPI. By using GPI dmaengine driver, bus
drivers can use a standardize interface that is protocol independent to
transfer data between memory and peripheral.

Link: https://lore.kernel.org/r/20201109085450.24843-4-vkoul@kernel.orgSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/qcom/Kconfig

@@ -19,6 +19,18 @@ config QCOM_BAM_DMA
 	  Enable support for the QCOM BAM DMA controller.  This controller
 	  provides DMA capabilities for a variety of on-chip devices.
 
+config QCOM_GPI_DMA
+        tristate "Qualcomm Technologies GPI DMA support"
+        depends on ARCH_QCOM
+        select DMA_ENGINE
+        select DMA_VIRTUAL_CHANNELS
+        help
+          Enable support for the QCOM GPI DMA controller. This controller
+          provides DMA capabilities for a variety of peripheral buses such
+          as I2C, UART, and SPI. By using GPI dmaengine driver, bus drivers
+          can use a standardize interface that is protocol independent to
+          transfer data between DDR and peripheral.
+
 config QCOM_HIDMA_MGMT
 	tristate "Qualcomm Technologies HIDMA Management support"
 	select DMA_ENGINE

drivers/dma/qcom/Makefile

 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_QCOM_ADM) += qcom_adm.o
 obj-$(CONFIG_QCOM_BAM_DMA) += bam_dma.o
+obj-$(CONFIG_QCOM_GPI_DMA) += gpi.o
 obj-$(CONFIG_QCOM_HIDMA_MGMT) += hdma_mgmt.o
 hdma_mgmt-objs	 := hidma_mgmt.o hidma_mgmt_sys.o
 obj-$(CONFIG_QCOM_HIDMA) +=  hdma.o

include/linux/dma/qcom-gpi-dma.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2020, Linaro Limited
+ */
+
+#ifndef QCOM_GPI_DMA_H
+#define QCOM_GPI_DMA_H
+
+/**
+ * enum spi_transfer_cmd - spi transfer commands
+ */
+enum spi_transfer_cmd {
+	SPI_TX = 1,
+	SPI_RX,
+	SPI_DUPLEX,
+};
+
+/**
+ * struct gpi_spi_config - spi config for peripheral
+ *
+ * @loopback_en: spi loopback enable when set
+ * @clock_pol_high: clock polarity
+ * @data_pol_high: data polarity
+ * @pack_en: process tx/rx buffers as packed
+ * @word_len: spi word length
+ * @clk_div: source clock divider
+ * @clk_src: serial clock
+ * @cmd: spi cmd
+ * @fragmentation: keep CS assserted at end of sequence
+ * @cs: chip select toggle
+ * @set_config: set peripheral config
+ * @rx_len: receive length for buffer
+ */
+struct gpi_spi_config {
+	u8 set_config;
+	u8 loopback_en;
+	u8 clock_pol_high;
+	u8 data_pol_high;
+	u8 pack_en;
+	u8 word_len;
+	u8 fragmentation;
+	u8 cs;
+	u32 clk_div;
+	u32 clk_src;
+	enum spi_transfer_cmd cmd;
+	u32 rx_len;
+};
+
+enum i2c_op {
+	I2C_WRITE = 1,
+	I2C_READ,
+};
+
+/**
+ * struct gpi_i2c_config - i2c config for peripheral
+ *
+ * @pack_enable: process tx/rx buffers as packed
+ * @cycle_count: clock cycles to be sent
+ * @high_count: high period of clock
+ * @low_count: low period of clock
+ * @clk_div: source clock divider
+ * @addr: i2c bus address
+ * @stretch: stretch the clock at eot
+ * @set_config: set peripheral config
+ * @rx_len: receive length for buffer
+ * @op: i2c cmd
+ * @muli-msg: is part of multi i2c r-w msgs
+ */
+struct gpi_i2c_config {
+	u8 set_config;
+	u8 pack_enable;
+	u8 cycle_count;
+	u8 high_count;
+	u8 low_count;
+	u8 addr;
+	u8 stretch;
+	u16 clk_div;
+	u32 rx_len;
+	enum i2c_op op;
+	bool multi_msg;
+};
+
+#endif /* QCOM_GPI_DMA_H */