[PATCH v3 2/8] drivers/soc: Add Aspeed XDMA Engine Driver

Eddie James
2019-05-29T18:10:26Z

The XDMA engine embedded in the AST2500 SOC performs PCI DMA operations
between the SOC (acting as a BMC) and a host processor in a server.

This commit adds a driver to control the XDMA engine and adds functions
to initialize the hardware and memory and start DMA operations.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
MAINTAINERS | 10 +
drivers/soc/aspeed/Kconfig | 8 +
drivers/soc/aspeed/Makefile | 1 +
drivers/soc/aspeed/aspeed-xdma.c | 520 +++++++++++++++++++++++++++++++++++++++
include/uapi/linux/aspeed-xdma.h | 26 ++
5 files changed, 565 insertions(+)
create mode 100644 drivers/soc/aspeed/aspeed-xdma.c
create mode 100644 include/uapi/linux/aspeed-xdma.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 7e09dda..84e2b62 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2584,6 +2584,16 @@ S: Maintained
F: drivers/media/platform/aspeed-video.c
F: Documentation/devicetree/bindings/media/aspeed-video.txt

+ASPEED XDMA ENGINE DRIVER
+M: Eddie James <eajames@linux.ibm.com>
+L: linux-aspeed@lists.ozlabs.org (moderated for non-subscribers)
+L: linux-kernel@vger.kernel.org
+S: Maintained
+F: Documentation/devicetree/bindings/misc/aspeed,xdma.txt
+F: Documentation/ABI/testing/sysfs-devices-platform-aspeed-xdma
+F: drivers/soc/aspeed/aspeed-xdma.c
+F: include/uapi/linux/aspeed-xdma.h
+
ASUS NOTEBOOKS AND EEEPC ACPI/WMI EXTRAS DRIVERS
M: Corentin Chary <corentin.chary@gmail.com>
L: acpi4asus-user@lists.sourceforge.net
diff --git a/drivers/soc/aspeed/Kconfig b/drivers/soc/aspeed/Kconfig
index 323e177..8b08310 100644
--- a/drivers/soc/aspeed/Kconfig
+++ b/drivers/soc/aspeed/Kconfig
@@ -29,4 +29,12 @@ config ASPEED_P2A_CTRL
ioctl()s, the driver also provides an interface for userspace mappings to
a pre-defined region.

+config ASPEED_XDMA
+ tristate "Aspeed XDMA Engine Driver"
+ depends on SOC_ASPEED && REGMAP && MFD_SYSCON && HAS_DMA
+ help
+ Enable support for the Aspeed XDMA Engine found on the Aspeed AST2500
+ SOC. The XDMA engine can perform automatic PCI DMA operations between
+ the AST2500 (acting as a BMC) and a host processor.
+
endmenu
diff --git a/drivers/soc/aspeed/Makefile b/drivers/soc/aspeed/Makefile
index b64be47..977b046 100644
--- a/drivers/soc/aspeed/Makefile
+++ b/drivers/soc/aspeed/Makefile
@@ -2,3 +2,4 @@
obj-$(CONFIG_ASPEED_LPC_CTRL) += aspeed-lpc-ctrl.o
obj-$(CONFIG_ASPEED_LPC_SNOOP) += aspeed-lpc-snoop.o
obj-$(CONFIG_ASPEED_P2A_CTRL) += aspeed-p2a-ctrl.o
+obj-$(CONFIG_ASPEED_XDMA) += aspeed-xdma.o
diff --git a/drivers/soc/aspeed/aspeed-xdma.c b/drivers/soc/aspeed/aspeed-xdma.c
new file mode 100644
index 0000000..3dc0ce4
--- /dev/null
+++ b/drivers/soc/aspeed/aspeed-xdma.c
@@ -0,0 +1,520 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright IBM Corp 2019
+
+#include <linux/aspeed-xdma.h>
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/fs.h>
+#include <linux/genalloc.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/list.h>
+#include <linux/mfd/syscon.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_reserved_mem.h>
+#include <linux/platform_device.h>
+#include <linux/poll.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+#include <linux/wait.h>
+
+#define DEVICE_NAME "aspeed-xdma"
+
+#define SCU_STRAP 0x070
+#define SCU_STRAP_VGA_MEM GENMASK(3, 2)
+
+#define SCU_PCIE_CONF 0x180
+#define SCU_PCIE_CONF_VGA_EN BIT(0)
+#define SCU_PCIE_CONF_VGA_EN_MMIO BIT(1)
+#define SCU_PCIE_CONF_VGA_EN_LPC BIT(2)
+#define SCU_PCIE_CONF_VGA_EN_MSI BIT(3)
+#define SCU_PCIE_CONF_VGA_EN_MCTP BIT(4)
+#define SCU_PCIE_CONF_VGA_EN_IRQ BIT(5)
+#define SCU_PCIE_CONF_VGA_EN_DMA BIT(6)
+#define SCU_PCIE_CONF_BMC_EN BIT(8)
+#define SCU_PCIE_CONF_BMC_EN_MMIO BIT(9)
+#define SCU_PCIE_CONF_BMC_EN_MSI BIT(11)
+#define SCU_PCIE_CONF_BMC_EN_MCTP BIT(12)
+#define SCU_PCIE_CONF_BMC_EN_IRQ BIT(13)
+#define SCU_PCIE_CONF_BMC_EN_DMA BIT(14)
+#define SCU_PCIE_CONF_RSVD GENMASK(19, 18)
+
+#define SDMC_CONF 0x004
+#define SDMC_CONF_MEM GENMASK(1, 0)
+#define SDMC_REMAP 0x008
+#define SDMC_REMAP_MAGIC GENMASK(17, 16)
+
+#define XDMA_CMD_SIZE 4
+#define XDMA_CMDQ_SIZE PAGE_SIZE
+#define XDMA_BYTE_ALIGN 16
+#define XDMA_MAX_LINE_SIZE BIT(10)
+#define XDMA_NUM_CMDS \
+ (XDMA_CMDQ_SIZE / sizeof(struct aspeed_xdma_cmd))
+#define XDMA_NUM_DEBUGFS_REGS 6
+
+#define XDMA_CMD_BMC_CHECK BIT(0)
+#define XDMA_CMD_BMC_ADDR GENMASK(29, 4)
+#define XDMA_CMD_BMC_DIR_US BIT(31)
+
+#define XDMA_CMD_COMM1_HI_HOST_PITCH GENMASK(14, 3)
+#define XDMA_CMD_COMM1_HI_BMC_PITCH GENMASK(30, 19)
+
+#define XDMA_CMD_CONF_CHECK BIT(1)
+#define XDMA_CMD_CONF_LINE_SIZE GENMASK(14, 4)
+#define XDMA_CMD_CONF_IRQ_BMC BIT(15)
+#define XDMA_CMD_CONF_NUM_LINES GENMASK(27, 16)
+#define XDMA_CMD_CONF_IRQ BIT(31)
+
+#define XDMA_CMD_ID_UPDIR GENMASK(17, 16)
+#define XDMA_CMD_ID_UPDIR_BMC 0
+#define XDMA_CMD_ID_UPDIR_HOST 1
+#define XDMA_CMD_ID_UPDIR_VGA 2
+
+#define XDMA_DS_PCIE_REQ_SIZE_128 0
+#define XDMA_DS_PCIE_REQ_SIZE_256 1
+#define XDMA_DS_PCIE_REQ_SIZE_512 2
+#define XDMA_DS_PCIE_REQ_SIZE_1K 3
+#define XDMA_DS_PCIE_REQ_SIZE_2K 4
+#define XDMA_DS_PCIE_REQ_SIZE_4K 5
+
+#define XDMA_BMC_CMD_QUEUE_ADDR 0x10
+#define XDMA_BMC_CMD_QUEUE_ENDP 0x14
+#define XDMA_BMC_CMD_QUEUE_WRITEP 0x18
+#define XDMA_BMC_CMD_QUEUE_READP 0x1c
+#define XDMA_BMC_CMD_QUEUE_READP_MAGIC 0xee882266
+#define XDMA_CTRL 0x20
+#define XDMA_CTRL_US_COMP BIT(4)
+#define XDMA_CTRL_DS_COMP BIT(5)
+#define XDMA_CTRL_DS_DIRTY BIT(6)
+#define XDMA_CTRL_DS_PCIE_REQ_SIZE GENMASK(19, 17)
+#define XDMA_CTRL_DS_DATA_TIMEOUT BIT(28)
+#define XDMA_CTRL_DS_CHECK_ID BIT(29)
+#define XDMA_STATUS 0x24
+#define XDMA_STATUS_US_COMP BIT(4)
+#define XDMA_STATUS_DS_COMP BIT(5)
+
+enum {
+ XDMA_IN_PRG,
+ XDMA_UPSTREAM,
+};
+
+struct aspeed_xdma_cmd {
+ u32 host_addr_lo;
+ u32 host_addr_hi;
+ u32 bmc_addr;
+ u32 comm1_hi;
+ u32 conf;
+ u32 id;
+ u32 resv0;
+ u32 resv1;
+};
+
+struct aspeed_xdma_client;
+
+struct aspeed_xdma {
+ struct device *dev;
+ void __iomem *base;
+ struct regmap *scu;
+ struct reset_control *reset;
+
+ unsigned long flags;
+ unsigned int cmd_idx;
+ wait_queue_head_t wait;
+ struct aspeed_xdma_client *current_client;
+
+ u32 vga_phys;
+ u32 vga_size;
+ dma_addr_t vga_dma;
+ void *cmdq;
+ void *vga_virt;
+ dma_addr_t cmdq_vga_phys;
+ void *cmdq_vga_virt;
+ struct gen_pool *vga_pool;
+};
+
+struct aspeed_xdma_client {
+ struct aspeed_xdma *ctx;
+
+ unsigned long flags;
+ void *virt;
+ dma_addr_t phys;
+ u32 size;
+};
+
+static const u32 aspeed_xdma_bmc_pcie_conf = SCU_PCIE_CONF_BMC_EN |
+ SCU_PCIE_CONF_BMC_EN_MSI | SCU_PCIE_CONF_BMC_EN_MCTP |
+ SCU_PCIE_CONF_BMC_EN_IRQ | SCU_PCIE_CONF_BMC_EN_DMA |
+ SCU_PCIE_CONF_RSVD;
+
+static const u32 aspeed_xdma_vga_pcie_conf = SCU_PCIE_CONF_VGA_EN |
+ SCU_PCIE_CONF_VGA_EN_MSI | SCU_PCIE_CONF_VGA_EN_MCTP |
+ SCU_PCIE_CONF_VGA_EN_IRQ | SCU_PCIE_CONF_VGA_EN_DMA |
+ SCU_PCIE_CONF_RSVD;
+
+static void aspeed_scu_pcie_write(struct aspeed_xdma *ctx, u32 conf)
+{
+ u32 v = 0;
+
+ regmap_write(ctx->scu, SCU_PCIE_CONF, conf);
+ regmap_read(ctx->scu, SCU_PCIE_CONF, &v);
+
+ dev_dbg(ctx->dev, "write scu pcie_conf[%08x]\n", v);
+}
+
+static u32 aspeed_xdma_reg_read(struct aspeed_xdma *ctx, u32 reg)
+{
+ u32 v = readl(ctx->base + reg);
+
+ dev_dbg(ctx->dev, "read %02x[%08x]\n", reg, v);
+ return v;
+}
+
+static void aspeed_xdma_reg_write(struct aspeed_xdma *ctx, u32 reg, u32 val)
+{
+ writel(val, ctx->base + reg);
+ dev_dbg(ctx->dev, "write %02x[%08x]\n", reg, readl(ctx->base + reg));
+}
+
+static void aspeed_xdma_init_eng(struct aspeed_xdma *ctx)
+{
+ const u32 ctrl = XDMA_CTRL_US_COMP | XDMA_CTRL_DS_COMP |
+ XDMA_CTRL_DS_DIRTY | FIELD_PREP(XDMA_CTRL_DS_PCIE_REQ_SIZE,
+ XDMA_DS_PCIE_REQ_SIZE_256) |
+ XDMA_CTRL_DS_DATA_TIMEOUT | XDMA_CTRL_DS_CHECK_ID;
+
+ aspeed_xdma_reg_write(ctx, XDMA_BMC_CMD_QUEUE_ENDP,
+ XDMA_CMD_SIZE * XDMA_NUM_CMDS);
+ aspeed_xdma_reg_write(ctx, XDMA_BMC_CMD_QUEUE_READP,
+ XDMA_BMC_CMD_QUEUE_READP_MAGIC);
+ aspeed_xdma_reg_write(ctx, XDMA_BMC_CMD_QUEUE_WRITEP, 0);
+ aspeed_xdma_reg_write(ctx, XDMA_CTRL, ctrl);
+
+ aspeed_xdma_reg_write(ctx, XDMA_BMC_CMD_QUEUE_ADDR,
+ ctx->cmdq_vga_phys);
+
+ ctx->cmd_idx = 0;
+ ctx->flags = 0;
+}
+
+static void aspeed_xdma_reset(struct aspeed_xdma *ctx)
+{
+ reset_control_assert(ctx->reset);
+
+ msleep(10);
+
+ reset_control_deassert(ctx->reset);
+
+ msleep(10);
+
+ aspeed_xdma_init_eng(ctx);
+}
+
+static void aspeed_xdma_start(struct aspeed_xdma *ctx,
+ struct aspeed_xdma_op *op, u32 bmc_addr)
+{
+ u32 conf = XDMA_CMD_CONF_CHECK | XDMA_CMD_CONF_IRQ_BMC |
+ XDMA_CMD_CONF_IRQ;
+ unsigned int line_size = op->len / XDMA_BYTE_ALIGN;
+ unsigned int num_lines = 1;
+ unsigned int nidx = (ctx->cmd_idx + 1) % XDMA_NUM_CMDS;
+ unsigned int pitch = 1;
+ struct aspeed_xdma_cmd *cmd =
+ &(((struct aspeed_xdma_cmd *)ctx->cmdq)[ctx->cmd_idx]);
+
+ if (line_size > XDMA_MAX_LINE_SIZE) {
+ unsigned int rem;
+ unsigned int total;
+
+ num_lines = line_size / XDMA_MAX_LINE_SIZE;
+ total = XDMA_MAX_LINE_SIZE * num_lines;
+ rem = line_size - total;
+ line_size = XDMA_MAX_LINE_SIZE;
+ pitch = line_size;
+
+ if (rem) {
+ unsigned int offs = total * XDMA_BYTE_ALIGN;
+ u32 r_bmc_addr = bmc_addr + offs;
+ u64 r_host_addr = op->host_addr + (u64)offs;
+ struct aspeed_xdma_cmd *r_cmd =
+ &(((struct aspeed_xdma_cmd *)ctx->cmdq)[nidx]);
+
+ r_cmd->host_addr_lo =
+ (u32)(r_host_addr & 0xFFFFFFFFULL);
+ r_cmd->host_addr_hi = (u32)(r_host_addr >> 32ULL);
+ r_cmd->bmc_addr = (r_bmc_addr & XDMA_CMD_BMC_ADDR) |
+ XDMA_CMD_BMC_CHECK |
+ (op->upstream ? XDMA_CMD_BMC_DIR_US : 0);
+ r_cmd->conf = conf |
+ FIELD_PREP(XDMA_CMD_CONF_LINE_SIZE, rem) |
+ FIELD_PREP(XDMA_CMD_CONF_NUM_LINES, 1);
+ r_cmd->comm1_hi =
+ FIELD_PREP(XDMA_CMD_COMM1_HI_HOST_PITCH, 1) |
+ FIELD_PREP(XDMA_CMD_COMM1_HI_BMC_PITCH, 1);
+
+ /* do not trigger IRQ for first command */
+ conf = XDMA_CMD_CONF_CHECK;
+
+ nidx = (nidx + 1) % XDMA_NUM_CMDS;
+ }
+
+ /* undocumented formula to get required number of lines */
+ num_lines = (num_lines * 2) - 1;
+ }
+
+ /* ctrl == 0 indicates engine hasn't started properly; restart it */
+ if (!aspeed_xdma_reg_read(ctx, XDMA_CTRL))
+ aspeed_xdma_reset(ctx);
+
+ cmd->host_addr_lo = (u32)(op->host_addr & 0xFFFFFFFFULL);
+ cmd->host_addr_hi = (u32)(op->host_addr >> 32ULL);
+ cmd->bmc_addr = (bmc_addr & XDMA_CMD_BMC_ADDR) | XDMA_CMD_BMC_CHECK |
+ (op->upstream ? XDMA_CMD_BMC_DIR_US : 0);
+ cmd->conf = conf |
+ FIELD_PREP(XDMA_CMD_CONF_LINE_SIZE, line_size) |
+ FIELD_PREP(XDMA_CMD_CONF_NUM_LINES, num_lines);
+ cmd->comm1_hi = FIELD_PREP(XDMA_CMD_COMM1_HI_HOST_PITCH, pitch) |
+ FIELD_PREP(XDMA_CMD_COMM1_HI_BMC_PITCH, pitch);
+
+ memcpy(ctx->cmdq_vga_virt, ctx->cmdq, XDMA_CMDQ_SIZE);
+
+ if (op->upstream)
+ set_bit(XDMA_UPSTREAM, &ctx->flags);
+ else
+ clear_bit(XDMA_UPSTREAM, &ctx->flags);
+
+ set_bit(XDMA_IN_PRG, &ctx->flags);
+
+ aspeed_xdma_reg_write(ctx, XDMA_BMC_CMD_QUEUE_WRITEP,
+ nidx * XDMA_CMD_SIZE);
+ ctx->cmd_idx = nidx;
+}
+
+static void aspeed_xdma_done(struct aspeed_xdma *ctx)
+{
+ if (ctx->current_client) {
+ clear_bit(XDMA_IN_PRG, &ctx->current_client->flags);
+
+ ctx->current_client = NULL;
+ }
+
+ clear_bit(XDMA_IN_PRG, &ctx->flags);
+ wake_up_interruptible_all(&ctx->wait);
+}
+
+static irqreturn_t aspeed_xdma_irq(int irq, void *arg)
+{
+ struct aspeed_xdma *ctx = arg;
+ u32 status = aspeed_xdma_reg_read(ctx, XDMA_STATUS);
+
+ if (status & XDMA_STATUS_US_COMP) {
+ if (test_bit(XDMA_UPSTREAM, &ctx->flags))
+ aspeed_xdma_done(ctx);
+ }
+
+ if (status & XDMA_STATUS_DS_COMP) {
+ if (!test_bit(XDMA_UPSTREAM, &ctx->flags))
+ aspeed_xdma_done(ctx);
+ }
+
+ aspeed_xdma_reg_write(ctx, XDMA_STATUS, status);
+
+ return IRQ_HANDLED;
+}
+
+static int aspeed_xdma_init_mem(struct aspeed_xdma *ctx)
+{
+ int rc;
+ u32 scu_conf = 0;
+ u32 mem_size = 0x20000000;
+ const u32 mem_sizes[4] = { 0x8000000, 0x10000000, 0x20000000,
+ 0x40000000 };
+ const u32 vga_sizes[4] = { 0x800000, 0x1000000, 0x2000000, 0x4000000 };
+ void __iomem *sdmc_base = ioremap(0x1e6e0000, 0x100);
+
+ aspeed_scu_pcie_write(ctx, aspeed_xdma_vga_pcie_conf);
+
+ regmap_read(ctx->scu, SCU_STRAP, &scu_conf);
+ ctx->vga_size = vga_sizes[FIELD_GET(SCU_STRAP_VGA_MEM, scu_conf)];
+
+ if (sdmc_base) {
+ u32 sdmc = readl(sdmc_base + SDMC_CONF);
+ u32 remap = readl(sdmc_base + SDMC_REMAP);
+
+ remap |= SDMC_REMAP_MAGIC;
+ writel(remap, sdmc_base + SDMC_REMAP);
+ remap = readl(sdmc_base + SDMC_REMAP);
+
+ mem_size = mem_sizes[sdmc & SDMC_CONF_MEM];
+ iounmap(sdmc_base);
+ }
+
+ ctx->vga_phys = (mem_size - ctx->vga_size) + 0x80000000;
+
+ ctx->cmdq = devm_kzalloc(ctx->dev, XDMA_CMDQ_SIZE, GFP_KERNEL);
+ if (!ctx->cmdq) {
+ dev_err(ctx->dev, "Failed to allocate command queue.\n");
+ return -ENOMEM;
+ }
+
+ rc = dma_set_mask_and_coherent(ctx->dev, DMA_BIT_MASK(32));
+ if (rc) {
+ dev_err(ctx->dev, "Failed to set DMA mask: %d.\n", rc);
+ return rc;
+ }
+
+ rc = dma_declare_coherent_memory(ctx->dev, ctx->vga_phys,
+ ctx->vga_phys, ctx->vga_size);
+ if (rc) {
+ dev_err(ctx->dev, "Failed to declare coherent memory: %d.\n",
+ rc);
+ return rc;
+ }
+
+ ctx->vga_virt = dma_alloc_coherent(ctx->dev, ctx->vga_size,
+ &ctx->vga_dma, GFP_KERNEL);
+ if (!ctx->vga_virt) {
+ dev_err(ctx->dev, "Failed to allocate DMA.\n");
+ rc = -ENOMEM;
+ goto err_dma;
+ }
+
+ rc = gen_pool_add_virt(ctx->vga_pool, (unsigned long)ctx->vga_virt,
+ ctx->vga_phys, ctx->vga_size, -1);
+ if (rc) {
+ dev_err(ctx->dev, "Failed to add memory to genalloc pool.\n");
+ goto err_genalloc;
+ }
+
+ ctx->cmdq_vga_virt = gen_pool_dma_alloc(ctx->vga_pool, XDMA_CMDQ_SIZE,
+ &ctx->cmdq_vga_phys);
+ if (!ctx->cmdq_vga_virt) {
+ dev_err(ctx->dev, "Failed to genalloc cmdq.\n");
+ rc = -ENOMEM;
+ goto err_genalloc;
+ }
+
+ dev_dbg(ctx->dev, "VGA mapped at phys[%08x], size[%08x].\n",
+ ctx->vga_phys, ctx->vga_size);
+
+ return 0;
+
+err_dma:
+ dma_release_declared_memory(ctx->dev);
+
+err_genalloc:
+ dma_free_coherent(ctx->dev, ctx->vga_size, ctx->vga_virt,
+ ctx->vga_dma);
+ return rc;
+}
+
+static int aspeed_xdma_probe(struct platform_device *pdev)
+{
+ int irq;
+ int rc;
+ struct resource *res;
+ struct device *dev = &pdev->dev;
+ struct aspeed_xdma *ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+
+ if (!ctx)
+ return -ENOMEM;
+
+ ctx->dev = dev;
+ platform_set_drvdata(pdev, ctx);
+ init_waitqueue_head(&ctx->wait);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ ctx->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(ctx->base)) {
+ dev_err(dev, "Unable to ioremap registers.\n");
+ return PTR_ERR(ctx->base);
+ }
+
+ irq = irq_of_parse_and_map(dev->of_node, 0);
+ if (!irq) {
+ dev_err(dev, "Unable to find IRQ.\n");
+ return -ENODEV;
+ }
+
+ rc = devm_request_irq(dev, irq, aspeed_xdma_irq, IRQF_SHARED,
+ DEVICE_NAME, ctx);
+ if (rc < 0) {
+ dev_err(dev, "Unable to request IRQ %d.\n", irq);
+ return rc;
+ }
+
+ ctx->scu = syscon_regmap_lookup_by_compatible("aspeed,ast2500-scu");
+ if (IS_ERR(ctx->scu)) {
+ dev_err(ctx->dev, "Unable to grab SCU regs.\n");
+ return PTR_ERR(ctx->scu);
+ }
+
+ ctx->reset = devm_reset_control_get_exclusive(dev, NULL);
+ if (IS_ERR(ctx->reset)) {
+ dev_err(dev, "Unable to request reset control.\n");
+ return PTR_ERR(ctx->reset);
+ }
+
+ ctx->vga_pool = devm_gen_pool_create(dev, ilog2(PAGE_SIZE), -1, NULL);
+ if (!ctx->vga_pool) {
+ dev_err(dev, "Unable to setup genalloc pool.\n");
+ return -ENOMEM;
+ }
+
+ reset_control_deassert(ctx->reset);
+
+ msleep(10);
+
+ rc = aspeed_xdma_init_mem(ctx);
+ if (rc) {
+ reset_control_assert(ctx->reset);
+ return rc;
+ }
+
+ aspeed_xdma_init_eng(ctx);
+
+ return 0;
+}
+
+static int aspeed_xdma_remove(struct platform_device *pdev)
+{
+ struct aspeed_xdma *ctx = platform_get_drvdata(pdev);
+
+ gen_pool_free(ctx->vga_pool, (unsigned long)ctx->cmdq_vga_virt,
+ XDMA_CMDQ_SIZE);
+ dma_free_coherent(ctx->dev, ctx->vga_size, ctx->vga_virt,
+ ctx->vga_dma);
+ dma_release_declared_memory(ctx->dev);
+ reset_control_assert(ctx->reset);
+
+ return 0;
+}
+
+static const struct of_device_id aspeed_xdma_match[] = {
+ { .compatible = "aspeed,ast2500-xdma" },
+ { },
+};
+
+static struct platform_driver aspeed_xdma_driver = {
+ .probe = aspeed_xdma_probe,
+ .remove = aspeed_xdma_remove,
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = aspeed_xdma_match,
+ },
+};
+
+module_platform_driver(aspeed_xdma_driver);
+
+MODULE_AUTHOR("Eddie James");
+MODULE_DESCRIPTION("Aspeed XDMA Engine Driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/uapi/linux/aspeed-xdma.h b/include/uapi/linux/aspeed-xdma.h
new file mode 100644
index 0000000..998459e
--- /dev/null
+++ b/include/uapi/linux/aspeed-xdma.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/* Copyright IBM Corp 2019 */
+
+#ifndef _UAPI_LINUX_ASPEED_XDMA_H_
+#define _UAPI_LINUX_ASPEED_XDMA_H_
+
+#include <linux/types.h>
+
+/*
+ * aspeed_xdma_op
+ *
+ * host_addr: the DMA address on the host side, typically configured by PCI
+ * subsystem
+ *
+ * len: the size of the transfer in bytes; it should be a multiple of 16 bytes
+ *
+ * upstream: boolean indicating the direction of the DMA operation; upstream
+ * means a transfer from the BMC to the host
+ */
+struct aspeed_xdma_op {
+ __u64 host_addr;
+ __u32 len;
+ __u32 upstream;
+};
+
+#endif /* _UAPI_LINUX_ASPEED_XDMA_H_ */
--
1.8.3.1