[PATCH 2/4] soc: aspeed: Add UART DMA support
From: Chia-Wei Wang
Date: Fri Feb 10 2023 - 02:28:05 EST
This driver provides DMA support for AST26xx UART and VUART
devices. It is useful to offload CPU overhead while using
UART/VUART for binary file transfer.
Signed-off-by: Chia-Wei Wang <chiawei_wang@xxxxxxxxxxxxxx>
---
drivers/soc/aspeed/Kconfig | 9 +
drivers/soc/aspeed/Makefile | 1 +
drivers/soc/aspeed/aspeed-udma.c | 447 +++++++++++++++++++++++++
include/linux/soc/aspeed/aspeed-udma.h | 34 ++
4 files changed, 491 insertions(+)
create mode 100644 drivers/soc/aspeed/aspeed-udma.c
create mode 100644 include/linux/soc/aspeed/aspeed-udma.h
diff --git a/drivers/soc/aspeed/Kconfig b/drivers/soc/aspeed/Kconfig
index f579ee0b5afa..c3bb238bea75 100644
--- a/drivers/soc/aspeed/Kconfig
+++ b/drivers/soc/aspeed/Kconfig
@@ -52,6 +52,15 @@ config ASPEED_SOCINFO
help
Say yes to support decoding of ASPEED BMC information.
+config ASPEED_UDMA
+ tristate "Aspeed UDMA Engine Driver"
+ default ARCH_ASPEED
+ help
+ Enable support for the Aspeed UDMA Engine found on the
+ Aspeed AST26xx SOCs. The UDMA engine provides UART DMA
+ operations between the memory buffer and UART/VUART
+ FIFO data.
+
endmenu
endif
diff --git a/drivers/soc/aspeed/Makefile b/drivers/soc/aspeed/Makefile
index b35d74592964..5aeabafee1d4 100644
--- a/drivers/soc/aspeed/Makefile
+++ b/drivers/soc/aspeed/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_ASPEED_LPC_SNOOP) += aspeed-lpc-snoop.o
obj-$(CONFIG_ASPEED_UART_ROUTING) += aspeed-uart-routing.o
obj-$(CONFIG_ASPEED_P2A_CTRL) += aspeed-p2a-ctrl.o
obj-$(CONFIG_ASPEED_SOCINFO) += aspeed-socinfo.o
+obj-$(CONFIG_ASPEED_UDMA) += aspeed-udma.o
diff --git a/drivers/soc/aspeed/aspeed-udma.c b/drivers/soc/aspeed/aspeed-udma.c
new file mode 100644
index 000000000000..95898fbd6ed8
--- /dev/null
+++ b/drivers/soc/aspeed/aspeed-udma.c
@@ -0,0 +1,447 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) Aspeed Technology Inc.
+ */
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/spinlock.h>
+#include <linux/soc/aspeed/aspeed-udma.h>
+#include <linux/delay.h>
+
+#define DEVICE_NAME "aspeed-udma"
+
+/* UART DMA registers offset */
+#define UDMA_TX_DMA_EN 0x000
+#define UDMA_RX_DMA_EN 0x004
+#define UDMA_TIMEOUT_TIMER 0x00c
+#define UDMA_TX_DMA_RST 0x020
+#define UDMA_RX_DMA_RST 0x024
+#define UDMA_TX_DMA_INT_EN 0x030
+#define UDMA_TX_DMA_INT_STAT 0x034
+#define UDMA_RX_DMA_INT_EN 0x038
+#define UDMA_RX_DMA_INT_STAT 0x03c
+
+#define UDMA_CHX_OFF(x) ((x) * 0x20)
+#define UDMA_CHX_TX_RD_PTR(x) (0x040 + UDMA_CHX_OFF(x))
+#define UDMA_CHX_TX_WR_PTR(x) (0x044 + UDMA_CHX_OFF(x))
+#define UDMA_CHX_TX_BUF_BASE(x) (0x048 + UDMA_CHX_OFF(x))
+#define UDMA_CHX_TX_CTRL(x) (0x04c + UDMA_CHX_OFF(x))
+#define UDMA_TX_CTRL_TMOUT_DISABLE BIT(4)
+#define UDMA_TX_CTRL_BUFSZ_MASK GENMASK(3, 0)
+#define UDMA_TX_CTRL_BUFSZ_SHIFT 0
+#define UDMA_CHX_RX_RD_PTR(x) (0x050 + UDMA_CHX_OFF(x))
+#define UDMA_CHX_RX_WR_PTR(x) (0x054 + UDMA_CHX_OFF(x))
+#define UDMA_CHX_RX_BUF_BASE(x) (0x058 + UDMA_CHX_OFF(x))
+#define UDMA_CHX_RX_CTRL(x) (0x05c + UDMA_CHX_OFF(x))
+#define UDMA_RX_CTRL_TMOUT_DISABLE BIT(4)
+#define UDMA_RX_CTRL_BUFSZ_MASK GENMASK(3, 0)
+#define UDMA_RX_CTRL_BUFSZ_SHIFT 0
+
+#define UDMA_MAX_CHANNEL 14
+#define UDMA_TIMEOUT 0x200
+
+enum aspeed_udma_bufsz_code {
+ UDMA_BUFSZ_CODE_1KB,
+ UDMA_BUFSZ_CODE_4KB,
+ UDMA_BUFSZ_CODE_16KB,
+ UDMA_BUFSZ_CODE_64KB,
+
+ /*
+ * 128KB and above are supported ONLY for
+ * virtual UARTs. For physical UARTs, the
+ * size code is wrapped around at the 64K
+ * boundary.
+ */
+ UDMA_BUFSZ_CODE_128KB,
+ UDMA_BUFSZ_CODE_256KB,
+ UDMA_BUFSZ_CODE_512KB,
+ UDMA_BUFSZ_CODE_1024KB,
+ UDMA_BUFSZ_CODE_2048KB,
+ UDMA_BUFSZ_CODE_4096KB,
+ UDMA_BUFSZ_CODE_8192KB,
+ UDMA_BUFSZ_CODE_16384KB,
+};
+
+struct aspeed_udma_chan {
+ dma_addr_t dma_addr;
+
+ struct circ_buf *rb;
+ u32 rb_sz;
+
+ aspeed_udma_cb_t cb;
+ void *cb_arg;
+
+ bool dis_tmout;
+};
+
+struct aspeed_udma {
+ struct device *dev;
+ u8 __iomem *regs;
+ int irq;
+ struct aspeed_udma_chan tx_chs[UDMA_MAX_CHANNEL];
+ struct aspeed_udma_chan rx_chs[UDMA_MAX_CHANNEL];
+ spinlock_t lock;
+};
+
+struct aspeed_udma udma[1];
+
+static int aspeed_udma_get_bufsz_code(u32 buf_sz)
+{
+ switch (buf_sz) {
+ case 0x400:
+ return UDMA_BUFSZ_CODE_1KB;
+ case 0x1000:
+ return UDMA_BUFSZ_CODE_4KB;
+ case 0x4000:
+ return UDMA_BUFSZ_CODE_16KB;
+ case 0x10000:
+ return UDMA_BUFSZ_CODE_64KB;
+ case 0x20000:
+ return UDMA_BUFSZ_CODE_128KB;
+ case 0x40000:
+ return UDMA_BUFSZ_CODE_256KB;
+ case 0x80000:
+ return UDMA_BUFSZ_CODE_512KB;
+ case 0x100000:
+ return UDMA_BUFSZ_CODE_1024KB;
+ case 0x200000:
+ return UDMA_BUFSZ_CODE_2048KB;
+ case 0x400000:
+ return UDMA_BUFSZ_CODE_4096KB;
+ case 0x800000:
+ return UDMA_BUFSZ_CODE_8192KB;
+ case 0x1000000:
+ return UDMA_BUFSZ_CODE_16384KB;
+ default:
+ return -1;
+ }
+
+ return -1;
+}
+
+static u32 aspeed_udma_get_tx_rptr(u32 ch_no)
+{
+ return readl(udma->regs + UDMA_CHX_TX_RD_PTR(ch_no));
+}
+
+static u32 aspeed_udma_get_rx_wptr(u32 ch_no)
+{
+ return readl(udma->regs + UDMA_CHX_RX_WR_PTR(ch_no));
+}
+
+static void aspeed_udma_set_ptr(u32 ch_no, u32 ptr, bool is_tx)
+{
+ writel(ptr, udma->regs +
+ ((is_tx) ? UDMA_CHX_TX_WR_PTR(ch_no) : UDMA_CHX_RX_RD_PTR(ch_no)));
+}
+
+void aspeed_udma_set_tx_wptr(u32 ch_no, u32 wptr)
+{
+ aspeed_udma_set_ptr(ch_no, wptr, true);
+}
+EXPORT_SYMBOL(aspeed_udma_set_tx_wptr);
+
+void aspeed_udma_set_rx_rptr(u32 ch_no, u32 rptr)
+{
+ aspeed_udma_set_ptr(ch_no, rptr, false);
+}
+EXPORT_SYMBOL(aspeed_udma_set_rx_rptr);
+
+static int aspeed_udma_free_chan(u32 ch_no, bool is_tx)
+{
+ u32 reg;
+ unsigned long flags;
+
+ if (ch_no > UDMA_MAX_CHANNEL)
+ return -EINVAL;
+
+ spin_lock_irqsave(&udma->lock, flags);
+
+ reg = readl(udma->regs +
+ ((is_tx) ? UDMA_TX_DMA_INT_EN : UDMA_RX_DMA_INT_EN));
+ reg &= ~(0x1 << ch_no);
+
+ writel(reg, udma->regs +
+ ((is_tx) ? UDMA_TX_DMA_INT_EN : UDMA_RX_DMA_INT_EN));
+
+ spin_unlock_irqrestore(&udma->lock, flags);
+
+ return 0;
+}
+
+int aspeed_udma_free_tx_chan(u32 ch_no)
+{
+ return aspeed_udma_free_chan(ch_no, true);
+}
+EXPORT_SYMBOL(aspeed_udma_free_tx_chan);
+
+int aspeed_udma_free_rx_chan(u32 ch_no)
+{
+ return aspeed_udma_free_chan(ch_no, false);
+}
+EXPORT_SYMBOL(aspeed_udma_free_rx_chan);
+
+static int aspeed_udma_request_chan(u32 ch_no, dma_addr_t addr,
+ struct circ_buf *rb, u32 rb_sz,
+ aspeed_udma_cb_t cb, void *id, bool dis_tmout, bool is_tx)
+{
+ int retval = 0;
+ int rbsz_code;
+
+ u32 reg;
+ unsigned long flags;
+ struct aspeed_udma_chan *ch;
+
+ if (ch_no > UDMA_MAX_CHANNEL) {
+ retval = -EINVAL;
+ goto out;
+ }
+
+ if (IS_ERR_OR_NULL(rb) || IS_ERR_OR_NULL(rb->buf)) {
+ retval = -EINVAL;
+ goto out;
+ }
+
+ rbsz_code = aspeed_udma_get_bufsz_code(rb_sz);
+ if (rbsz_code < 0) {
+ retval = -EINVAL;
+ goto out;
+ }
+
+ spin_lock_irqsave(&udma->lock, flags);
+
+ if (is_tx) {
+ reg = readl(udma->regs + UDMA_TX_DMA_INT_EN);
+ if (reg & (0x1 << ch_no)) {
+ retval = -EBUSY;
+ goto unlock_n_out;
+ }
+
+ reg |= (0x1 << ch_no);
+ writel(reg, udma->regs + UDMA_TX_DMA_INT_EN);
+
+ reg = readl(udma->regs + UDMA_CHX_TX_CTRL(ch_no));
+ reg |= (dis_tmout) ? UDMA_TX_CTRL_TMOUT_DISABLE : 0;
+ reg |= (rbsz_code << UDMA_TX_CTRL_BUFSZ_SHIFT) & UDMA_TX_CTRL_BUFSZ_MASK;
+ writel(reg, udma->regs + UDMA_CHX_TX_CTRL(ch_no));
+
+ writel(addr, udma->regs + UDMA_CHX_TX_BUF_BASE(ch_no));
+ } else {
+ reg = readl(udma->regs + UDMA_RX_DMA_INT_EN);
+ if (reg & (0x1 << ch_no)) {
+ retval = -EBUSY;
+ goto unlock_n_out;
+ }
+
+ reg |= (0x1 << ch_no);
+ writel(reg, udma->regs + UDMA_RX_DMA_INT_EN);
+
+ reg = readl(udma->regs + UDMA_CHX_RX_CTRL(ch_no));
+ reg |= (dis_tmout) ? UDMA_RX_CTRL_TMOUT_DISABLE : 0;
+ reg |= (rbsz_code << UDMA_RX_CTRL_BUFSZ_SHIFT) & UDMA_RX_CTRL_BUFSZ_MASK;
+ writel(reg, udma->regs + UDMA_CHX_RX_CTRL(ch_no));
+
+ writel(addr, udma->regs + UDMA_CHX_RX_BUF_BASE(ch_no));
+ }
+
+ ch = (is_tx) ? &udma->tx_chs[ch_no] : &udma->rx_chs[ch_no];
+ ch->rb = rb;
+ ch->rb_sz = rb_sz;
+ ch->cb = cb;
+ ch->cb_arg = id;
+ ch->dma_addr = addr;
+ ch->dis_tmout = dis_tmout;
+
+unlock_n_out:
+ spin_unlock_irqrestore(&udma->lock, flags);
+out:
+ return 0;
+}
+
+int aspeed_udma_request_tx_chan(u32 ch_no, dma_addr_t addr,
+ struct circ_buf *rb, u32 rb_sz,
+ aspeed_udma_cb_t cb, void *id, bool dis_tmout)
+{
+ return aspeed_udma_request_chan(ch_no, addr, rb, rb_sz, cb, id,
+ dis_tmout, true);
+}
+EXPORT_SYMBOL(aspeed_udma_request_tx_chan);
+
+int aspeed_udma_request_rx_chan(u32 ch_no, dma_addr_t addr,
+ struct circ_buf *rb, u32 rb_sz,
+ aspeed_udma_cb_t cb, void *id, bool dis_tmout)
+{
+ return aspeed_udma_request_chan(ch_no, addr, rb, rb_sz, cb, id,
+ dis_tmout, false);
+}
+EXPORT_SYMBOL(aspeed_udma_request_rx_chan);
+
+static void aspeed_udma_chan_ctrl(u32 ch_no, u32 op, bool is_tx)
+{
+ unsigned long flags;
+ u32 reg_en, reg_rst;
+ u32 reg_en_off = (is_tx) ? UDMA_TX_DMA_EN : UDMA_RX_DMA_EN;
+ u32 reg_rst_off = (is_tx) ? UDMA_TX_DMA_RST : UDMA_TX_DMA_RST;
+
+ if (ch_no > UDMA_MAX_CHANNEL)
+ return;
+
+ spin_lock_irqsave(&udma->lock, flags);
+
+ reg_en = readl(udma->regs + reg_en_off);
+ reg_rst = readl(udma->regs + reg_rst_off);
+
+ switch (op) {
+ case ASPEED_UDMA_OP_ENABLE:
+ reg_en |= (0x1 << ch_no);
+ writel(reg_en, udma->regs + reg_en_off);
+ break;
+ case ASPEED_UDMA_OP_DISABLE:
+ reg_en &= ~(0x1 << ch_no);
+ writel(reg_en, udma->regs + reg_en_off);
+ break;
+ case ASPEED_UDMA_OP_RESET:
+ reg_en &= ~(0x1 << ch_no);
+ writel(reg_en, udma->regs + reg_en_off);
+
+ reg_rst |= (0x1 << ch_no);
+ writel(reg_rst, udma->regs + reg_rst_off);
+
+ udelay(100);
+
+ reg_rst &= ~(0x1 << ch_no);
+ writel(reg_rst, udma->regs + reg_rst_off);
+ break;
+ default:
+ break;
+ }
+
+ spin_unlock_irqrestore(&udma->lock, flags);
+}
+
+void aspeed_udma_tx_chan_ctrl(u32 ch_no, enum aspeed_udma_ops op)
+{
+ aspeed_udma_chan_ctrl(ch_no, op, true);
+}
+EXPORT_SYMBOL(aspeed_udma_tx_chan_ctrl);
+
+void aspeed_udma_rx_chan_ctrl(u32 ch_no, enum aspeed_udma_ops op)
+{
+ aspeed_udma_chan_ctrl(ch_no, op, false);
+}
+EXPORT_SYMBOL(aspeed_udma_rx_chan_ctrl);
+
+static irqreturn_t aspeed_udma_isr(int irq, void *arg)
+{
+ u32 bit;
+ unsigned long tx_stat = readl(udma->regs + UDMA_TX_DMA_INT_STAT);
+ unsigned long rx_stat = readl(udma->regs + UDMA_RX_DMA_INT_STAT);
+
+ if (udma != (struct aspeed_udma *)arg)
+ return IRQ_NONE;
+
+ if (tx_stat == 0 && rx_stat == 0)
+ return IRQ_NONE;
+
+ for_each_set_bit(bit, &tx_stat, UDMA_MAX_CHANNEL) {
+ writel((0x1 << bit), udma->regs + UDMA_TX_DMA_INT_STAT);
+ if (udma->tx_chs[bit].cb)
+ udma->tx_chs[bit].cb(aspeed_udma_get_tx_rptr(bit),
+ udma->tx_chs[bit].cb_arg);
+ }
+
+ for_each_set_bit(bit, &rx_stat, UDMA_MAX_CHANNEL) {
+ writel((0x1 << bit), udma->regs + UDMA_RX_DMA_INT_STAT);
+ if (udma->rx_chs[bit].cb)
+ udma->rx_chs[bit].cb(aspeed_udma_get_rx_wptr(bit),
+ udma->rx_chs[bit].cb_arg);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int aspeed_udma_probe(struct platform_device *pdev)
+{
+ int i, rc;
+ struct resource *res;
+ struct device *dev = &pdev->dev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (IS_ERR_OR_NULL(res)) {
+ dev_err(dev, "failed to get register base\n");
+ return -ENODEV;
+ }
+
+ udma->regs = devm_ioremap_resource(dev, res);
+ if (IS_ERR_OR_NULL(udma->regs)) {
+ dev_err(dev, "failed to map registers\n");
+ return PTR_ERR(udma->regs);
+ }
+
+ /* disable for safety */
+ writel(0x0, udma->regs + UDMA_TX_DMA_EN);
+ writel(0x0, udma->regs + UDMA_RX_DMA_EN);
+
+ udma->irq = platform_get_irq(pdev, 0);
+ if (udma->irq < 0) {
+ dev_err(dev, "failed to get IRQ number\n");
+ return -ENODEV;
+ }
+
+ rc = devm_request_irq(dev, udma->irq, aspeed_udma_isr,
+ IRQF_SHARED, DEVICE_NAME, udma);
+ if (rc) {
+ dev_err(dev, "failed to request IRQ handler\n");
+ return rc;
+ }
+
+ for (i = 0; i < UDMA_MAX_CHANNEL; ++i) {
+ writel(0, udma->regs + UDMA_CHX_TX_WR_PTR(i));
+ writel(0, udma->regs + UDMA_CHX_RX_RD_PTR(i));
+ }
+
+ writel(0xffffffff, udma->regs + UDMA_TX_DMA_RST);
+ writel(0x0, udma->regs + UDMA_TX_DMA_RST);
+
+ writel(0xffffffff, udma->regs + UDMA_RX_DMA_RST);
+ writel(0x0, udma->regs + UDMA_RX_DMA_RST);
+
+ writel(0x0, udma->regs + UDMA_TX_DMA_INT_EN);
+ writel(0xffffffff, udma->regs + UDMA_TX_DMA_INT_STAT);
+ writel(0x0, udma->regs + UDMA_RX_DMA_INT_EN);
+ writel(0xffffffff, udma->regs + UDMA_RX_DMA_INT_STAT);
+
+ writel(UDMA_TIMEOUT, udma->regs + UDMA_TIMEOUT_TIMER);
+
+ spin_lock_init(&udma->lock);
+
+ dev_set_drvdata(dev, udma);
+
+ return 0;
+}
+
+static const struct of_device_id aspeed_udma_match[] = {
+ { .compatible = "aspeed,ast2600-udma" },
+ { },
+};
+
+static struct platform_driver aspeed_udma_driver = {
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = aspeed_udma_match,
+
+ },
+ .probe = aspeed_udma_probe,
+};
+
+module_platform_driver(aspeed_udma_driver);
+
+MODULE_AUTHOR("Chia-Wei Wang <chiawei_wang@xxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Aspeed UDMA Engine Driver");
diff --git a/include/linux/soc/aspeed/aspeed-udma.h b/include/linux/soc/aspeed/aspeed-udma.h
new file mode 100644
index 000000000000..4ec95d726ede
--- /dev/null
+++ b/include/linux/soc/aspeed/aspeed-udma.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) Aspeed Technology Inc.
+ */
+#ifndef __ASPEED_UDMA_H__
+#define __ASPEED_UDMA_H__
+
+#include <linux/circ_buf.h>
+
+typedef void (*aspeed_udma_cb_t)(int rb_rwptr, void *id);
+
+enum aspeed_udma_ops {
+ ASPEED_UDMA_OP_ENABLE,
+ ASPEED_UDMA_OP_DISABLE,
+ ASPEED_UDMA_OP_RESET,
+};
+
+void aspeed_udma_set_tx_wptr(u32 ch_no, u32 wptr);
+void aspeed_udma_set_rx_rptr(u32 ch_no, u32 rptr);
+
+void aspeed_udma_tx_chan_ctrl(u32 ch_no, enum aspeed_udma_ops op);
+void aspeed_udma_rx_chan_ctrl(u32 ch_no, enum aspeed_udma_ops op);
+
+int aspeed_udma_request_tx_chan(u32 ch_no, dma_addr_t addr,
+ struct circ_buf *rb, u32 rb_sz,
+ aspeed_udma_cb_t cb, void *id, bool en_tmout);
+int aspeed_udma_request_rx_chan(u32 ch_no, dma_addr_t addr,
+ struct circ_buf *rb, u32 rb_sz,
+ aspeed_udma_cb_t cb, void *id, bool en_tmout);
+
+int aspeed_udma_free_tx_chan(u32 ch_no);
+int aspeed_udma_free_rx_chan(u32 ch_no);
+
+#endif
--
2.25.1