[PATCH v3 3/5] dmaengine: aspeed: Add AST2600 UART DMA driver
Chia-Wei Wang
chiawei_wang at aspeedtech.com
Mon Mar 20 01:11:31 PDT 2023
Aspeed AST2600 UART DMA (UDMA) includes 28 channels for the
DMA transmission and recevie of each UART devices.
Signed-off-by: Chia-Wei Wang <chiawei_wang at aspeedtech.com>
---
drivers/dma/Kconfig | 9 +
drivers/dma/Makefile | 1 +
drivers/dma/ast2600-udma.c | 534 +++++++++++++++++++++++++++++++++++++
3 files changed, 544 insertions(+)
create mode 100644 drivers/dma/ast2600-udma.c
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index fb7073fc034f..18bf6b1350d3 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -93,6 +93,15 @@ config APPLE_ADMAC
help
Enable support for Audio DMA Controller found on Apple Silicon SoCs.
+config ASPEED_AST2600_UDMA
+ bool "Aspeed AST2600 UDMA support"
+ depends on ARCH_ASPEED || COMPILE_TEST
+ help
+ Enable support for Aspeed AST2600 UART DMA. Select this option if you
+ have a AST2600 SoC integrated system. The driver provides the UART DMA
+ support with the dmaengine subsystem, which can be leveraged by generic
+ 8250 serial drivers.
+
config AT_HDMAC
tristate "Atmel AHB DMA support"
depends on ARCH_AT91
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index a4fd1ce29510..6cbacebcdcab 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -81,6 +81,7 @@ obj-$(CONFIG_XGENE_DMA) += xgene-dma.o
obj-$(CONFIG_ST_FDMA) += st_fdma.o
obj-$(CONFIG_FSL_DPAA2_QDMA) += fsl-dpaa2-qdma/
obj-$(CONFIG_INTEL_LDMA) += lgm/
+obj-$(CONFIG_ASPEED_AST2600_UDMA) += ast2600-udma.o
obj-y += mediatek/
obj-y += qcom/
diff --git a/drivers/dma/ast2600-udma.c b/drivers/dma/ast2600-udma.c
new file mode 100644
index 000000000000..39117b26996d
--- /dev/null
+++ b/drivers/dma/ast2600-udma.c
@@ -0,0 +1,534 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) ASPEED Technology Inc.
+ */
+#include <linux/delay.h>
+#include <linux/bitfield.h>
+#include <linux/interrupt.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_dma.h>
+#include <linux/dma-direct.h>
+#include "dmaengine.h"
+
+#define DEVICE_NAME "aspeed-udma"
+
+/* register offset */
+#define UDMA_TX_EN 0x000
+#define UDMA_RX_EN 0x004
+#define UDMA_TMOUT 0x00c
+#define UDMA_TX_PTR_RST 0x020
+#define UDMA_RX_PTR_RST 0x024
+#define UDMA_TX_INT_EN 0x030
+#define UDMA_TX_INT_STS 0x034
+#define UDMA_RX_INT_EN 0x038
+#define UDMA_RX_INT_STS 0x03c
+
+#define UDMA_CH_OFFS(x) ((x) * 0x10)
+#define UDMA_CH_RPTR(x) (0x040 + UDMA_CH_OFFS(x))
+#define UDMA_CH_WPTR(x) (0x044 + UDMA_CH_OFFS(x))
+#define UDMA_CH_ADDR(x) (0x048 + UDMA_CH_OFFS(x))
+#define UDMA_CH_CTRL(x) (0x04c + UDMA_CH_OFFS(x))
+#define UDMA_CH_CTRL_BUFSZ GENMASK(1, 0)
+
+#define UDMA_MAX_BUFSZ (0x10000)
+#define UDMA_MAX_TXSZ (UDMA_MAX_BUFSZ - 1)
+
+enum ast2600_udma_bufsz {
+ UDMA_BUFSZ_1KB,
+ UDMA_BUFSZ_4KB,
+ UDMA_BUFSZ_16KB,
+ UDMA_BUFSZ_64KB,
+};
+
+struct ast2600_udma_desc {
+ struct dma_async_tx_descriptor tx;
+ dma_addr_t addr;
+ unsigned int size;
+};
+
+struct ast2600_udma_chan {
+ struct dma_chan chan;
+ struct ast2600_udma_desc ud;
+ struct ast2600_udma *udma;
+ uint32_t residue;
+
+ /* 4B-aligned local buffer for workaround */
+ uint8_t *buf;
+ dma_addr_t buf_addr;
+
+ bool is_tx;
+};
+
+struct ast2600_udma {
+ struct dma_device ddev;
+ uint8_t __iomem *regs;
+ int irq;
+ struct ast2600_udma_chan *ucs;
+ uint32_t n_ucs;
+ spinlock_t lock;
+};
+
+static struct ast2600_udma_chan *to_ast2600_udma_chan(struct dma_chan *chan)
+{
+ return container_of(chan, struct ast2600_udma_chan, chan);
+}
+
+static int ast2600_udma_alloc_chan_resources(struct dma_chan *chan)
+{
+ dma_cookie_init(chan);
+
+ return 0;
+}
+
+static dma_cookie_t ast2600_udma_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+ return dma_cookie_assign(tx);
+}
+
+/* consider only 8250_dma using dmaengine_prep_slave_single() */
+static struct dma_async_tx_descriptor *ast2600_udma_prep_slave_sg(struct dma_chan *chan,
+ struct scatterlist *sgl,
+ unsigned int sg_len,
+ enum dma_transfer_direction dir,
+ unsigned long tx_flags,
+ void *context)
+{
+ struct device *dev = chan->device->dev;
+ struct ast2600_udma_chan *uc = to_ast2600_udma_chan(chan);
+ struct ast2600_udma_desc *ud = &uc->ud;
+ phys_addr_t pa;
+ void *va;
+
+ if (!is_slave_direction(dir)) {
+ dev_err(dev, "direction is not slave mode\n");
+ return NULL;
+ }
+
+ if (sg_len != 1) {
+ dev_err(dev, "scatter list length is not 1\n");
+ return NULL;
+ }
+
+ if (uc->is_tx && dir != DMA_MEM_TO_DEV) {
+ dev_err(dev, "invalid direction to TX channel\n");
+ return NULL;
+ }
+
+ ud->addr = sg_dma_address(sgl);
+ ud->size = sg_dma_len(sgl);
+
+ if (uc->is_tx) {
+ if (ud->size > UDMA_MAX_TXSZ) {
+ dev_err(dev, "invalid TX DMA SIZE");
+ return NULL;
+ }
+
+ /*
+ * UDMA is limited to 4B-aligned DMA addresses.
+ * Thus copy data to local 4B-aligned buffer if
+ * the source does not fit.
+ */
+ if (ud->addr & 0x3) {
+ pa = dma_to_phys(chan->device->dev, ud->addr);
+ if (pa != (phys_addr_t)-1) {
+ va = phys_to_virt(pa);
+ memcpy(uc->buf, va, ud->size);
+ ud->addr = uc->buf_addr;
+ }
+ }
+ } else {
+ /*
+ * UDMA RX buffer size is limited to 1/4/16/64 KB
+ * We use the lower bits to encode the buffer size
+ */
+ switch (ud->size) {
+ case 0x400:
+ ud->size |= FIELD_PREP(UDMA_CH_CTRL_BUFSZ, UDMA_BUFSZ_1KB);
+ break;
+ case 0x1000:
+ ud->size |= FIELD_PREP(UDMA_CH_CTRL_BUFSZ, UDMA_BUFSZ_4KB);
+ break;
+ case 0x4000:
+ ud->size |= FIELD_PREP(UDMA_CH_CTRL_BUFSZ, UDMA_BUFSZ_16KB);
+ break;
+ case 0x10000:
+ ud->size |= FIELD_PREP(UDMA_CH_CTRL_BUFSZ, UDMA_BUFSZ_64KB);
+ break;
+ default:
+ dev_err(dev, "invalid RX DMA size\n");
+ return NULL;
+ }
+ }
+
+ dma_async_tx_descriptor_init(&ud->tx, &uc->chan);
+ ud->tx.tx_submit = ast2600_udma_tx_submit;
+
+ return &ud->tx;
+}
+
+static void ast2600_udma_issue_pending(struct dma_chan *chan)
+{
+ unsigned long flags;
+ uint32_t r_pr, r_is, r_ie, r_en, reg;
+ uint32_t ch_id = chan->chan_id;
+ uint32_t ch_bit = ch_id / 2;
+ dma_addr_t rx_addr;
+ uint32_t rx_size;
+ struct ast2600_udma_chan *uc = to_ast2600_udma_chan(chan);
+ struct ast2600_udma_desc *ud = &uc->ud;
+ struct ast2600_udma *udma = uc->udma;
+
+ if (uc->is_tx) {
+ r_pr = UDMA_TX_PTR_RST;
+ r_is = UDMA_TX_INT_STS;
+ r_ie = UDMA_TX_INT_EN;
+ r_en = UDMA_TX_EN;
+ } else {
+ r_pr = UDMA_RX_PTR_RST;
+ r_is = UDMA_RX_INT_STS;
+ r_ie = UDMA_RX_INT_EN;
+ r_en = UDMA_RX_EN;
+ }
+
+ spin_lock_irqsave(&udma->lock, flags);
+
+ /* reset channel HW read/write pointer */
+ writel(BIT(ch_bit), udma->regs + r_pr);
+ writel(0, udma->regs + r_pr);
+
+ /* clear interrupt status */
+ writel(BIT(ch_bit), udma->regs + r_is);
+
+ /* set transfer address & size */
+ if (uc->is_tx) {
+ writel(ud->addr, udma->regs + UDMA_CH_ADDR(ch_id));
+ writel(ud->size, udma->regs + UDMA_CH_WPTR(ch_id));
+ writel(UDMA_BUFSZ_64KB, udma->regs + UDMA_CH_CTRL(ch_id));
+ } else {
+ /*
+ * UDMA is limited to 4B-aligned addresses.
+ * Thus use local 4B-aligned buffer to get
+ * RX data and copy to the real destination
+ * after then.
+ */
+ rx_addr = (ud->addr & 0x3) ? uc->buf_addr : ud->addr;
+ rx_size = FIELD_GET(UDMA_CH_CTRL_BUFSZ, ud->size);
+ writel(rx_addr, udma->regs + UDMA_CH_ADDR(ch_id));
+ writel(rx_size, udma->regs + UDMA_CH_CTRL(ch_id));
+ }
+
+ /* enable interrupt */
+ reg = readl(udma->regs + r_ie) | BIT(ch_bit);
+ writel(reg, udma->regs + r_ie);
+
+ /* start DMA */
+ reg = readl(udma->regs + r_en) | BIT(ch_bit);
+ writel(reg, udma->regs + r_en);
+
+ spin_unlock_irqrestore(&udma->lock, flags);
+}
+
+static enum dma_status ast2600_udma_tx_status(struct dma_chan *chan,
+ dma_cookie_t cookie, struct dma_tx_state *txstate)
+{
+ struct ast2600_udma_chan *uc = to_ast2600_udma_chan(chan);
+ enum dma_status sts = dma_cookie_status(chan, cookie, txstate);
+
+ dma_set_residue(txstate, uc->residue);
+
+ return sts;
+}
+
+static int ast2600_udma_pause(struct dma_chan *chan)
+{
+ unsigned long flags;
+ uint32_t r_en, r_ie, reg;
+ uint32_t ch_id = chan->chan_id;
+ uint32_t ch_bit = ch_id / 2;
+ struct ast2600_udma_chan *uc = to_ast2600_udma_chan(chan);
+ struct ast2600_udma *udma = uc->udma;
+
+ if (uc->is_tx) {
+ r_en = UDMA_TX_EN;
+ r_ie = UDMA_TX_INT_EN;
+ } else {
+ r_en = UDMA_RX_EN;
+ r_ie = UDMA_RX_INT_EN;
+ }
+
+ spin_lock_irqsave(&udma->lock, flags);
+
+ reg = readl(udma->regs + r_en) & ~BIT(ch_bit);
+ writel(reg, udma->regs + r_en);
+
+ reg = readl(udma->regs + r_ie) & ~BIT(ch_bit);
+ writel(reg, udma->regs + r_ie);
+
+ spin_unlock_irqrestore(&udma->lock, flags);
+
+ return 0;
+}
+
+static int ast2600_udma_resume(struct dma_chan *chan)
+{
+ unsigned long flags;
+ uint32_t r_en, r_ie, reg;
+ uint32_t ch_id = chan->chan_id;
+ uint32_t ch_bit = ch_id / 2;
+ struct ast2600_udma_chan *uc = to_ast2600_udma_chan(chan);
+ struct ast2600_udma *udma = uc->udma;
+
+ if (uc->is_tx) {
+ r_en = UDMA_TX_EN;
+ r_ie = UDMA_TX_INT_EN;
+ } else {
+ r_en = UDMA_RX_EN;
+ r_ie = UDMA_RX_INT_EN;
+ }
+
+ spin_lock_irqsave(&udma->lock, flags);
+
+ reg = readl(udma->regs + r_en) | BIT(ch_bit);
+ writel(reg, udma->regs + r_en);
+
+ reg = readl(udma->regs + r_ie) | BIT(ch_bit);
+ writel(reg, udma->regs + r_ie);
+
+ spin_unlock_irqrestore(&udma->lock, flags);
+
+ return 0;
+}
+
+static int ast2600_udma_terminate(struct dma_chan *chan)
+{
+ unsigned long flags;
+ uint32_t r_pr, r_is, r_ie, r_en, reg;
+ uint32_t ch_id = chan->chan_id;
+ uint32_t ch_bit = ch_id / 2;
+ struct ast2600_udma_chan *uc = to_ast2600_udma_chan(chan);
+ struct ast2600_udma *udma = uc->udma;
+
+ if (uc->is_tx) {
+ r_pr = UDMA_TX_PTR_RST;
+ r_is = UDMA_TX_INT_STS;
+ r_ie = UDMA_TX_INT_EN;
+ r_en = UDMA_TX_EN;
+ } else {
+ r_pr = UDMA_RX_PTR_RST;
+ r_is = UDMA_RX_INT_STS;
+ r_ie = UDMA_RX_INT_EN;
+ r_en = UDMA_RX_EN;
+ }
+
+ spin_lock_irqsave(&udma->lock, flags);
+
+ /* disable DMA */
+ reg = readl(udma->regs + r_en) & ~BIT(ch_bit);
+ writel(reg, udma->regs + r_en);
+
+ /* disable interrupt */
+ reg = readl(udma->regs + r_ie) & ~BIT(ch_bit);
+ writel(reg, udma->regs + r_ie);
+
+ /* clear interrupt status */
+ writel(BIT(ch_bit), udma->regs + r_is);
+
+ /* reset channel HW read/write pointer */
+ writel(BIT(ch_bit), udma->regs + r_pr);
+ writel(0, udma->regs + r_pr);
+
+ spin_unlock_irqrestore(&udma->lock, flags);
+
+ return 0;
+}
+
+static irqreturn_t ast2600_udma_isr(int irq, void *arg)
+{
+ struct ast2600_udma *udma = arg;
+ struct ast2600_udma_chan *uc;
+ struct ast2600_udma_desc *ud;
+ struct dma_async_tx_descriptor *tx;
+ uint32_t sts, rptr, wptr;
+ uint32_t ch_id, ch_bit;
+ phys_addr_t pa;
+ void *va;
+
+ /* handle TX interrupt */
+ sts = readl(udma->regs + UDMA_TX_INT_STS);
+ for_each_set_bit(ch_bit, (unsigned long *)&sts, (udma->n_ucs / 2)) {
+ ch_id = ch_bit << 1;
+ rptr = readl(udma->regs + UDMA_CH_RPTR(ch_id));
+ wptr = readl(udma->regs + UDMA_CH_WPTR(ch_id));
+
+ uc = &udma->ucs[ch_id];
+ uc->residue = wptr - rptr;
+
+ ast2600_udma_terminate(&uc->chan);
+
+ tx = &uc->ud.tx;
+ dma_cookie_complete(tx);
+ dma_descriptor_unmap(tx);
+ dmaengine_desc_get_callback_invoke(tx, NULL);
+ }
+
+ /* handle RX interrupt */
+ sts = readl(udma->regs + UDMA_RX_INT_STS);
+ for_each_set_bit(ch_bit, (unsigned long *)&sts, udma->n_ucs / 2) {
+ ch_id = (ch_bit << 1) + 1;
+ wptr = readl(udma->regs + UDMA_CH_WPTR(ch_id));
+
+ uc = &udma->ucs[ch_id];
+ ud = &uc->ud;
+ tx = &ud->tx;
+
+ uc->residue = (ud->size & ~UDMA_CH_CTRL_BUFSZ) - wptr;
+
+ /* handle non-4B-aligned case */
+ if (ud->addr & 0x3) {
+ pa = dma_to_phys(uc->chan.device->dev, ud->addr);
+ if (pa != (phys_addr_t)-1) {
+ va = phys_to_virt(pa);
+ memcpy(va, uc->buf, wptr);
+ }
+ }
+
+ ast2600_udma_terminate(&uc->chan);
+
+ dma_cookie_complete(tx);
+ dma_descriptor_unmap(tx);
+ dmaengine_desc_get_callback_invoke(tx, NULL);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int ast2600_udma_probe(struct platform_device *pdev)
+{
+ int i, rc;
+ struct resource *res;
+ struct ast2600_udma *udma;
+ struct device *dev = &pdev->dev;
+
+ udma = devm_kzalloc(dev, sizeof(*udma), GFP_KERNEL);
+ if (!udma)
+ return -ENOMEM;
+
+ dma_cap_set(DMA_SLAVE, udma->ddev.cap_mask);
+ udma->ddev.device_alloc_chan_resources = ast2600_udma_alloc_chan_resources;
+ udma->ddev.device_prep_slave_sg = ast2600_udma_prep_slave_sg;
+ udma->ddev.device_issue_pending = ast2600_udma_issue_pending;
+ udma->ddev.device_tx_status = ast2600_udma_tx_status;
+ udma->ddev.device_pause = ast2600_udma_pause;
+ udma->ddev.device_resume = ast2600_udma_resume;
+ udma->ddev.device_terminate_all = ast2600_udma_terminate;
+ udma->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
+ udma->ddev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
+ udma->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+ udma->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+ udma->ddev.dev = dev;
+ INIT_LIST_HEAD(&udma->ddev.channels);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (IS_ERR(res)) {
+ dev_err(dev, "cannot get IO resource\n");
+ return -ENODEV;
+ }
+
+ udma->regs = devm_ioremap_resource(dev, res);
+ if (IS_ERR(udma->regs)) {
+ dev_err(dev, "cannot map IO registers\n");
+ return PTR_ERR(udma->regs);
+ }
+
+ /* timeout value: 0x200 * (PCLK * 14400) */
+ writel(0x200, udma->regs + UDMA_TMOUT);
+
+ /* disable all for safety */
+ writel(0x0, udma->regs + UDMA_TX_EN);
+ writel(0x0, udma->regs + UDMA_RX_EN);
+
+ udma->irq = platform_get_irq(pdev, 0);
+ if (udma->irq < 0)
+ return udma->irq;
+
+ rc = devm_request_irq(&pdev->dev, udma->irq, ast2600_udma_isr,
+ IRQF_SHARED, DEVICE_NAME, udma);
+ if (rc) {
+ dev_err(dev, "cannot request IRQ\n");
+ return rc;
+ }
+
+ rc = of_property_read_u32(dev->of_node, "dma-channels", &udma->n_ucs);
+ if (rc) {
+ dev_err(dev, "cannot find number of channels\n");
+ return rc;
+ }
+
+ udma->ucs = devm_kzalloc(dev,
+ sizeof(struct ast2600_udma_chan) * udma->n_ucs, GFP_KERNEL);
+ if (!udma->ucs)
+ return -ENOMEM;
+
+ for (i = 0; i < udma->n_ucs; ++i) {
+ udma->ucs[i].is_tx = !(i % 2);
+ udma->ucs[i].chan.device = &udma->ddev;
+ udma->ucs[i].buf = dmam_alloc_coherent(dev, UDMA_MAX_BUFSZ,
+ &udma->ucs[i].buf_addr, GFP_KERNEL);
+ if (!udma->ucs[i].buf)
+ return -ENOMEM;
+
+ udma->ucs[i].udma = udma;
+ list_add_tail(&udma->ucs[i].chan.device_node, &udma->ddev.channels);
+ }
+
+ rc = dma_async_device_register(&udma->ddev);
+ if (rc)
+ return rc;
+
+ rc = of_dma_controller_register(dev->of_node, of_dma_xlate_by_chan_id, &udma->ddev);
+ if (rc)
+ return rc;
+
+ spin_lock_init(&udma->lock);
+
+ platform_set_drvdata(pdev, udma);
+
+ dev_info(dev, "module loaded\n");
+
+ return 0;
+}
+
+static int ast2600_udma_remove(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct ast2600_udma *udma = platform_get_drvdata(pdev);
+
+ of_dma_controller_free(dev->of_node);
+ dma_async_device_unregister(&udma->ddev);
+
+ dev_info(dev, "module removed\n");
+
+ return 0;
+}
+
+static const struct of_device_id ast2600_udma_match[] = {
+ { .compatible = "aspeed,ast2600-udma" },
+ { },
+};
+
+static struct platform_driver ast2600_udma_driver = {
+ .probe = ast2600_udma_probe,
+ .remove = ast2600_udma_remove,
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = ast2600_udma_match,
+ },
+};
+
+module_platform_driver(ast2600_udma_driver);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Chia-Wei Wang <chiawei_wang at aspeedtech.com");
--
2.25.1
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