mmc: renesas-sdhi: add support for R-Car Gen3 SDHI DMAC

Add a new variant of the SDHI driver to support R-Car Gen3 with DMA via
on-chip bus mastering.  Since the DMAC is in a part of the SDHI module it
is not suitable to be used via DMA Engine.

Clearing of DM_CM_INFO1 after DMA thanks to Dirk Behme

Cc: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Ai Kyuse <ai.kyuse.uw@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 271 insertions, 0 deletions

diff --git a/drivers/mmc/host/renesas_sdhi_internal_dmac.c b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
new file mode 100644
index 000000000000..a26c6ed8e029
--- /dev/null
+++ b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
@@ -0,0 +1,271 @@
+/*
+ * DMA support for Internal DMAC with SDHI SD/SDIO controller
+ *
+ * Copyright (C) 2016-17 Renesas Electronics Corporation
+ * Copyright (C) 2016-17 Horms Solutions, Simon Horman
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/io-64-nonatomic-hi-lo.h>
+#include <linux/mfd/tmio.h>
+#include <linux/mmc/host.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/pagemap.h>
+#include <linux/scatterlist.h>
+
+#include "renesas_sdhi.h"
+#include "tmio_mmc.h"
+
+#define DM_CM_DTRAN_MODE	0x820
+#define DM_CM_DTRAN_CTRL	0x828
+#define DM_CM_RST		0x830
+#define DM_CM_INFO1		0x840
+#define DM_CM_INFO1_MASK	0x848
+#define DM_CM_INFO2		0x850
+#define DM_CM_INFO2_MASK	0x858
+#define DM_DTRAN_ADDR		0x880
+
+/* DM_CM_DTRAN_MODE */
+#define DTRAN_MODE_CH_NUM_CH0	0	/* "downstream" = for write commands */
+#define DTRAN_MODE_CH_NUM_CH1	BIT(16)	/* "uptream" = for read commands */
+#define DTRAN_MODE_BUS_WID_TH	(BIT(5) | BIT(4))
+#define DTRAN_MODE_ADDR_MODE	BIT(0)	/* 1 = Increment address */
+
+/* DM_CM_DTRAN_CTRL */
+#define DTRAN_CTRL_DM_START	BIT(0)
+
+/* DM_CM_RST */
+#define RST_DTRANRST1		BIT(9)
+#define RST_DTRANRST0		BIT(8)
+#define RST_RESERVED_BITS	GENMASK_ULL(32, 0)
+
+/* DM_CM_INFO1 and DM_CM_INFO1_MASK */
+#define INFO1_CLEAR		0
+#define INFO1_DTRANEND1		BIT(17)
+#define INFO1_DTRANEND0		BIT(16)
+
+/* DM_CM_INFO2 and DM_CM_INFO2_MASK */
+#define INFO2_DTRANERR1		BIT(17)
+#define INFO2_DTRANERR0		BIT(16)
+
+/*
+ * Specification of this driver:
+ * - host->chan_{rx,tx} will be used as a flag of enabling/disabling the dma
+ * - Since this SDHI DMAC register set has 16 but 32-bit width, we
+ *   need a custom accessor.
+ */
+
+/* Definitions for sampling clocks */
+static struct renesas_sdhi_scc rcar_gen3_scc_taps[] = {
+	{
+		.clk_rate = 0,
+		.tap = 0x00000300,
+	},
+};
+
+static const struct renesas_sdhi_of_data of_rcar_gen3_compatible = {
+	.tmio_flags	= TMIO_MMC_HAS_IDLE_WAIT | TMIO_MMC_WRPROTECT_DISABLE |
+			  TMIO_MMC_CLK_ACTUAL | TMIO_MMC_MIN_RCAR2,
+	.capabilities	= MMC_CAP_SD_HIGHSPEED | MMC_CAP_SDIO_IRQ |
+			  MMC_CAP_CMD23,
+	.bus_shift	= 2,
+	.scc_offset	= 0x1000,
+	.taps		= rcar_gen3_scc_taps,
+	.taps_num	= ARRAY_SIZE(rcar_gen3_scc_taps),
+	/* Gen3 SDHI DMAC can handle 0xffffffff blk count, but seg = 1 */
+	.max_blk_count	= 0xffffffff,
+	.max_segs	= 1,
+};
+
+static const struct of_device_id renesas_sdhi_internal_dmac_of_match[] = {
+	{ .compatible = "renesas,sdhi-r8a7795", .data = &of_rcar_gen3_compatible, },
+	{ .compatible = "renesas,sdhi-r8a7796", .data = &of_rcar_gen3_compatible, },
+	{},
+};
+MODULE_DEVICE_TABLE(of, renesas_sdhi_internal_dmac_of_match);
+
+static void
+renesas_sdhi_internal_dmac_dm_write(struct tmio_mmc_host *host,
+				    int addr, u64 val)
+{
+	writeq(val, host->ctl + addr);
+}
+
+static void
+renesas_sdhi_internal_dmac_enable_dma(struct tmio_mmc_host *host, bool enable)
+{
+	if (!host->chan_tx || !host->chan_rx)
+		return;
+
+	if (!enable)
+		renesas_sdhi_internal_dmac_dm_write(host, DM_CM_INFO1,
+						    INFO1_CLEAR);
+
+	if (host->dma->enable)
+		host->dma->enable(host, enable);
+}
+
+static void
+renesas_sdhi_internal_dmac_abort_dma(struct tmio_mmc_host *host) {
+	u64 val = RST_DTRANRST1 | RST_DTRANRST0;
+
+	renesas_sdhi_internal_dmac_enable_dma(host, false);
+
+	renesas_sdhi_internal_dmac_dm_write(host, DM_CM_RST,
+					    RST_RESERVED_BITS & ~val);
+	renesas_sdhi_internal_dmac_dm_write(host, DM_CM_RST,
+					    RST_RESERVED_BITS | val);
+
+	renesas_sdhi_internal_dmac_enable_dma(host, true);
+}
+
+static void
+renesas_sdhi_internal_dmac_dataend_dma(struct tmio_mmc_host *host) {
+	tasklet_schedule(&host->dma_complete);
+}
+
+static void
+renesas_sdhi_internal_dmac_start_dma(struct tmio_mmc_host *host,
+				     struct mmc_data *data)
+{
+	struct scatterlist *sg = host->sg_ptr;
+	u32 dtran_mode = DTRAN_MODE_BUS_WID_TH | DTRAN_MODE_ADDR_MODE;
+	enum dma_data_direction dir;
+	int ret;
+	u32 irq_mask;
+
+	/* This DMAC cannot handle if sg_len is not 1 */
+	WARN_ON(host->sg_len > 1);
+
+	/* This DMAC cannot handle if buffer is not 8-bytes alignment */
+	if (!IS_ALIGNED(sg->offset, 8)) {
+		host->force_pio = true;
+		renesas_sdhi_internal_dmac_enable_dma(host, false);
+		return;
+	}
+
+	if (data->flags & MMC_DATA_READ) {
+		dtran_mode |= DTRAN_MODE_CH_NUM_CH1;
+		dir = DMA_FROM_DEVICE;
+		irq_mask = TMIO_STAT_RXRDY;
+	} else {
+		dtran_mode |= DTRAN_MODE_CH_NUM_CH0;
+		dir = DMA_TO_DEVICE;
+		irq_mask = TMIO_STAT_TXRQ;
+	}
+
+	ret = dma_map_sg(&host->pdev->dev, sg, host->sg_len, dir);
+	if (ret < 0)
+		return;
+
+	renesas_sdhi_internal_dmac_enable_dma(host, true);
+
+	/* disable PIO irqs to avoid "PIO IRQ in DMA mode!" */
+	tmio_mmc_disable_mmc_irqs(host, irq_mask);
+
+	/* set dma parameters */
+	renesas_sdhi_internal_dmac_dm_write(host, DM_CM_DTRAN_MODE,
+					    dtran_mode);
+	renesas_sdhi_internal_dmac_dm_write(host, DM_DTRAN_ADDR,
+					    sg->dma_address);
+}
+
+static void renesas_sdhi_internal_dmac_issue_tasklet_fn(unsigned long arg)
+{
+	struct tmio_mmc_host *host = (struct tmio_mmc_host *)arg;
+
+	tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
+
+	/* start the DMAC */
+	renesas_sdhi_internal_dmac_dm_write(host, DM_CM_DTRAN_CTRL,
+					    DTRAN_CTRL_DM_START);
+}
+
+static void renesas_sdhi_internal_dmac_complete_tasklet_fn(unsigned long arg)
+{
+	struct tmio_mmc_host *host = (struct tmio_mmc_host *)arg;
+	enum dma_data_direction dir;
+
+	spin_lock_irq(&host->lock);
+
+	if (!host->data)
+		goto out;
+
+	if (host->data->flags & MMC_DATA_READ)
+		dir = DMA_FROM_DEVICE;
+	else
+		dir = DMA_TO_DEVICE;
+
+	renesas_sdhi_internal_dmac_enable_dma(host, false);
+	dma_unmap_sg(&host->pdev->dev, host->sg_ptr, host->sg_len, dir);
+
+	tmio_mmc_do_data_irq(host);
+out:
+	spin_unlock_irq(&host->lock);
+}
+
+static void
+renesas_sdhi_internal_dmac_request_dma(struct tmio_mmc_host *host,
+				       struct tmio_mmc_data *pdata)
+{
+	/* Each value is set to non-zero to assume "enabling" each DMA */
+	host->chan_rx = host->chan_tx = (void *)0xdeadbeaf;
+
+	tasklet_init(&host->dma_complete,
+		     renesas_sdhi_internal_dmac_complete_tasklet_fn,
+		     (unsigned long)host);
+	tasklet_init(&host->dma_issue,
+		     renesas_sdhi_internal_dmac_issue_tasklet_fn,
+		     (unsigned long)host);
+}
+
+static void
+renesas_sdhi_internal_dmac_release_dma(struct tmio_mmc_host *host)
+{
+	/* Each value is set to zero to assume "disabling" each DMA */
+	host->chan_rx = host->chan_tx = NULL;
+}
+
+static struct tmio_mmc_dma_ops renesas_sdhi_internal_dmac_dma_ops = {
+	.start = renesas_sdhi_internal_dmac_start_dma,
+	.enable = renesas_sdhi_internal_dmac_enable_dma,
+	.request = renesas_sdhi_internal_dmac_request_dma,
+	.release = renesas_sdhi_internal_dmac_release_dma,
+	.abort = renesas_sdhi_internal_dmac_abort_dma,
+	.dataend = renesas_sdhi_internal_dmac_dataend_dma,
+};
+
+static int renesas_sdhi_internal_dmac_probe(struct platform_device *pdev)
+{
+	return renesas_sdhi_probe(pdev, &renesas_sdhi_internal_dmac_dma_ops);
+}
+
+static const struct dev_pm_ops renesas_sdhi_internal_dmac_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+	SET_RUNTIME_PM_OPS(tmio_mmc_host_runtime_suspend,
+			   tmio_mmc_host_runtime_resume,
+			   NULL)
+};
+
+static struct platform_driver renesas_internal_dmac_sdhi_driver = {
+	.driver		= {
+		.name	= "renesas_sdhi_internal_dmac",
+		.pm	= &renesas_sdhi_internal_dmac_dev_pm_ops,
+		.of_match_table = renesas_sdhi_internal_dmac_of_match,
+	},
+	.probe		= renesas_sdhi_internal_dmac_probe,
+	.remove		= renesas_sdhi_remove,
+};
+
+module_platform_driver(renesas_internal_dmac_sdhi_driver);
+
+MODULE_DESCRIPTION("Renesas SDHI driver for internal DMAC");
+MODULE_AUTHOR("Yoshihiro Shimoda");
+MODULE_LICENSE("GPL v2");