[PATCH v1 3/3] mmc: Add driver for LiteX's LiteSDCard interface

Gabriel Somlo
2021-12-03T23:42:14Z

LiteX (https://github.com/enjoy-digital/litex) is a SoC framework
that targets FPGAs. LiteSDCard is a small footprint, configurable
SDCard core commonly used in LiteX designs.

The driver was first written in May 2020 and has been maintained
cooperatively by the LiteX community. Thanks to all contributors!

Co-developed-by: Kamil Rakoczy <krakoczy@antmicro.com>
Signed-off-by: Kamil Rakoczy <krakoczy@antmicro.com>
Co-developed-by: Maciej Dudek <mdudek@internships.antmicro.com>
Signed-off-by: Maciej Dudek <mdudek@internships.antmicro.com>
Co-developed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Gabriel Somlo <gsomlo@gmail.com>
Cc: Mateusz Holenko <mholenko@antmicro.com>
Cc: Karol Gugala <kgugala@antmicro.com>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: David Abdurachmanov <david.abdurachmanov@sifive.com>
Cc: Florent Kermarrec <florent@enjoy-digital.fr>
---
drivers/mmc/host/Kconfig | 6 +
drivers/mmc/host/Makefile | 1 +
drivers/mmc/host/litex_mmc.c | 677 +++++++++++++++++++++++++++++++++++
3 files changed, 684 insertions(+)
create mode 100644 drivers/mmc/host/litex_mmc.c

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 5af8494c31b5..84c64e72195d 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -1093,3 +1093,9 @@ config MMC_OWL

config MMC_SDHCI_EXTERNAL_DMA
bool
+
+config MMC_LITEX
+ tristate "Support for the MMC Controller in LiteX SOCs"
+ depends on OF && LITEX
+ help
+ Generic MCC driver for LiteX
diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
index ea36d379bd3c..4e4ceb32c4b4 100644
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -101,6 +101,7 @@ obj-$(CONFIG_MMC_CQHCI) += cqhci.o
cqhci-y += cqhci-core.o
cqhci-$(CONFIG_MMC_CRYPTO) += cqhci-crypto.o
obj-$(CONFIG_MMC_HSQ) += mmc_hsq.o
+obj-$(CONFIG_MMC_LITEX) += litex_mmc.o

ifeq ($(CONFIG_CB710_DEBUG),y)
CFLAGS-cb710-mmc += -DDEBUG
diff --git a/drivers/mmc/host/litex_mmc.c b/drivers/mmc/host/litex_mmc.c
new file mode 100644
index 000000000000..3877379757cd
--- /dev/null
+++ b/drivers/mmc/host/litex_mmc.c
@@ -0,0 +1,677 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * LiteX LiteSDCard driver
+ *
+ * Copyright (C) 2019-2020 Antmicro <www.antmicro.com>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/litex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/mmc/sd.h>
+#include <linux/mmc/mmc.h>
+#include <linux/mmc/host.h>
+#include <linux/mmc/slot-gpio.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+
+#define LITEX_PHY_CARDDETECT 0x00
+#define LITEX_PHY_CLOCKERDIV 0x04
+#define LITEX_PHY_INITIALIZE 0x08
+#define LITEX_PHY_WRITESTATUS 0x0C
+#define LITEX_CORE_CMDARG 0x00
+#define LITEX_CORE_CMDCMD 0x04
+#define LITEX_CORE_CMDSND 0x08
+#define LITEX_CORE_CMDRSP 0x0C
+#define LITEX_CORE_CMDEVT 0x1C
+#define LITEX_CORE_DATAEVT 0x20
+#define LITEX_CORE_BLKLEN 0x24
+#define LITEX_CORE_BLKCNT 0x28
+#define LITEX_BLK2MEM_BASE 0x00
+#define LITEX_BLK2MEM_LEN 0x08
+#define LITEX_BLK2MEM_ENA 0x0C
+#define LITEX_BLK2MEM_DONE 0x10
+#define LITEX_BLK2MEM_LOOP 0x14
+#define LITEX_MEM2BLK_BASE 0x00
+#define LITEX_MEM2BLK_LEN 0x08
+#define LITEX_MEM2BLK_ENA 0x0C
+#define LITEX_MEM2BLK_DONE 0x10
+#define LITEX_MEM2BLK_LOOP 0x14
+#define LITEX_MEM2BLK 0x18
+#define LITEX_IRQ_STATUS 0x00
+#define LITEX_IRQ_PENDING 0x04
+#define LITEX_IRQ_ENABLE 0x08
+
+#define SDCARD_CTRL_DATA_TRANSFER_NONE 0
+#define SDCARD_CTRL_DATA_TRANSFER_READ 1
+#define SDCARD_CTRL_DATA_TRANSFER_WRITE 2
+
+#define SDCARD_CTRL_RESPONSE_NONE 0
+#define SDCARD_CTRL_RESPONSE_SHORT 1
+#define SDCARD_CTRL_RESPONSE_LONG 2
+#define SDCARD_CTRL_RESPONSE_SHORT_BUSY 3
+
+#define SD_OK 0
+#define SD_WRITEERROR 1
+#define SD_TIMEOUT 2
+#define SD_CRCERROR 3
+#define SD_ERR_OTHER 4
+
+#define SDIRQ_CARD_DETECT 1
+#define SDIRQ_SD_TO_MEM_DONE 2
+#define SDIRQ_MEM_TO_SD_DONE 4
+#define SDIRQ_CMD_DONE 8
+
+struct litex_mmc_host {
+ struct mmc_host *mmc;
+ struct platform_device *dev;
+
+ void __iomem *sdphy;
+ void __iomem *sdcore;
+ void __iomem *sdreader;
+ void __iomem *sdwriter;
+ void __iomem *sdirq;
+
+ u32 resp[4];
+ u16 rca;
+
+ void *buffer;
+ size_t buf_size;
+ dma_addr_t dma;
+
+ unsigned int freq;
+ unsigned int clock;
+ bool is_bus_width_set;
+ bool app_cmd;
+
+ int irq;
+ struct completion cmd_done;
+};
+
+static int
+sdcard_wait_done(void __iomem *reg)
+{
+ u8 evt;
+
+ for (;;) {
+ evt = litex_read8(reg);
+ if (evt & 0x1)
+ break;
+ udelay(5);
+ }
+ if (evt == 0x1)
+ return SD_OK;
+ if (evt & 0x2)
+ return SD_WRITEERROR;
+ if (evt & 0x4)
+ return SD_TIMEOUT;
+ if (evt & 0x8)
+ return SD_CRCERROR;
+ pr_err("%s: unknown error evt=%x\n", __func__, evt);
+ return SD_ERR_OTHER;
+}
+
+static int
+send_cmd(struct litex_mmc_host *host,
+ u8 cmd, u32 arg, u8 response_len, u8 transfer)
+{
+ void __iomem *reg;
+ ulong n;
+ u8 i;
+ int status;
+
+ litex_write32(host->sdcore + LITEX_CORE_CMDARG, arg);
+ litex_write32(host->sdcore + LITEX_CORE_CMDCMD,
+ cmd << 8 | transfer << 5 | response_len);
+ litex_write8(host->sdcore + LITEX_CORE_CMDSND, 1);
+
+ /* Wait for an interrupt if we have an interrupt and either there is
+ * data to be transferred, or if the card can report busy via DAT0.
+ */
+ if (host->irq > 0 &&
+ (transfer != SDCARD_CTRL_DATA_TRANSFER_NONE ||
+ response_len == SDCARD_CTRL_RESPONSE_SHORT_BUSY)) {
+ reinit_completion(&host->cmd_done);
+ litex_write32(host->sdirq + LITEX_IRQ_ENABLE,
+ SDIRQ_CMD_DONE | SDIRQ_CARD_DETECT);
+ wait_for_completion(&host->cmd_done);
+ }
+
+ status = sdcard_wait_done(host->sdcore + LITEX_CORE_CMDEVT);
+
+ if (status != SD_OK) {
+ pr_err("Command (cmd %d) failed, status %d\n", cmd, status);
+ return status;
+ }
+
+ if (response_len != SDCARD_CTRL_RESPONSE_NONE) {
+ reg = host->sdcore + LITEX_CORE_CMDRSP;
+ for (i = 0; i < 4; i++) {
+ host->resp[i] = litex_read32(reg);
+ reg += sizeof(u32);
+ }
+ }
+
+ if (!host->app_cmd && cmd == SD_SEND_RELATIVE_ADDR)
+ host->rca = (host->resp[3] >> 16) & 0xffff;
+
+ host->app_cmd = (cmd == MMC_APP_CMD);
+
+ if (transfer == SDCARD_CTRL_DATA_TRANSFER_NONE)
+ return status; /* SD_OK from prior sdcard_wait_done(cmd_evt) */
+
+ status = sdcard_wait_done(host->sdcore + LITEX_CORE_DATAEVT);
+ if (status != SD_OK) {
+ pr_err("Data xfer (cmd %d) failed, status %d\n", cmd, status);
+ return status;
+ }
+
+ /* wait for completion of (read or write) DMA transfer */
+ reg = (transfer == SDCARD_CTRL_DATA_TRANSFER_READ) ?
+ host->sdreader + LITEX_BLK2MEM_DONE :
+ host->sdwriter + LITEX_MEM2BLK_DONE;
+ n = jiffies + (HZ << 1);
+ while ((litex_read8(reg) & 0x01) == 0)
+ if (time_after(jiffies, n)) {
+ pr_err("DMA timeout (cmd %d)\n", cmd);
+ return SD_TIMEOUT;
+ }
+
+ return status;
+}
+
+static inline int
+send_app_cmd(struct litex_mmc_host *host)
+{
+ return send_cmd(host, MMC_APP_CMD, host->rca << 16,
+ SDCARD_CTRL_RESPONSE_SHORT,
+ SDCARD_CTRL_DATA_TRANSFER_NONE);
+}
+
+static inline int
+send_app_set_bus_width_cmd(struct litex_mmc_host *host, u32 width)
+{
+ return send_cmd(host, SD_APP_SET_BUS_WIDTH, width,
+ SDCARD_CTRL_RESPONSE_SHORT,
+ SDCARD_CTRL_DATA_TRANSFER_NONE);
+}
+
+static int
+litex_set_bus_width(struct litex_mmc_host *host)
+{
+ bool app_cmd_sent = host->app_cmd; /* was preceding command app_cmd? */
+ int status;
+
+ /* ensure 'app_cmd' precedes 'app_set_bus_width_cmd' */
+ if (!app_cmd_sent)
+ send_app_cmd(host);
+
+ /* litesdcard only supports 4-bit bus width */
+ status = send_app_set_bus_width_cmd(host, MMC_BUS_WIDTH_4);
+
+ /* re-send 'app_cmd' if necessary */
+ if (app_cmd_sent)
+ send_app_cmd(host);
+
+ return status;
+}
+
+static int
+litex_get_cd(struct mmc_host *mmc)
+{
+ struct litex_mmc_host *host = mmc_priv(mmc);
+ int ret;
+
+ if (!mmc_card_is_removable(mmc))
+ return 1;
+
+ ret = mmc_gpio_get_cd(mmc);
+ if (ret >= 0)
+ /* GPIO based card-detect explicitly specified in DTS */
+ ret = !!ret;
+ else
+ /* use gateware card-detect bit by default */
+ ret = !litex_read8(host->sdphy + LITEX_PHY_CARDDETECT);
+
+ /* ensure bus width will be set (again) upon card (re)insertion */
+ if (ret == 0)
+ host->is_bus_width_set = false;
+
+ return ret;
+}
+
+static irqreturn_t
+litex_mmc_interrupt(int irq, void *arg)
+{
+ struct mmc_host *mmc = arg;
+ struct litex_mmc_host *host = mmc_priv(mmc);
+ u32 pending = litex_read32(host->sdirq + LITEX_IRQ_PENDING);
+
+ /* Check for card change interrupt */
+ if (pending & SDIRQ_CARD_DETECT) {
+ litex_write32(host->sdirq + LITEX_IRQ_PENDING,
+ SDIRQ_CARD_DETECT);
+ mmc_detect_change(mmc, msecs_to_jiffies(10));
+ }
+
+ /* Check for command completed */
+ if (pending & SDIRQ_CMD_DONE) {
+ /* Disable it so it doesn't keep interrupting */
+ litex_write32(host->sdirq + LITEX_IRQ_ENABLE,
+ SDIRQ_CARD_DETECT);
+ complete(&host->cmd_done);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static u32
+litex_response_len(struct mmc_command *cmd)
+{
+ if (cmd->flags & MMC_RSP_136) {
+ return SDCARD_CTRL_RESPONSE_LONG;
+ } else if (cmd->flags & MMC_RSP_PRESENT) {
+ if (cmd->flags & MMC_RSP_BUSY)
+ return SDCARD_CTRL_RESPONSE_SHORT_BUSY;
+ else
+ return SDCARD_CTRL_RESPONSE_SHORT;
+ }
+ return SDCARD_CTRL_RESPONSE_NONE;
+}
+
+static int
+litex_map_status(int status)
+{
+ int error;
+
+ switch (status) {
+ case SD_OK:
+ error = 0;
+ break;
+ case SD_WRITEERROR:
+ error = -EIO;
+ break;
+ case SD_TIMEOUT:
+ error = -ETIMEDOUT;
+ break;
+ case SD_CRCERROR:
+ error = -EILSEQ;
+ break;
+ default:
+ error = -EINVAL;
+ break;
+ }
+ return error;
+}
+
+static void
+litex_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+ struct litex_mmc_host *host = mmc_priv(mmc);
+ struct platform_device *pdev = to_platform_device(mmc->parent);
+ struct device *dev = &pdev->dev;
+ struct mmc_data *data = mrq->data;
+ struct mmc_command *sbc = mrq->sbc;
+ struct mmc_command *cmd = mrq->cmd;
+ struct mmc_command *stop = mrq->stop;
+ unsigned int retries = cmd->retries;
+ int status;
+ int sg_count;
+ enum dma_data_direction dir = DMA_TO_DEVICE;
+ bool direct = false;
+ dma_addr_t dma;
+ unsigned int len = 0;
+
+ u32 response_len = litex_response_len(cmd);
+ u32 transfer = SDCARD_CTRL_DATA_TRANSFER_NONE;
+
+ /* First check that the card is still there */
+ if (!litex_get_cd(mmc)) {
+ cmd->error = -ENOMEDIUM;
+ mmc_request_done(mmc, mrq);
+ return;
+ }
+
+ /* Send set-block-count command if needed */
+ if (sbc) {
+ status = send_cmd(host, sbc->opcode, sbc->arg,
+ litex_response_len(sbc),
+ SDCARD_CTRL_DATA_TRANSFER_NONE);
+ sbc->error = litex_map_status(status);
+ if (status != SD_OK) {
+ host->is_bus_width_set = false;
+ mmc_request_done(mmc, mrq);
+ return;
+ }
+ }
+
+ if (data) {
+ /* LiteSDCard only supports 4-bit bus width; therefore, we MUST
+ * inject a SET_BUS_WIDTH (acmd6) before the very first data
+ * transfer, earlier than when the mmc subsystem would normally
+ * get around to it!
+ */
+ if (!host->is_bus_width_set) {
+ ulong n = jiffies + 2 * HZ; // 500ms timeout
+
+ while (litex_set_bus_width(host) != SD_OK) {
+ if (time_after(jiffies, n)) {
+ dev_warn(dev, "Can't set bus width!\n");
+ cmd->error = -ETIMEDOUT;
+ mmc_request_done(mmc, mrq);
+ return;
+ }
+ }
+ host->is_bus_width_set = true;
+ }
+
+ /* Try to DMA directly to/from the data buffer.
+ * We can do that if the buffer can be mapped for DMA
+ * in one contiguous chunk.
+ */
+ dma = host->dma;
+ len = data->blksz * data->blocks;
+ if (data->flags & MMC_DATA_READ)
+ dir = DMA_FROM_DEVICE;
+ sg_count = dma_map_sg(&host->dev->dev,
+ data->sg, data->sg_len, dir);
+ if (sg_count == 1) {
+ dma = sg_dma_address(data->sg);
+ len = sg_dma_len(data->sg);
+ direct = true;
+ } else if (len > host->buf_size)
+ len = host->buf_size;
+
+ if (data->flags & MMC_DATA_READ) {
+ litex_write8(host->sdreader + LITEX_BLK2MEM_ENA, 0);
+ litex_write64(host->sdreader + LITEX_BLK2MEM_BASE, dma);
+ litex_write32(host->sdreader + LITEX_BLK2MEM_LEN, len);
+ litex_write8(host->sdreader + LITEX_BLK2MEM_ENA, 1);
+
+ transfer = SDCARD_CTRL_DATA_TRANSFER_READ;
+ } else if (data->flags & MMC_DATA_WRITE) {
+ if (!direct)
+ sg_copy_to_buffer(data->sg, data->sg_len,
+ host->buffer, len);
+
+ litex_write8(host->sdwriter + LITEX_MEM2BLK_ENA, 0);
+ litex_write64(host->sdwriter + LITEX_MEM2BLK_BASE, dma);
+ litex_write32(host->sdwriter + LITEX_MEM2BLK_LEN, len);
+ litex_write8(host->sdwriter + LITEX_MEM2BLK_ENA, 1);
+
+ transfer = SDCARD_CTRL_DATA_TRANSFER_WRITE;
+ } else {
+ dev_warn(dev, "Data present w/o read or write flag.\n");
+ /* Continue: set cmd status, mark req done */
+ }
+
+ litex_write16(host->sdcore + LITEX_CORE_BLKLEN, data->blksz);
+ litex_write32(host->sdcore + LITEX_CORE_BLKCNT, data->blocks);
+ }
+
+ do {
+ status = send_cmd(host, cmd->opcode, cmd->arg,
+ response_len, transfer);
+ } while (status != SD_OK && retries-- > 0);
+
+ cmd->error = litex_map_status(status);
+ if (status != SD_OK)
+ /* card may be gone; don't assume bus width is still set */
+ host->is_bus_width_set = false;
+
+ if (response_len == SDCARD_CTRL_RESPONSE_SHORT) {
+ /* pull short response fields from appropriate host registers */
+ cmd->resp[0] = host->resp[3];
+ cmd->resp[1] = host->resp[2] & 0xFF;
+ } else if (response_len == SDCARD_CTRL_RESPONSE_LONG) {
+ cmd->resp[0] = host->resp[0];
+ cmd->resp[1] = host->resp[1];
+ cmd->resp[2] = host->resp[2];
+ cmd->resp[3] = host->resp[3];
+ }
+
+ /* Send stop-transmission command if required */
+ if (stop && (cmd->error || !sbc)) {
+ int stop_stat;
+
+ stop_stat = send_cmd(host, stop->opcode, stop->arg,
+ litex_response_len(stop),
+ SDCARD_CTRL_DATA_TRANSFER_NONE);
+ stop->error = litex_map_status(stop_stat);
+ if (stop_stat != SD_OK)
+ host->is_bus_width_set = false;
+ }
+
+ if (data)
+ dma_unmap_sg(&host->dev->dev, data->sg, data->sg_len, dir);
+
+ if (status == SD_OK && transfer != SDCARD_CTRL_DATA_TRANSFER_NONE) {
+ data->bytes_xfered = min(len, mmc->max_req_size);
+ if (transfer == SDCARD_CTRL_DATA_TRANSFER_READ && !direct) {
+ sg_copy_from_buffer(data->sg, sg_nents(data->sg),
+ host->buffer, data->bytes_xfered);
+ }
+ }
+
+ mmc_request_done(mmc, mrq);
+}
+
+static void
+litex_set_clk(struct litex_mmc_host *host, unsigned int clk_freq)
+{
+ u32 div = clk_freq ? host->freq / clk_freq : 256;
+
+ div = roundup_pow_of_two(div);
+ div = min_t(u32, max_t(u32, div, 2), 256);
+ dev_info(&host->dev->dev, "clk_freq=%d: set to %d via div=%d\n",
+ clk_freq, host->freq / div, div);
+ litex_write16(host->sdphy + LITEX_PHY_CLOCKERDIV, div);
+}
+
+static void
+litex_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+ struct litex_mmc_host *host = mmc_priv(mmc);
+
+ /* NOTE: Ignore any ios->bus_width updates; they occur right after
+ * the mmc core sends its own acmd6 bus-width change notification,
+ * which is redundant since we snoop on the command flow and inject
+ * an early acmd6 before the first data transfer command is sent!
+ */
+
+ /* update sdcard clock */
+ if (ios->clock != host->clock) {
+ litex_set_clk(host, ios->clock);
+ host->clock = ios->clock;
+ }
+}
+
+static const struct mmc_host_ops litex_mmc_ops = {
+ .get_cd = litex_get_cd,
+ .request = litex_request,
+ .set_ios = litex_set_ios,
+};
+
+static int
+litex_mmc_probe(struct platform_device *pdev)
+{
+ struct litex_mmc_host *host;
+ struct mmc_host *mmc;
+ struct device_node *cpu;
+ int ret;
+
+ mmc = mmc_alloc_host(sizeof(struct litex_mmc_host), &pdev->dev);
+ /* NOTE: defaults to max_[req,seg]_size=PAGE_SIZE, max_blk_size=512,
+ * and max_blk_count accordingly set to 8;
+ * If for some reason we need to modify max_blk_count, we must also
+ * re-calculate `max_[req,seg]_size = max_blk_size * max_blk_count;`
+ */
+ if (!mmc)
+ return -ENOMEM;
+
+ host = mmc_priv(mmc);
+ host->mmc = mmc;
+ host->dev = pdev;
+
+ host->clock = 0;
+ cpu = of_get_next_cpu_node(NULL);
+ ret = of_property_read_u32(cpu, "clock-frequency", &host->freq);
+ of_node_put(cpu);
+ if (ret) {
+ dev_err(&pdev->dev, "No \"clock-frequency\" property in DT\n");
+ goto err_free_host;
+ }
+
+ init_completion(&host->cmd_done);
+ host->irq = platform_get_irq(pdev, 0);
+ if (host->irq < 0)
+ dev_err(&pdev->dev, "Failed to get IRQ, using polling\n");
+
+ /* LiteSDCard only supports 4-bit bus width; therefore, we MUST inject
+ * a SET_BUS_WIDTH (acmd6) before the very first data transfer, earlier
+ * than when the mmc subsystem would normally get around to it!
+ */
+ host->is_bus_width_set = false;
+ host->app_cmd = false;
+
+ ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
+ if (ret)
+ goto err_free_host;
+
+ host->buf_size = mmc->max_req_size * 2;
+ host->buffer = dma_alloc_coherent(&pdev->dev, host->buf_size,
+ &host->dma, GFP_DMA);
+ if (host->buffer == NULL) {
+ ret = -ENOMEM;
+ goto err_free_host;
+ }
+
+ host->sdphy = devm_platform_ioremap_resource_byname(pdev, "phy");
+ if (IS_ERR(host->sdphy)) {
+ ret = PTR_ERR(host->sdphy);
+ goto err_free_dma;
+ }
+
+ host->sdcore = devm_platform_ioremap_resource_byname(pdev, "core");
+ if (IS_ERR(host->sdcore)) {
+ ret = PTR_ERR(host->sdcore);
+ goto err_free_dma;
+ }
+
+ host->sdreader = devm_platform_ioremap_resource_byname(pdev, "reader");
+ if (IS_ERR(host->sdreader)) {
+ ret = PTR_ERR(host->sdreader);
+ goto err_free_dma;
+ }
+
+ host->sdwriter = devm_platform_ioremap_resource_byname(pdev, "writer");
+ if (IS_ERR(host->sdwriter)) {
+ ret = PTR_ERR(host->sdwriter);
+ goto err_free_dma;
+ }
+
+ if (host->irq > 0) {
+ host->sdirq = devm_platform_ioremap_resource_byname(pdev, "irq");
+ if (IS_ERR(host->sdirq)) {
+ ret = PTR_ERR(host->sdirq);
+ goto err_free_dma;
+ }
+ }
+
+ mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
+ mmc->ops = &litex_mmc_ops;
+
+ mmc->f_min = 12.5e6;
+ mmc->f_max = 50e6;
+
+ ret = mmc_of_parse(mmc);
+ if (ret)
+ goto err_free_dma;
+
+ /* force 4-bit bus_width (only width supported by hardware) */
+ mmc->caps &= ~MMC_CAP_8_BIT_DATA;
+ mmc->caps |= MMC_CAP_4_BIT_DATA;
+
+ /* set default capabilities */
+ mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY |
+ MMC_CAP_DRIVER_TYPE_D |
+ MMC_CAP_CMD23;
+ mmc->caps2 |= MMC_CAP2_NO_WRITE_PROTECT |
+ MMC_CAP2_FULL_PWR_CYCLE |
+ MMC_CAP2_NO_SDIO;
+
+ platform_set_drvdata(pdev, host);
+
+ ret = mmc_add_host(mmc);
+ if (ret < 0)
+ goto err_free_dma;
+
+ /* ensure DMA bus masters are disabled */
+ litex_write8(host->sdreader + LITEX_BLK2MEM_ENA, 0);
+ litex_write8(host->sdwriter + LITEX_MEM2BLK_ENA, 0);
+
+ /* set up interrupt handler */
+ if (host->irq > 0) {
+ ret = request_irq(host->irq, litex_mmc_interrupt, 0,
+ "litex-mmc", mmc);
+ if (ret < 0) {
+ dev_err(&pdev->dev,
+ "irq setup error %d, using polling\n", ret);
+ host->irq = 0;
+ }
+ }
+
+ /* enable card-change interrupts, or else ask for polling */
+ if (host->irq > 0) {
+ litex_write32(host->sdirq + LITEX_IRQ_PENDING,
+ SDIRQ_CARD_DETECT); /* clears it */
+ litex_write32(host->sdirq + LITEX_IRQ_ENABLE,
+ SDIRQ_CARD_DETECT);
+ } else {
+ mmc->caps |= MMC_CAP_NEEDS_POLL;
+ }
+
+ return 0;
+
+err_free_dma:
+ dma_free_coherent(&pdev->dev, host->buf_size, host->buffer, host->dma);
+err_free_host:
+ mmc_free_host(mmc);
+ return ret;
+}
+
+static int
+litex_mmc_remove(struct platform_device *pdev)
+{
+ struct litex_mmc_host *host = dev_get_drvdata(&pdev->dev);
+
+ if (host->irq > 0)
+ free_irq(host->irq, host->mmc);
+ mmc_remove_host(host->mmc);
+ dma_free_coherent(&pdev->dev, host->buf_size, host->buffer, host->dma);
+ mmc_free_host(host->mmc);
+
+ return 0;
+}
+
+static const struct of_device_id litex_match[] = {
+ { .compatible = "litex,mmc" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, litex_match);
+
+static struct platform_driver litex_mmc_driver = {
+ .probe = litex_mmc_probe,
+ .remove = litex_mmc_remove,
+ .driver = {
+ .name = "litex-mmc",
+ .of_match_table = of_match_ptr(litex_match),
+ },
+};
+module_platform_driver(litex_mmc_driver);
+
+MODULE_DESCRIPTION("LiteX SDCard driver");
+MODULE_AUTHOR("Antmicro <www.antmicro.com>");
+MODULE_LICENSE("GPL v2");
--
2.31.1