dm: mmc: sandbox: Add an SD-card emulation

Add an emulation of an SD card to sandbox, allowing MMC to be used in tests.
The emulation is very simple, supporting only card detection and reading
test data.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/mmc/Kconfig

@@ -2,7 +2,7 @@ menu "MMC Host controller Support"
 
 config MMC
 	bool "Enable MMC support"
-	depends on ARCH_SUNXI
+	depends on ARCH_SUNXI || SANDBOX
 	help
 	  TODO: Move all architectures to use this option
 
@@ -58,4 +58,13 @@ config MMC_UNIPHIER
 	help
 	  This selects support for the SD/MMC Host Controller on UniPhier SoCs.
 
+config SANDBOX_MMC
+	bool "Sandbox MMC support"
+	depends on MMC && SANDBOX
+	help
+	  This select a dummy sandbox MMC driver. At present this does nothing
+	  other than allow sandbox to be build with MMC support. This
+	  improves build coverage for sandbox and makes it easier to detect
+	  MMC build errors with sandbox.
+
 endmenu

drivers/mmc/sandbox_mmc.c

@@ -8,18 +8,150 @@
 #include <common.h>
 #include <dm.h>
 #include <errno.h>
+#include <fdtdec.h>
 #include <mmc.h>
 #include <asm/test.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
+struct sandbox_mmc_plat {
+	struct mmc_config cfg;
+	struct mmc mmc;
+};
+
+/**
+ * sandbox_mmc_send_cmd() - Emulate SD commands
+ *
+ * This emulate an SD card version 2. Single-block reads result in zero data.
+ * Multiple-block reads return a test string.
+ */
+static int sandbox_mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
+				struct mmc_data *data)
+{
+	switch (cmd->cmdidx) {
+	case MMC_CMD_ALL_SEND_CID:
+		break;
+	case SD_CMD_SEND_RELATIVE_ADDR:
+		cmd->response[0] = 0 << 16; /* mmc->rca */
+	case MMC_CMD_GO_IDLE_STATE:
+		break;
+	case SD_CMD_SEND_IF_COND:
+		cmd->response[0] = 0xaa;
+		break;
+	case MMC_CMD_SEND_STATUS:
+		cmd->response[0] = MMC_STATUS_RDY_FOR_DATA;
+		break;
+	case MMC_CMD_SELECT_CARD:
+		break;
+	case MMC_CMD_SEND_CSD:
+		cmd->response[0] = 0;
+		cmd->response[1] = 10 << 16;	/* 1 << block_len */
+		break;
+	case SD_CMD_SWITCH_FUNC: {
+		u32 *resp = (u32 *)data->dest;
+
+		resp[7] = cpu_to_be32(SD_HIGHSPEED_BUSY);
+		break;
+	}
+	case MMC_CMD_READ_SINGLE_BLOCK:
+		memset(data->dest, '\0', data->blocksize);
+		break;
+	case MMC_CMD_READ_MULTIPLE_BLOCK:
+		strcpy(data->dest, "this is a test");
+		break;
+	case MMC_CMD_STOP_TRANSMISSION:
+		break;
+	case SD_CMD_APP_SEND_OP_COND:
+		cmd->response[0] = OCR_BUSY | OCR_HCS;
+		cmd->response[1] = 0;
+		cmd->response[2] = 0;
+		break;
+	case MMC_CMD_APP_CMD:
+		break;
+	case MMC_CMD_SET_BLOCKLEN:
+		debug("block len %d\n", cmd->cmdarg);
+		break;
+	case SD_CMD_APP_SEND_SCR: {
+		u32 *scr = (u32 *)data->dest;
+
+		scr[0] = cpu_to_be32(2 << 24 | 1 << 15);  /* SD version 3 */
+		break;
+	}
+	default:
+		debug("%s: Unknown command %d\n", __func__, cmd->cmdidx);
+		break;
+	}
+
+	return 0;
+}
+
+static void sandbox_mmc_set_ios(struct mmc *mmc)
+{
+}
+
+static int sandbox_mmc_init(struct mmc *mmc)
+{
+	return 0;
+}
+
+static int sandbox_mmc_getcd(struct mmc *mmc)
+{
+	return 1;
+}
+
+static const struct mmc_ops sandbox_mmc_ops = {
+	.send_cmd = sandbox_mmc_send_cmd,
+	.set_ios = sandbox_mmc_set_ios,
+	.init = sandbox_mmc_init,
+	.getcd = sandbox_mmc_getcd,
+};
+
+int sandbox_mmc_probe(struct udevice *dev)
+{
+	struct sandbox_mmc_plat *plat = dev_get_platdata(dev);
+
+	return mmc_init(&plat->mmc);
+}
+
+int sandbox_mmc_bind(struct udevice *dev)
+{
+	struct sandbox_mmc_plat *plat = dev_get_platdata(dev);
+	struct mmc_config *cfg = &plat->cfg;
+	int ret;
+
+	cfg->name = dev->name;
+	cfg->ops = &sandbox_mmc_ops;
+	cfg->host_caps = MMC_MODE_HS_52MHz | MMC_MODE_HS | MMC_MODE_8BIT;
+	cfg->voltages = MMC_VDD_165_195 | MMC_VDD_32_33 | MMC_VDD_33_34;
+	cfg->f_min = 1000000;
+	cfg->f_max = 52000000;
+	cfg->b_max = U32_MAX;
+
+	ret = mmc_bind(dev, &plat->mmc, cfg);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+int sandbox_mmc_unbind(struct udevice *dev)
+{
+	mmc_unbind(dev);
+
+	return 0;
+}
+
 static const struct udevice_id sandbox_mmc_ids[] = {
 	{ .compatible = "sandbox,mmc" },
 	{ }
 };
 
-U_BOOT_DRIVER(warm_mmc_sandbox) = {
+U_BOOT_DRIVER(mmc_sandbox) = {
 	.name		= "mmc_sandbox",
 	.id		= UCLASS_MMC,
 	.of_match	= sandbox_mmc_ids,
+	.bind		= sandbox_mmc_bind,
+	.unbind		= sandbox_mmc_unbind,
+	.probe		= sandbox_mmc_probe,
+	.platdata_auto_alloc_size = sizeof(struct sandbox_mmc_plat),
 };