mmc: don't support write & erase for SPL builds

For SPL builds this is just dead code since we'll only need to read.
Eliminating it results in a significant size reduction for the SPL
binary, which may be critical for certain platforms where the binary
size is highly constrained.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Acked-by: Pantelis Antoniou <panto@antoniou-consulting.com>
diff --git a/drivers/mmc/mmc_write.c b/drivers/mmc/mmc_write.c
new file mode 100644
index 0000000..aa2fdef
--- /dev/null
+++ b/drivers/mmc/mmc_write.c
@@ -0,0 +1,179 @@
+/*
+ * Copyright 2008, Freescale Semiconductor, Inc
+ * Andy Fleming
+ *
+ * Based vaguely on the Linux code
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+#include <common.h>
+#include <part.h>
+#include "mmc_private.h"
+
+static ulong mmc_erase_t(struct mmc *mmc, ulong start, lbaint_t blkcnt)
+{
+	struct mmc_cmd cmd;
+	ulong end;
+	int err, start_cmd, end_cmd;
+
+	if (mmc->high_capacity) {
+		end = start + blkcnt - 1;
+	} else {
+		end = (start + blkcnt - 1) * mmc->write_bl_len;
+		start *= mmc->write_bl_len;
+	}
+
+	if (IS_SD(mmc)) {
+		start_cmd = SD_CMD_ERASE_WR_BLK_START;
+		end_cmd = SD_CMD_ERASE_WR_BLK_END;
+	} else {
+		start_cmd = MMC_CMD_ERASE_GROUP_START;
+		end_cmd = MMC_CMD_ERASE_GROUP_END;
+	}
+
+	cmd.cmdidx = start_cmd;
+	cmd.cmdarg = start;
+	cmd.resp_type = MMC_RSP_R1;
+
+	err = mmc_send_cmd(mmc, &cmd, NULL);
+	if (err)
+		goto err_out;
+
+	cmd.cmdidx = end_cmd;
+	cmd.cmdarg = end;
+
+	err = mmc_send_cmd(mmc, &cmd, NULL);
+	if (err)
+		goto err_out;
+
+	cmd.cmdidx = MMC_CMD_ERASE;
+	cmd.cmdarg = SECURE_ERASE;
+	cmd.resp_type = MMC_RSP_R1b;
+
+	err = mmc_send_cmd(mmc, &cmd, NULL);
+	if (err)
+		goto err_out;
+
+	return 0;
+
+err_out:
+	puts("mmc erase failed\n");
+	return err;
+}
+
+unsigned long mmc_berase(int dev_num, lbaint_t start, lbaint_t blkcnt)
+{
+	int err = 0;
+	struct mmc *mmc = find_mmc_device(dev_num);
+	lbaint_t blk = 0, blk_r = 0;
+	int timeout = 1000;
+
+	if (!mmc)
+		return -1;
+
+	if ((start % mmc->erase_grp_size) || (blkcnt % mmc->erase_grp_size))
+		printf("\n\nCaution! Your devices Erase group is 0x%x\n"
+		       "The erase range would be change to "
+		       "0x" LBAF "~0x" LBAF "\n\n",
+		       mmc->erase_grp_size, start & ~(mmc->erase_grp_size - 1),
+		       ((start + blkcnt + mmc->erase_grp_size)
+		       & ~(mmc->erase_grp_size - 1)) - 1);
+
+	while (blk < blkcnt) {
+		blk_r = ((blkcnt - blk) > mmc->erase_grp_size) ?
+			mmc->erase_grp_size : (blkcnt - blk);
+		err = mmc_erase_t(mmc, start + blk, blk_r);
+		if (err)
+			break;
+
+		blk += blk_r;
+
+		/* Waiting for the ready status */
+		if (mmc_send_status(mmc, timeout))
+			return 0;
+	}
+
+	return blk;
+}
+
+static ulong mmc_write_blocks(struct mmc *mmc, lbaint_t start,
+		lbaint_t blkcnt, const void *src)
+{
+	struct mmc_cmd cmd;
+	struct mmc_data data;
+	int timeout = 1000;
+
+	if ((start + blkcnt) > mmc->block_dev.lba) {
+		printf("MMC: block number 0x" LBAF " exceeds max(0x" LBAF ")\n",
+		       start + blkcnt, mmc->block_dev.lba);
+		return 0;
+	}
+
+	if (blkcnt == 0)
+		return 0;
+	else if (blkcnt == 1)
+		cmd.cmdidx = MMC_CMD_WRITE_SINGLE_BLOCK;
+	else
+		cmd.cmdidx = MMC_CMD_WRITE_MULTIPLE_BLOCK;
+
+	if (mmc->high_capacity)
+		cmd.cmdarg = start;
+	else
+		cmd.cmdarg = start * mmc->write_bl_len;
+
+	cmd.resp_type = MMC_RSP_R1;
+
+	data.src = src;
+	data.blocks = blkcnt;
+	data.blocksize = mmc->write_bl_len;
+	data.flags = MMC_DATA_WRITE;
+
+	if (mmc_send_cmd(mmc, &cmd, &data)) {
+		printf("mmc write failed\n");
+		return 0;
+	}
+
+	/* SPI multiblock writes terminate using a special
+	 * token, not a STOP_TRANSMISSION request.
+	 */
+	if (!mmc_host_is_spi(mmc) && blkcnt > 1) {
+		cmd.cmdidx = MMC_CMD_STOP_TRANSMISSION;
+		cmd.cmdarg = 0;
+		cmd.resp_type = MMC_RSP_R1b;
+		if (mmc_send_cmd(mmc, &cmd, NULL)) {
+			printf("mmc fail to send stop cmd\n");
+			return 0;
+		}
+	}
+
+	/* Waiting for the ready status */
+	if (mmc_send_status(mmc, timeout))
+		return 0;
+
+	return blkcnt;
+}
+
+ulong mmc_bwrite(int dev_num, lbaint_t start, lbaint_t blkcnt, const void *src)
+{
+	lbaint_t cur, blocks_todo = blkcnt;
+
+	struct mmc *mmc = find_mmc_device(dev_num);
+	if (!mmc)
+		return 0;
+
+	if (mmc_set_blocklen(mmc, mmc->write_bl_len))
+		return 0;
+
+	do {
+		cur = (blocks_todo > mmc->b_max) ?  mmc->b_max : blocks_todo;
+		if (mmc_write_blocks(mmc, start, cur, src) != cur)
+			return 0;
+		blocks_todo -= cur;
+		start += cur;
+		src += cur * mmc->write_bl_len;
+	} while (blocks_todo > 0);
+
+	return blkcnt;
+}