storage_erase.c

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * MultiMediaCard (MMC), eMMC and Secure Digital (SD) erase support code.
 * This code is controller independent.
 */
 
#include "sd_mmc.h"
#include "storage.h"
 
uint64_t storage_block_erase(struct storage_media *media, uint64_t start,
        uint64_t count)
{
        struct mmc_command cmd;
        struct sd_mmc_ctrlr *ctrlr = media->ctrlr;
 
        if (storage_block_setup(media, start, count, 0) == 0)
                return 0;
 
        cmd.cmdidx = MMC_CMD_ERASE_GROUP_START;
        cmd.resp_type = CARD_RSP_R1;
        cmd.cmdarg = start;
        cmd.flags = 0;
 
        if (ctrlr->send_cmd(ctrlr, &cmd, NULL))
                return 0;
 
        cmd.cmdidx = MMC_CMD_ERASE_GROUP_END;
        cmd.cmdarg = start + count - 1;
        cmd.resp_type = CARD_RSP_R1;
        cmd.flags = 0;
 
        if (ctrlr->send_cmd(ctrlr, &cmd, NULL))
                return 0;
 
        cmd.cmdidx = MMC_CMD_ERASE;
        cmd.cmdarg = MMC_TRIM_ARG;      /* just unmap blocks */
        cmd.resp_type = CARD_RSP_R1;
        cmd.flags = 0;
 
        if (ctrlr->send_cmd(ctrlr, &cmd, NULL))
                return 0;
 
        size_t erase_blocks;
        /*
         * Timeout for TRIM operation on one erase group is defined as:
         * TRIM timeout = 300ms x TRIM_MULT
         *
         * This timeout is expressed in units of 100us to sd_mmc_send_status.
         *
         * Hence, timeout_per_erase_block = TRIM timeout * 1000us/100us;
         */
        size_t timeout_per_erase_block = (media->trim_mult * 300) * 10;
        int err = 0;
 
        erase_blocks = ALIGN_UP(count, media->erase_blocks)
                / media->erase_blocks;
 
        while (erase_blocks) {
                /*
                 * To avoid overflow of timeout value, loop in calls to
                 * sd_mmc_send_status for erase_blocks number of times.
                 */
                err = sd_mmc_send_status(media, timeout_per_erase_block);
 
                /* Send status successful, erase action complete. */
                if (err == 0)
                        break;
 
                erase_blocks--;
        }
 
        /* Total timeout done. Still status not successful. */
        if (err) {
                sd_mmc_error("TRIM operation not successful within timeout.\n");
                return 0;
        }
 
        return count;
}