{"id":2224334,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2224334/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260417-sdcard-performance-b4-v4-2-119e66be10c2@avm.de/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/1.2/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":"","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260417-sdcard-performance-b4-v4-2-119e66be10c2@avm.de>","list_archive_url":null,"date":"2026-04-17T09:51:35","name":"[v4,2/7] hw/sd/sd: Allow multi-byte read/write for generic paths","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"8de49898289a35921fbd083018aedd408df5c650","submitter":{"id":91343,"url":"http://patchwork.ozlabs.org/api/1.2/people/91343/?format=json","name":"Christian Speich","email":"c.speich@avm.de"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260417-sdcard-performance-b4-v4-2-119e66be10c2@avm.de/mbox/","series":[{"id":500297,"url":"http://patchwork.ozlabs.org/api/1.2/series/500297/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=500297","date":"2026-04-17T09:51:34","name":"hw/sd: Improve performance of read/write/erase","version":4,"mbox":"http://patchwork.ozlabs.org/series/500297/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2224334/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2224334/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=avm.de header.i=@avm.de header.a=rsa-sha256\n header.s=mail header.b=E28HWfUH;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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charset=\"utf-8\"","X-purgate-ID":"149429::1776419845-38707233-2F1C2574/0/0","X-purgate-type":"clean","X-purgate-size":"7064","X-purgate-Ad":"Categorized by eleven eXpurgate (R) https://www.eleven.de","X-purgate":["This mail is considered clean (visit https://www.eleven.de for\n further information)","clean"],"Received-SPF":"pass client-ip=212.42.244.119; envelope-from=c.speich@avm.de;\n helo=mail.avm.de","X-Spam_score_int":"-48","X-Spam_score":"-4.9","X-Spam_bar":"----","X-Spam_report":"(-4.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.54,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001,\n RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001,\n SPF_PASS=-0.001 autolearn=ham autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"Paths that use sd_generic_write/read_data can now write/read multiple\nbytes with one call.\n\nSigned-off-by: Christian Speich \nReviewed-by: Philippe Mathieu-Daudé \n---\n hw/sd/sd.c | 62 +++++++++++++++++++++++++++++++++++---------------------------\n 1 file changed, 35 insertions(+), 27 deletions(-)","diff":"diff --git a/hw/sd/sd.c b/hw/sd/sd.c\nindex 135113add29b5ee3cb11d9d535355eba8f6cb3f7..2c81776df316feda75f97e15cc9bbd1538f1a21c 100644\n--- a/hw/sd/sd.c\n+++ b/hw/sd/sd.c\n@@ -1609,7 +1609,7 @@ static sd_rsp_type_t sd_cmd_optional(SDState *sd, SDRequest req)\n return sd_illegal;\n }\n \n-/* Configure fields for following sd_generic_write_byte() calls */\n+/* Configure fields for following sd_generic_write_data() calls */\n static sd_rsp_type_t sd_cmd_to_receivingdata(SDState *sd, SDRequest req,\n uint64_t start, size_t size)\n {\n@@ -1624,7 +1624,7 @@ static sd_rsp_type_t sd_cmd_to_receivingdata(SDState *sd, SDRequest req,\n return sd_r1;\n }\n \n-/* Configure fields for following sd_generic_read_byte() calls */\n+/* Configure fields for following sd_generic_read_data() calls */\n static sd_rsp_type_t sd_cmd_to_sendingdata(SDState *sd, SDRequest req,\n uint64_t start,\n const void *data, size_t size)\n@@ -2614,11 +2614,15 @@ send_response:\n }\n \n /* Return true if buffer is consumed. Configured by sd_cmd_to_receivingdata() */\n-static bool sd_generic_write_byte(SDState *sd, uint8_t value)\n+static bool sd_generic_write_data(SDState *sd, const void *buf, size_t *len)\n {\n- sd->data[sd->data_offset] = value;\n+ size_t to_write = MIN(sd->data_size - sd->data_offset, *len);\n \n- if (++sd->data_offset >= sd->data_size) {\n+ memcpy(sd->data, buf, to_write);\n+ sd->data_offset += to_write;\n+ *len = to_write;\n+\n+ if (sd->data_offset >= sd->data_size) {\n sd->state = sd_transfer_state;\n return true;\n }\n@@ -2626,11 +2630,15 @@ static bool sd_generic_write_byte(SDState *sd, uint8_t value)\n }\n \n /* Return true when buffer is consumed. Configured by sd_cmd_to_sendingdata() */\n-static bool sd_generic_read_byte(SDState *sd, uint8_t *value)\n+static bool sd_generic_read_data(SDState *sd, void *buf, size_t *len)\n {\n- *value = sd->data[sd->data_offset];\n+ size_t to_read = MIN(sd->data_size - sd->data_offset, *len);\n+\n+ memcpy(buf, sd->data, to_read);\n+ sd->data_offset += to_read;\n+ *len = to_read;\n \n- if (++sd->data_offset >= sd->data_size) {\n+ if (sd->data_offset >= sd->data_size) {\n sd->state = sd_transfer_state;\n return true;\n }\n@@ -2657,18 +2665,12 @@ static size_t sd_write_data(SDState *sd, const void *buf, size_t length)\n if (sd->card_status & (ADDRESS_ERROR | WP_VIOLATION))\n return length;\n \n- /*\n- * Only read one byte at a time. We will be called again with the\n- * remaining.\n- */\n- length = 1;\n-\n trace_sdcard_write_data(sd->proto->name,\n sd->last_cmd_name,\n sd->current_cmd, sd->data_offset, value[0]);\n switch (sd->current_cmd) {\n case 24: /* CMD24: WRITE_SINGLE_BLOCK */\n- if (sd_generic_write_byte(sd, value[0])) {\n+ if (sd_generic_write_data(sd, buf, &length)) {\n /* TODO: Check CRC before committing */\n sd->state = sd_programming_state;\n sd_blk_write(sd, sd->data_start, sd->data_offset);\n@@ -2680,6 +2682,12 @@ static size_t sd_write_data(SDState *sd, const void *buf, size_t length)\n break;\n \n case 25: /* CMD25: WRITE_MULTIPLE_BLOCK */\n+ /*\n+ * Only read one byte at a time. We will be called again with the\n+ * remaining.\n+ */\n+ length = 1;\n+\n if (sd->data_offset == 0) {\n /* Start of the block - let's check the address is valid */\n if (!address_in_range(sd, \"WRITE_MULTIPLE_BLOCK\",\n@@ -2723,7 +2731,7 @@ static size_t sd_write_data(SDState *sd, const void *buf, size_t length)\n break;\n \n case 26: /* CMD26: PROGRAM_CID */\n- if (sd_generic_write_byte(sd, value[0])) {\n+ if (sd_generic_write_data(sd, buf, &length)) {\n /* TODO: Check CRC before committing */\n sd->state = sd_programming_state;\n for (i = 0; i < sizeof(sd->cid); i ++)\n@@ -2741,7 +2749,7 @@ static size_t sd_write_data(SDState *sd, const void *buf, size_t length)\n break;\n \n case 27: /* CMD27: PROGRAM_CSD */\n- if (sd_generic_write_byte(sd, value[0])) {\n+ if (sd_generic_write_data(sd, buf, &length)) {\n /* TODO: Check CRC before committing */\n sd->state = sd_programming_state;\n for (i = 0; i < sizeof(sd->csd); i ++)\n@@ -2764,7 +2772,7 @@ static size_t sd_write_data(SDState *sd, const void *buf, size_t length)\n break;\n \n case 42: /* CMD42: LOCK_UNLOCK */\n- if (sd_generic_write_byte(sd, value[0])) {\n+ if (sd_generic_write_data(sd, buf, &length)) {\n /* TODO: Check CRC before committing */\n sd->state = sd_programming_state;\n sd_lock_command(sd);\n@@ -2774,7 +2782,7 @@ static size_t sd_write_data(SDState *sd, const void *buf, size_t length)\n break;\n \n case 56: /* CMD56: GEN_CMD */\n- sd_generic_write_byte(sd, value[0]);\n+ sd_generic_write_data(sd, buf, &length);\n break;\n \n default:\n@@ -2809,12 +2817,6 @@ static size_t sd_read_data(SDState *sd, void *buf, size_t length)\n return length;\n }\n \n- /*\n- * We will only read one byte at a time. We will be called again with the\n- * remaining buffer.\n- */\n- length = 1;\n-\n io_len = sd_blk_len(sd);\n \n trace_sdcard_read_data(sd->proto->name,\n@@ -2832,10 +2834,16 @@ static size_t sd_read_data(SDState *sd, void *buf, size_t length)\n case 30: /* CMD30: SEND_WRITE_PROT */\n case 51: /* ACMD51: SEND_SCR */\n case 56: /* CMD56: GEN_CMD */\n- sd_generic_read_byte(sd, value);\n+ sd_generic_read_data(sd, buf, &length);\n break;\n \n case 18: /* CMD18: READ_MULTIPLE_BLOCK */\n+ /*\n+ * We will only read one byte at a time. We will be called again with\n+ * the remaining buffer.\n+ */\n+ length = 1;\n+\n if (sd->data_offset == 0) {\n if (!address_in_range(sd, \"READ_MULTIPLE_BLOCK\",\n sd->data_start, io_len)) {\n@@ -2868,7 +2876,7 @@ static size_t sd_read_data(SDState *sd, void *buf, size_t length)\n default:\n qemu_log_mask(LOG_GUEST_ERROR, \"%s: DAT read illegal for command %s\\n\",\n __func__, sd->last_cmd_name);\n- *value = dummy_byte;\n+ memset(buf, dummy_byte, length);\n }\n \n return length;\n","prefixes":["v4","2/7"]}