[Qemu-devel] [PATCH 12/20] sdcard: Let sd_frame48_crc7_calc() work on response frames

[Philippe Mathieu-Daudé]

Currently sd_calc_frame48_crc7() only works for request frames, having
the bit 6 hardwire to 1.

Extend it to handle response frames, adding a 'is_response' boolean argument.

Signed-off-by: Philippe Mathieu-Daudé <f4...@amsat.org>
---
 include/hw/sd/sd.h     |  6 ++++--
 hw/sd/sd.c             |  2 +-
 hw/sd/sdmmc-internal.c | 20 ++++++++++----------
 3 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/include/hw/sd/sd.h b/include/hw/sd/sd.h
index b65107ffe1..b1f865fe20 100644
--- a/include/hw/sd/sd.h
+++ b/include/hw/sd/sd.h
@@ -171,20 +171,22 @@ void sd_prepare_request_with_crc(SDRequest *req, uint8_t 
cmd, uint32_t arg,
 /**
  * sd_update_frame48_checksum:
  * @frame: the #SDFrame48 to verify
+ * @is_response: whether the frame is a command request or response
  *
  * Update the 7-bit CRC checksum of a SD 48-bit frame.
  */
-void sd_update_frame48_checksum(SDFrame48 *frame);
+void sd_update_frame48_checksum(SDFrame48 *frame, bool is_response);
 
 /**
  * sd_verify_frame48_checksum:
  * @frame: the #SDFrame48 to verify
+ * @is_response: whether the frame is a command request or response
  *
  * Verify the 7-bit CRC checksum of a SD 48-bit frame.
  *
  * Returns: A boolean indicating whether the frame 7-bit CRC is correct.
  */
-bool sd_verify_frame48_checksum(SDFrame48 *frame);
+bool sd_verify_frame48_checksum(SDFrame48 *frame, bool is_response);
 
 /* Legacy functions to be used only by non-qdevified callers */
 SDState *sd_init(BlockBackend *bs, bool is_spi);
diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index 2d2c31d308..5e0b5c2b87 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -452,7 +452,7 @@ static void sd_set_sdstatus(SDState *sd)
 static bool sd_req_crc_validate(SDState *sd, SDRequest *req)
 {
     if (sd->validate_crc) {
-        return sd_verify_frame48_checksum(req);
+        return sd_verify_frame48_checksum(req, false);
     }
     return true;
 }
diff --git a/hw/sd/sdmmc-internal.c b/hw/sd/sdmmc-internal.c
index 97f5f71569..04da81e665 100644
--- a/hw/sd/sdmmc-internal.c
+++ b/hw/sd/sdmmc-internal.c
@@ -109,45 +109,45 @@ uint16_t sd_crc16(const void *message, size_t width)
     return shift_reg;
 }
 
-static uint8_t sd_calc_frame48_crc7(uint8_t cmd, uint32_t arg)
+static uint8_t sd_calc_frame48_crc7(uint8_t cmd, uint32_t arg, bool 
is_response)
 {
     uint8_t buffer[5];
-    buffer[0] = 0x40 | cmd;
+    buffer[0] = (!is_response << 6) | cmd;
     stl_be_p(&buffer[1], arg);
     return sd_crc7(buffer, sizeof(buffer));
 }
 
-bool sd_verify_frame48_checksum(SDFrame48 *frame)
+bool sd_verify_frame48_checksum(SDFrame48 *frame, bool is_response)
 {
-    uint8_t crc = sd_calc_frame48_crc7(frame->cmd, frame->arg);
+    uint8_t crc = sd_calc_frame48_crc7(frame->cmd, frame->arg, is_response);
 
     return crc == frame->crc;
 }
 
-void sd_update_frame48_checksum(SDFrame48 *frame)
+void sd_update_frame48_checksum(SDFrame48 *frame, bool is_response)
 {
-    frame->crc = sd_calc_frame48_crc7(frame->cmd, frame->arg);
+    frame->crc = sd_calc_frame48_crc7(frame->cmd, frame->arg, is_response);
 }
 
 static void sd_prepare_frame48(SDFrame48 *frame, uint8_t cmd, uint32_t arg,
-                               bool gen_crc)
+                               bool is_response, bool gen_crc)
 {
     frame->cmd = cmd;
     frame->arg = arg;
     frame->crc = 0x00;
     if (gen_crc) {
-        sd_update_frame48_checksum(frame);
+        sd_update_frame48_checksum(frame, is_response);
     }
 }
 
 void sd_prepare_request(SDFrame48 *req, uint8_t cmd, uint32_t arg, bool 
gen_crc)
 {
-    sd_prepare_frame48(req, cmd, arg, gen_crc);
+    sd_prepare_frame48(req, cmd, arg, /* is_response */ false, gen_crc);
 }
 
 void sd_prepare_request_with_crc(SDRequest *req, uint8_t cmd, uint32_t arg,
                                  uint8_t crc)
 {
-    sd_prepare_frame48(req, cmd, arg, /* gen_crc */ false);
+    sd_prepare_request(req, cmd, arg, /* gen_crc */ false);
     req->crc = crc;
 }
-- 
2.17.0