git: dfb736022285 - main - dwmmc: Calculate the maximum transaction length correctly.

[Michal Meloun]

The branch main has been updated by mmel:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=dfb7360222856e7e4f5e0e5564281a25af63319c

commit dfb7360222856e7e4f5e0e5564281a25af63319c
Author:     Michal Meloun <m...@freebsd.org>
AuthorDate: 2021-10-07 18:42:56 +0000
Commit:     Michal Meloun <m...@freebsd.org>
CommitDate: 2021-10-08 07:21:03 +0000

    dwmmc: Calculate the maximum transaction length correctly.
    
    We should reserve two descriptors (not MMC_SECTORS) for potentially
    unaligned (so bounced) buffer fragments, one for the starting fragment
    and one for the ending fragment.
    
    Submitted by:   kjo...@gmail.com
    MFC after:      2 weeks
    Differential Revision:  https://reviews.freebsd.org/D30387
---
 sys/dev/mmc/host/dwmmc.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/sys/dev/mmc/host/dwmmc.c b/sys/dev/mmc/host/dwmmc.c
index 77c8e42a6150..2080a973564f 100644
--- a/sys/dev/mmc/host/dwmmc.c
+++ b/sys/dev/mmc/host/dwmmc.c
@@ -145,6 +145,11 @@ struct idmac_desc {
  * second half of page
  */
 #define        IDMAC_MAX_SIZE  2048
+/*
+ * Busdma may bounce buffers, so we must reserve 2 descriptors
+ * (on start and on end) for bounced fragments.
+ */
+#define DWMMC_MAX_DATA (IDMAC_MAX_SIZE * (IDMAC_DESC_SEGS - 2)) / 
MMC_SECTOR_SIZE
 
 static void dwmmc_next_operation(struct dwmmc_softc *);
 static int dwmmc_setup_bus(struct dwmmc_softc *, int);
@@ -1358,13 +1363,7 @@ dwmmc_read_ivar(device_t bus, device_t child, int which, 
uintptr_t *result)
                *(int *)result = sc->host.caps;
                break;
        case MMCBR_IVAR_MAX_DATA:
-               /*
-                * Busdma may bounce buffers, so we must reserve 2 descriptors
-                * (on start and on end) for bounced fragments.
-                *
-                */
-               *(int *)result = (IDMAC_MAX_SIZE * IDMAC_DESC_SEGS) /
-                   MMC_SECTOR_SIZE - 3;
+               *(int *)result = DWMMC_MAX_DATA;
                break;
        case MMCBR_IVAR_TIMING:
                *(int *)result = sc->host.ios.timing;
@@ -1444,7 +1443,7 @@ dwmmc_get_tran_settings(device_t dev, struct 
ccb_trans_settings_mmc *cts)
        cts->host_f_min = sc->host.f_min;
        cts->host_f_max = sc->host.f_max;
        cts->host_caps = sc->host.caps;
-       cts->host_max_data = (IDMAC_MAX_SIZE * IDMAC_DESC_SEGS) / 
MMC_SECTOR_SIZE;
+       cts->host_max_data = DWMMC_MAX_DATA;
        memcpy(&cts->ios, &sc->host.ios, sizeof(struct mmc_ios));
 
        return (0);