xref: /openbmc/qemu/hw/scsi/emulation.c (revision ffe98631)
1 #include "qemu/osdep.h"
2 #include "qemu/units.h"
3 #include "qemu/bswap.h"
4 #include "hw/scsi/emulation.h"
5 
6 int scsi_emulate_block_limits(uint8_t *outbuf, const SCSIBlockLimits *bl)
7 {
8     /* required VPD size with unmap support */
9     memset(outbuf, 0, 0x3c);
10 
11     outbuf[0] = bl->wsnz; /* wsnz */
12 
13     if (bl->max_io_sectors) {
14         /* optimal transfer length granularity.  This field and the optimal
15          * transfer length can't be greater than maximum transfer length.
16          */
17         stw_be_p(outbuf + 2, MIN(bl->min_io_size, bl->max_io_sectors));
18 
19         /* maximum transfer length */
20         stl_be_p(outbuf + 4, bl->max_io_sectors);
21 
22         /* optimal transfer length */
23         stl_be_p(outbuf + 8, MIN(bl->opt_io_size, bl->max_io_sectors));
24     } else {
25         stw_be_p(outbuf + 2, bl->min_io_size);
26         stl_be_p(outbuf + 8, bl->opt_io_size);
27     }
28 
29     /* max unmap LBA count */
30     stl_be_p(outbuf + 16, bl->max_unmap_sectors);
31 
32     /* max unmap descriptors */
33     stl_be_p(outbuf + 20, bl->max_unmap_descr);
34 
35     /* optimal unmap granularity; alignment is zero */
36     stl_be_p(outbuf + 24, bl->unmap_sectors);
37 
38     /* max write same size, make it the same as maximum transfer length */
39     stl_be_p(outbuf + 36, bl->max_io_sectors);
40 
41     return 0x3c;
42 }
43