[PATCH v3 14/18] ata: libata-scsi: add support for CDL pages mode sense

Niklas Cassel
2023-01-24T19:05:04Z

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

Modify ata_scsiop_mode_sense() and ata_msense_control() to support mode
sense access to the T2A and T2B sub-pages of the control mode page.
ata_msense_control() is modified to support sub-pages. The T2A sub-page
is generated using the read descriptors of the command duration limits
log page 18h. The T2B sub-page is generated using the write descriptors
of the same log page. With the addition of these sub-pages, getting all
sub-pages of the control mode page is also supported by increasing the
value of ATA_SCSI_RBUF_SIZE from 576B up to 2048B to ensure that all
sub-pages fit in the fill buffer.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Co-developed-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
drivers/ata/libata-scsi.c | 150 ++++++++++++++++++++++++++++++++------
1 file changed, 128 insertions(+), 22 deletions(-)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 2a0a04c9e658..9315a4c01276 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -37,7 +37,7 @@
#include "libata.h"
#include "libata-transport.h"

-#define ATA_SCSI_RBUF_SIZE 576
+#define ATA_SCSI_RBUF_SIZE 2048

static DEFINE_SPINLOCK(ata_scsi_rbuf_lock);
static u8 ata_scsi_rbuf[ATA_SCSI_RBUF_SIZE];
@@ -55,6 +55,9 @@ static struct ata_device *__ata_scsi_find_dev(struct ata_port *ap,
#define CONTROL_MPAGE_LEN 12
#define ALL_MPAGES 0x3f
#define ALL_SUB_MPAGES 0xff
+#define CDL_T2A_SUB_MPAGE 0x07
+#define CDL_T2B_SUB_MPAGE 0x08
+#define CDL_T2_SUB_MPAGE_LEN 232

static const u8 def_rw_recovery_mpage[RW_RECOVERY_MPAGE_LEN] = {
RW_RECOVERY_MPAGE,
@@ -2196,10 +2199,98 @@ static unsigned int ata_msense_caching(u16 *id, u8 *buf, bool changeable)
return sizeof(def_cache_mpage);
}

+/*
+ * Simulate MODE SENSE control mode page, sub-page 0.
+ */
+static unsigned int ata_msense_control_spg0(struct ata_device *dev, u8 *buf,
+ bool changeable)
+{
+ modecpy(buf, def_control_mpage,
+ sizeof(def_control_mpage), changeable);
+ if (changeable) {
+ /* ata_mselect_control() */
+ buf[2] |= (1 << 2);
+ } else {
+ bool d_sense = (dev->flags & ATA_DFLAG_D_SENSE);
+
+ /* descriptor format sense data */
+ buf[2] |= (d_sense << 2);
+ }
+
+ return sizeof(def_control_mpage);
+}
+
+/*
+ * Translate an ATA duration limit in microseconds to a SCSI duration limit
+ * using the t2cdlunits 0xa (10ms). Since the SCSI duration limits are 2-bytes
+ * only, take care of overflows.
+ */
+static inline u16 ata_xlat_cdl_limit(u8 *buf)
+{
+ u32 limit = get_unaligned_le32(buf);
+
+ return min_t(u32, limit / 10000, 65535);
+}
+
+/*
+ * Simulate MODE SENSE control mode page, sub-pages 07h and 08h
+ * (command duration limits T2A and T2B mode pages).
+ */
+static unsigned int ata_msense_control_spgt2(struct ata_device *dev, u8 *buf,
+ u8 spg)
+{
+ u8 *b, *cdl = dev->cdl, *desc;
+ u32 policy;
+ int i;
+
+ /*
+ * Fill the subpage. The first four bytes of the T2A/T2B mode pages
+ * are a header. The PAGE LENGTH field is the size of the page
+ * excluding the header.
+ */
+ buf[0] = CONTROL_MPAGE;
+ buf[1] = spg;
+ put_unaligned_be16(CDL_T2_SUB_MPAGE_LEN - 4, &buf[2]);
+ if (spg == CDL_T2A_SUB_MPAGE) {
+ /*
+ * Read descriptors map to the T2A page:
+ * set perf_vs_duration_guidleine.
+ */
+ buf[7] = (cdl[0] & 0x03) << 4;
+ desc = cdl + 64;
+ } else {
+ /* Write descriptors map to the T2B page */
+ desc = cdl + 288;
+ }
+
+ /* Fill the T2 page descriptors */
+ b = &buf[8];
+ policy = get_unaligned_le32(&cdl[0]);
+ for (i = 0; i < 7; i++, b += 32, desc += 32) {
+ /* t2cdlunits: fixed to 10ms */
+ b[0] = 0x0a;
+
+ /* Max inactive time and its policy */
+ put_unaligned_be16(ata_xlat_cdl_limit(&desc[8]), &b[2]);
+ b[6] = ((policy >> 8) & 0x0f) << 4;
+
+ /* Max active time and its policy */
+ put_unaligned_be16(ata_xlat_cdl_limit(&desc[4]), &b[4]);
+ b[6] |= (policy >> 4) & 0x0f;
+
+ /* Command duration guideline and its policy */
+ put_unaligned_be16(ata_xlat_cdl_limit(&desc[16]), &b[10]);
+ b[14] = policy & 0x0f;
+ }
+
+ return CDL_T2_SUB_MPAGE_LEN;
+}
+
/**
* ata_msense_control - Simulate MODE SENSE control mode page
* @dev: ATA device of interest
* @buf: output buffer
+ * @spg: sub-page code
* @changeable: whether changeable parameters are requested
*
* Generate a generic MODE SENSE control mode page.
@@ -2208,17 +2299,24 @@ static unsigned int ata_msense_caching(u16 *id, u8 *buf, bool changeable)
* None.
*/
static unsigned int ata_msense_control(struct ata_device *dev, u8 *buf,
- bool changeable)
+ u8 spg, bool changeable)
{
- modecpy(buf, def_control_mpage, sizeof(def_control_mpage), changeable);
- if (changeable) {
- buf[2] |= (1 << 2); /* ata_mselect_control() */
- } else {
- bool d_sense = (dev->flags & ATA_DFLAG_D_SENSE);
-
- buf[2] |= (d_sense << 2); /* descriptor format sense data */
+ unsigned int n;
+
+ switch (spg) {
+ case 0:
+ return ata_msense_control_spg0(dev, buf, changeable);
+ case CDL_T2A_SUB_MPAGE:
+ case CDL_T2B_SUB_MPAGE:
+ return ata_msense_control_spgt2(dev, buf, spg);
+ case ALL_SUB_MPAGES:
+ n = ata_msense_control_spg0(dev, buf, changeable);
+ n += ata_msense_control_spgt2(dev, buf + n, CDL_T2A_SUB_MPAGE);
+ n += ata_msense_control_spgt2(dev, buf + n, CDL_T2A_SUB_MPAGE);
+ return n;
+ default:
+ return 0;
}
- return sizeof(def_control_mpage);
}

/**
@@ -2291,13 +2389,24 @@ static unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf)

pg = scsicmd[2] & 0x3f;
spg = scsicmd[3];
+
/*
- * No mode subpages supported (yet) but asking for _all_
- * subpages may be valid
+ * Supported subpages: all subpages and sub-pages 07h and 08h of
+ * the control page.
*/
- if (spg && (spg != ALL_SUB_MPAGES)) {
- fp = 3;
- goto invalid_fld;
+ if (spg) {
+ switch (spg) {
+ case ALL_SUB_MPAGES:
+ break;
+ case CDL_T2A_SUB_MPAGE:
+ case CDL_T2B_SUB_MPAGE:
+ if (dev->flags & ATA_DFLAG_CDL && pg == CONTROL_MPAGE)
+ break;
+ fallthrough;
+ default:
+ fp = 3;
+ goto invalid_fld;
+ }
}

switch(pg) {
@@ -2310,13 +2419,13 @@ static unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf)
break;

case CONTROL_MPAGE:
- p += ata_msense_control(args->dev, p, page_control == 1);
+ p += ata_msense_control(args->dev, p, spg, page_control == 1);
break;

case ALL_MPAGES:
p += ata_msense_rw_recovery(p, page_control == 1);
p += ata_msense_caching(args->id, p, page_control == 1);
- p += ata_msense_control(args->dev, p, page_control == 1);
+ p += ata_msense_control(args->dev, p, spg, page_control == 1);
break;

default: /* invalid page code */
@@ -2335,10 +2444,7 @@ static unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf)
memcpy(rbuf + 4, sat_blk_desc, sizeof(sat_blk_desc));
}
} else {
- unsigned int output_len = p - rbuf - 2;
-
- rbuf[0] = output_len >> 8;
- rbuf[1] = output_len;
+ put_unaligned_be16(p - rbuf - 2, &rbuf[0]);
rbuf[3] |= dpofua;
if (ebd) {
rbuf[7] = sizeof(sat_blk_desc);
@@ -3637,7 +3743,7 @@ static int ata_mselect_control(struct ata_queued_cmd *qc,
/*
* Check that read-only bits are not modified.
*/
- ata_msense_control(dev, mpage, false);
+ ata_msense_control_spg0(dev, mpage, false);
for (i = 0; i < CONTROL_MPAGE_LEN - 2; i++) {
if (i == 0)
continue;
--
2.39.1