libata: add support for ATA_16 on ATAPI

(many months and hours of wasted effort later, still resending..)

This patch adds support for issuing ATA_16 passthru commands to ATAPI devices managed by libata. It requires the previous CDB length fix patch.

A boot/module parameter, "ata16_passthru=1" can be used to globally disable this feature, if ever desired.

diff -u --recursive --new-file --exclude-from=old/Documentation/dontdiff old/drivers/ata/libata-core.c new/drivers/ata/libata-core.c
@@ -82,6 +82,10 @@

module_param(atapi_dmadir, int, 0444);
MODULE_PARM_DESC(atapi_dmadir, "Enable ATAPI DMADIR bridge support (0=off, 1=on)");

+int ata16_passthru = 0;
+module_param(ata16_passthru, int, 0444);
+MODULE_PARM_DESC(ata16_passthru, "Enable passthru of SCSI opcode 0x85 to ATAPI devices (0=off, 1=on)"); +
int libata_fua = 0;
module_param_named(fua, libata_fua, int, 0444);
MODULE_PARM_DESC(fua, "FUA support (0=off, 1=on)");

diff -u --recursive --new-file --exclude-from=old/Documentation/dontdiff old/drivers/ata/libata-scsi.c new/drivers/ata/libata-scsi.c
@@ -2688,6 +2688,10 @@
 

static inline ata_xlat_func_t ata_get_xlat_func(struct ata_device *dev, u8 cmd) {
+ if (dev->class == ATA_DEV_ATAPI)
+ if (cmd != ATA_16 || ata16_passthru)
+ return atapi_xlat;
+

	switch (cmd) {
	case READ_6:
	case READ_10:

@@ -2746,27 +2750,28 @@
void (*done)(struct scsi_cmnd *), struct ata_device *dev)
{
- int rc = 0;
-
- if (unlikely(!scmd->cmd_len || scmd->cmd_len > dev->cdb_len)) {
- DPRINTK("bad CDB len=%u, max=%u\n",
- scmd->cmd_len, dev->cdb_len);
+ ata_xlat_func_t xlat_func;
+ int rc = 0, max_len;
+ u8 scsi_op = scmd->cmnd[0];
+
+ if (scsi_op == ATA_16 && dev->class == ATA_DEV_ATAPI && !ata16_passthru)
+ max_len = 16;
+ else
+ max_len = dev->cdb_len;
+ + if (unlikely(!scmd->cmd_len || scmd->cmd_len > max_len)) {
+ DPRINTK("bad CDB len=%u, max=%u\n",

+ 			scmd->cmd_len, max_len);
		scmd->result = DID_ERROR << 16;
		done(scmd);
		return 0;
	}

- if (dev->class == ATA_DEV_ATA) {
- ata_xlat_func_t xlat_func = ata_get_xlat_func(dev,
- scmd->cmnd[0]);
-
- if (xlat_func)
- rc = ata_scsi_translate(dev, scmd, done, xlat_func);
- else
- ata_scsi_simulate(dev, scmd, done);
- } else
- rc = ata_scsi_translate(dev, scmd, done, atapi_xlat);
-
+ xlat_func = ata_get_xlat_func(dev, scsi_op);
+ if (xlat_func)
+ rc = ata_scsi_translate(dev, scmd, done, xlat_func);
+ else

+		ata_scsi_simulate(dev, scmd, done);
	return rc;
}

diff -u --recursive --new-file --exclude-from=old/Documentation/dontdiff old/drivers/ata/libata.h new/drivers/ata/libata.h
@@ -47,6 +47,7 @@

extern struct workqueue_struct *ata_aux_wq;
extern int atapi_enabled;
extern int atapi_dmadir;
+extern int ata16_passthru;
extern int libata_fua;
extern struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev); extern int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev,

It applies with some warnings.

Adds trailing whitespace.
.dotest/patch:47:
Space in indent is followed by a tab.
.dotest/patch:49: DPRINTK("bad CDB len=%u, max=%u\n",
Space in indent is followed by a tab.
.dotest/patch:50: scmd->cmd_len, max_len);

Other than that.

tejun

Here it is again, without the two extraneous spaces.

This patch adds support for issuing ATA_16 passthru commands to ATAPI devices managed by libata. It requires the previous CDB length fix patch.

A boot/module parameter, "ata16_passthru=1" can be used to globally disable this feature, if ever desired.

---

diff -u --recursive --new-file --exclude-from=old/Documentation/dontdiff old/drivers/ata/libata-core.c new/drivers/ata/libata-core.c
@@ -82,6 +82,10 @@

module_param(atapi_dmadir, int, 0444);
MODULE_PARM_DESC(atapi_dmadir, "Enable ATAPI DMADIR bridge support (0=off, 1=on)");

+int ata16_passthru = 0;
+module_param(ata16_passthru, int, 0444);
+MODULE_PARM_DESC(ata16_passthru, "Enable passthru of SCSI opcode 0x85 to ATAPI devices (0=off, 1=on)"); +
int libata_fua = 0;
module_param_named(fua, libata_fua, int, 0444);
MODULE_PARM_DESC(fua, "FUA support (0=off, 1=on)");

diff -u --recursive --new-file --exclude-from=old/Documentation/dontdiff old/drivers/ata/libata-scsi.c new/drivers/ata/libata-scsi.c
@@ -2688,6 +2688,10 @@
 

static inline ata_xlat_func_t ata_get_xlat_func(struct ata_device *dev, u8 cmd) {
+ if (dev->class == ATA_DEV_ATAPI)
+ if (cmd != ATA_16 || ata16_passthru)
+ return atapi_xlat;
+

	switch (cmd) {
	case READ_6:
	case READ_10:

@@ -2746,27 +2750,28 @@
void (*done)(struct scsi_cmnd *), struct ata_device *dev)
{
- int rc = 0;
-
- if (unlikely(!scmd->cmd_len || scmd->cmd_len > dev->cdb_len)) {
- DPRINTK("bad CDB len=%u, max=%u\n",
- scmd->cmd_len, dev->cdb_len);
+ ata_xlat_func_t xlat_func;
+ int rc = 0, max_len;
+ u8 scsi_op = scmd->cmnd[0];
+
+ if (scsi_op == ATA_16 && dev->class == ATA_DEV_ATAPI && !ata16_passthru)
+ max_len = 16;
+ else
+ max_len = dev->cdb_len;
+ + if (unlikely(!scmd->cmd_len || scmd->cmd_len > max_len)) {
+ DPRINTK("bad CDB len=%u, max=%u\n",

+			scmd->cmd_len, max_len);
		scmd->result = DID_ERROR << 16;
		done(scmd);
		return 0;
	}

- if (dev->class == ATA_DEV_ATA) {
- ata_xlat_func_t xlat_func = ata_get_xlat_func(dev,
- scmd->cmnd[0]);
-
- if (xlat_func)
- rc = ata_scsi_translate(dev, scmd, done, xlat_func);
- else
- ata_scsi_simulate(dev, scmd, done);
- } else
- rc = ata_scsi_translate(dev, scmd, done, atapi_xlat);
-
+ xlat_func = ata_get_xlat_func(dev, scsi_op);
+ if (xlat_func)
+ rc = ata_scsi_translate(dev, scmd, done, xlat_func);
+ else

+		ata_scsi_simulate(dev, scmd, done);
	return rc;
}

diff -u --recursive --new-file --exclude-from=old/Documentation/dontdiff old/drivers/ata/libata.h new/drivers/ata/libata.h
@@ -47,6 +47,7 @@

extern struct workqueue_struct *ata_aux_wq;
extern int atapi_enabled;
extern int atapi_dmadir;
+extern int ata16_passthru;
extern int libata_fua;
extern struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev); extern int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev,