-static const struct ata_port_operations nv_generic_ops = {
- .tf_load = ata_tf_load,
- .tf_read = ata_tf_read,
- .exec_command = ata_exec_command,
- .check_status = ata_check_status,
- .dev_select = ata_std_dev_select,
- .bmdma_setup = ata_bmdma_setup,
- .bmdma_start = ata_bmdma_start,
- .bmdma_stop = ata_bmdma_stop,
- .bmdma_status = ata_bmdma_status,
- .qc_prep = ata_qc_prep,
- .qc_issue = ata_qc_issue_prot,
- .freeze = ata_bmdma_freeze,
- .thaw = ata_bmdma_thaw,
- .error_handler = nv_error_handler,
- .post_internal_cmd = ata_bmdma_post_internal_cmd,
- .data_xfer = ata_data_xfer,
- .irq_clear = ata_bmdma_irq_clear,
- .irq_on = ata_irq_on,
+/*
+ * NV SATA controllers have various different problems with hardreset
+ * protocol depending on the specific controller and device.
+ *
+ * GENERIC:
+ *
+ * bko11195 reports that link doesn't come online after hardreset on
+ * generic nv's and there have been several other similar reports on
+ * linux-ide.
+ *
+ * bko12351#c23 reports that warmplug on MCP61 doesn't work with
+ * softreset.
+ *
+ * NF2/3:
+ *
+ * bko3352 reports nf2/3 controllers can't determine device signature
+ * reliably after hardreset. The following thread reports detection
+ * failure on cold boot with the standard debouncing timing.
+ *
+ * http://thread.gmane.org/gmane.linux.ide/34098
+ *
+ * bko12176 reports that hardreset fails to bring up the link during
+ * boot on nf2.
+ *
+ * CK804:
+ *
+ * For initial probing after boot and hot plugging, hardreset mostly
+ * works fine on CK804 but curiously, reprobing on the initial port
+ * by rescanning or rmmod/insmod fails to acquire the initial D2H Reg
+ * FIS in somewhat undeterministic way.
+ *
+ * SWNCQ:
+ *
+ * bko12351 reports that when SWNCQ is enabled, for hotplug to work,
+ * hardreset should be used and hardreset can't report proper
+ * signature, which suggests that mcp5x is closer to nf2 as long as
+ * reset quirkiness is concerned.
+ *
+ * bko12703 reports that boot probing fails for intel SSD with
+ * hardreset. Link fails to come online. Softreset works fine.
+ *
+ * The failures are varied but the following patterns seem true for
+ * all flavors.
+ *
+ * - Softreset during boot always works.
+ *
+ * - Hardreset during boot sometimes fails to bring up the link on
+ * certain comibnations and device signature acquisition is
+ * unreliable.
+ *
+ * - Hardreset is often necessary after hotplug.
+ *
+ * So, preferring softreset for boot probing and error handling (as
+ * hardreset might bring down the link) but using hardreset for
+ * post-boot probing should work around the above issues in most
+ * cases. Define nv_hardreset() which only kicks in for post-boot
+ * probing and use it for all variants.
+ */
+static struct ata_port_operations nv_generic_ops = {
+ .inherits = &ata_bmdma_port_ops,
+ .lost_interrupt = ATA_OP_NULL,