kernel - AHCI hotplug work to help support AMD chipsets

* Change the Hot-plug mechanics to something which appears to work for
  both NVidia and AMD AHCI chipsets, and hopefully Intel too (untested).

  This appears to fix hot-plug for AMD's SB850-based AHCI (circa AM3 socket
  mobos).

* Basically the SCTL.DET and CMD.SUD bits control the behavior of the
  SATA Phy, but in typical Intel fashion the specification is seriously
  lacking on how events such as hot-plug are handled based on what state
  the phy is in.

  Previously we were looking for phy transition events while holding
  the port in the RESET state (DET=1, SUD=1), which worked up till this
  point.  But it doesn't work with AMD's SB850-based AHCI.

  Now we are attempting to do the same thing with the port in
  the SPIN-UP/NORMAL state (DET=0, SUD=1).

* The AHCI documentation wants us to use the LISTEN mode (DET=0, SUD=0)
  and get a SERR.DIAG.X event for hot-plug but this doesn't seem to work
  very reliably.  In fact, 10.10.4 is ambiguous for the case
  where Staggered-spin-up is not supported since SUD is wired to '1'
  in that case (making LISTEN mode impossible).

diff --git a/sys/dev/disk/ahci/ahci.c b/sys/dev/disk/ahci/ahci.c
index 1797530..218231b 100644 (file)
--- a/sys/dev/disk/ahci/ahci.c
+++ b/sys/dev/disk/ahci/ahci.c
@@ -1666,44 +1666,39 @@ ahci_port_hardstop(struct ahci_port *ap)
        }
 
        /*
-        * 10.10.3 DET must be set to 0 before setting SUD to 0.
         * 10.10.1 place us in the Listen state.
         *
-        * Deactivating SUD only applies if the controller supports SUD.
+        * 10.10.3 DET must be set to 0 and found to be 0 before
+        * setting SUD to 0.
+        *
+        * Deactivating SUD only applies if the controller supports SUD, it
+        * is a bit unclear what happens w/regards to detecting hotplug
+        * if it doesn't.
         */
-       ahci_pwrite(ap, AHCI_PREG_SCTL, AHCI_PREG_SCTL_IPM_DISABLED);
-       ahci_os_sleep(1);
-       if (cmd & AHCI_PREG_CMD_SUD) {
-               cmd &= ~AHCI_PREG_CMD_SUD;
-               ahci_pwrite(ap, AHCI_PREG_CMD, cmd);
-       }
-       ahci_os_sleep(1);
+       r = AHCI_PREG_SCTL_IPM_DISABLED |
+           AHCI_PREG_SCTL_SPM_DISABLED;
+       ahci_pwrite(ap, AHCI_PREG_SCTL, r);
+       ahci_os_sleep(10);
+       cmd &= ~AHCI_PREG_CMD_SUD;
+       ahci_pwrite(ap, AHCI_PREG_CMD, cmd);
+       ahci_os_sleep(10);
 
        /*
-        * Transition su to the spin-up state.  HVA shall send COMRESET and
-        * begin initialization sequence (whatever that means).
+        * 10.10.1
+        *
+        * Transition su to the spin-up state.  HBA shall send COMRESET and
+        * begin initialization sequence (whatever that means).  Presumably
+        * this is edge-triggered.  Following the spin-up state the HBA
+        * will automatically transition to the Normal state.
         *
         * This only applies if the controller supports SUD.
         * NEVER use AHCI_PREG_DET_DISABLE.
         */
-       cmd |= AHCI_PREG_CMD_POD | AHCI_PREG_CMD_SUD;
-       cmd |= AHCI_PREG_CMD_ICC_ACTIVE;
+       cmd |= AHCI_PREG_CMD_POD |
+              AHCI_PREG_CMD_SUD |
+              AHCI_PREG_CMD_ICC_ACTIVE;
        ahci_pwrite(ap, AHCI_PREG_CMD, cmd);
-       ahci_os_sleep(1);
-
-       /*
-        * Transition us to the Reset state.  Theoretically we send a
-        * continuous stream of COMRESETs in this state.
-        */
-       r = AHCI_PREG_SCTL_IPM_DISABLED | AHCI_PREG_SCTL_DET_INIT;
-       if (AhciForceGen1 & (1 << ap->ap_num)) {
-               kprintf("%s: Force 1.5Gbits\n", PORTNAME(ap));
-               r |= AHCI_PREG_SCTL_SPD_GEN1;
-       } else {
-               r |= AHCI_PREG_SCTL_SPD_ANY;
-       }
-       ahci_pwrite(ap, AHCI_PREG_SCTL, r);
-       ahci_os_sleep(1);
+       ahci_os_sleep(10);
 
        /*
         * Flush SERR_DIAG_X so the TFD can update.
@@ -1755,19 +1750,38 @@ ahci_port_hardstop(struct ahci_port *ap)
        }
 
        /*
-        * Leave us in COMRESET (both SUD and INIT active), the HBA should
-        * hopefully send us a DIAG_X-related interrupt if it receives
-        * a COMINIT, and if not that then at least a Phy transition
-        * interrupt.
+        * Hot-plug device detection should work at this point.  e.g. on
+        * AMD chipsets Spin-Up/Normal state is sufficient for hot-plug
+        * detection and entering RESET (continuous COMRESET by setting INIT)
+        * will actually prevent hot-plug detection from working properly.
         *
-        * If we transition INIT from 1->0 to begin the initalization
-        * sequence it is unclear if that sequence will remain active
-        * until the next device insertion.
-        *
-        * If we go back to the listen state it is unclear if the
-        * device will actually send us a COMINIT, since we aren't
-        * sending any COMRESET's
+        * There may be cases where this will fail to work, I have some
+        * additional code to place the HBA in RESET (send continuous
+        * COMRESET) and hopefully get DIAG.X or other events when something
+        * is plugged in.  Unfortunately this isn't universal and can
+        * also prevent events from generating interrupts.
+        */
+
+#if 0
+       /*
+        * Transition us to the Reset state.  Theoretically we send a
+        * continuous stream of COMRESETs in this state.
         */
+       r |= AHCI_PREG_SCTL_DET_INIT;
+       if (AhciForceGen1 & (1 << ap->ap_num)) {
+               kprintf("%s: Force 1.5Gbits\n", PORTNAME(ap));
+               r |= AHCI_PREG_SCTL_SPD_GEN1;
+       } else {
+               r |= AHCI_PREG_SCTL_SPD_ANY;
+       }
+       ahci_pwrite(ap, AHCI_PREG_SCTL, r);
+       ahci_os_sleep(10);
+
+       /*
+        * Flush SERR_DIAG_X so the TFD can update.
+        */
+       ahci_flush_tfd(ap);
+#endif
        /* NOP */
 }
 
@@ -2726,10 +2740,8 @@ finish_error:
                 * chipsets do not mask PCS/PRCS internally during reset
                 * sequences.
                 */
-               if (ap->ap_flags & AP_F_IN_RESET) {
-                       kprintf("S");
+               if (ap->ap_flags & AP_F_IN_RESET)
                        goto skip_pcs;
-               }
 
                if (ap->ap_probe == ATA_PROBE_NEED_INIT ||
                    ap->ap_probe == ATA_PROBE_NEED_HARD_RESET) {