[Qemu-devel] [PULL 18/65] libqos/ahci: create libqos/ahci.c

[Stefan Hajnoczi <stefanha@redhat.com>]

From: John Snow <jsnow@redhat.com>

With global state removed, code responsible for booting up,
verifying, and initializing the AHCI HBA is extracted and
inserted into libqos/ahci.c, which would allow for other
qtests in the future to quickly grab a meaningfully initialized
reference to an AHCI HBA.

Even without other users, functionalizing and isolating the code
assists future AHCI tests that exercise Q35 migration.

For now, libqos/ahci.o will be PC-only, but can be expanded into
something arch-agnostic in the future, if needed.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1421698563-6977-16-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 tests/Makefile      |   1 +
 tests/ahci-test.c   | 225 -------------------------------------------
 tests/libqos/ahci.c | 269 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/libqos/ahci.h |  11 ++-
 4 files changed, 280 insertions(+), 226 deletions(-)
 create mode 100644 tests/libqos/ahci.c

diff --git a/tests/Makefile b/tests/Makefile
index 415498c..53a4c30 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -310,6 +310,7 @@ libqos-obj-y = tests/libqos/pci.o tests/libqos/fw_cfg.o tests/libqos/malloc.o
 libqos-obj-y += tests/libqos/i2c.o tests/libqos/libqos.o
 libqos-pc-obj-y = $(libqos-obj-y) tests/libqos/pci-pc.o
 libqos-pc-obj-y += tests/libqos/malloc-pc.o tests/libqos/libqos-pc.o
+libqos-pc-obj-y += tests/libqos/ahci.o
 libqos-omap-obj-y = $(libqos-obj-y) tests/libqos/i2c-omap.o
 libqos-virtio-obj-y = $(libqos-obj-y) $(libqos-pc-obj-y) tests/libqos/virtio.o tests/libqos/virtio-pci.o
 libqos-usb-obj-y = $(libqos-pc-obj-y) tests/libqos/usb.o
diff --git a/tests/ahci-test.c b/tests/ahci-test.c
index b527e13..fca33d2 100644
--- a/tests/ahci-test.c
+++ b/tests/ahci-test.c
@@ -47,10 +47,6 @@ static char tmp_path[] = "/tmp/qtest.XXXXXX";
 static bool ahci_pedantic;
 
 /*** Function Declarations ***/
-static QPCIDevice *get_ahci_device(uint32_t *fingerprint);
-static void start_ahci_device(AHCIQState *ahci);
-static void free_ahci_device(QPCIDevice *dev);
-
 static void ahci_test_port_spec(AHCIQState *ahci, uint8_t port);
 static void ahci_test_pci_spec(AHCIQState *ahci);
 static void ahci_test_pci_caps(AHCIQState *ahci, uint16_t header,
@@ -72,51 +68,6 @@ static void string_bswap16(uint16_t *s, size_t bytes)
     }
 }
 
-static uint64_t ahci_alloc(AHCIQState *ahci, size_t bytes)
-{
-    return qmalloc(ahci->parent, bytes);
-}
-
-/**
- * Locate, verify, and return a handle to the AHCI device.
- */
-static QPCIDevice *get_ahci_device(uint32_t *fingerprint)
-{
-    QPCIDevice *ahci;
-    uint32_t ahci_fingerprint;
-    QPCIBus *pcibus;
-
-    pcibus = qpci_init_pc();
-
-    /* Find the AHCI PCI device and verify it's the right one. */
-    ahci = qpci_device_find(pcibus, QPCI_DEVFN(0x1F, 0x02));
-    g_assert(ahci != NULL);
-
-    ahci_fingerprint = qpci_config_readl(ahci, PCI_VENDOR_ID);
-
-    switch (ahci_fingerprint) {
-    case AHCI_INTEL_ICH9:
-        break;
-    default:
-        /* Unknown device. */
-        g_assert_not_reached();
-    }
-
-    if (fingerprint) {
-        *fingerprint = ahci_fingerprint;
-    }
-    return ahci;
-}
-
-static void free_ahci_device(QPCIDevice *dev)
-{
-    QPCIBus *pcibus = dev ? dev->bus : NULL;
-
-    /* libqos doesn't have a function for this, so free it manually */
-    g_free(dev);
-    qpci_free_pc(pcibus);
-}
-
 /*** Test Setup & Teardown ***/
 
 /**
@@ -153,182 +104,6 @@ static void ahci_shutdown(AHCIQState *ahci)
     qtest_shutdown(qs);
 }
 
-/*** Logical Device Initialization ***/
-
-/**
- * Start the PCI device and sanity-check default operation.
- */
-static void ahci_pci_enable(AHCIQState *ahci)
-{
-    uint8_t reg;
-
-    start_ahci_device(ahci);
-
-    switch (ahci->fingerprint) {
-    case AHCI_INTEL_ICH9:
-        /* ICH9 has a register at PCI 0x92 that
-         * acts as a master port enabler mask. */
-        reg = qpci_config_readb(ahci->dev, 0x92);
-        reg |= 0x3F;
-        qpci_config_writeb(ahci->dev, 0x92, reg);
-        /* 0...0111111b -- bit significant, ports 0-5 enabled. */
-        ASSERT_BIT_SET(qpci_config_readb(ahci->dev, 0x92), 0x3F);
-        break;
-    }
-
-}
-
-/**
- * Map BAR5/ABAR, and engage the PCI device.
- */
-static void start_ahci_device(AHCIQState *ahci)
-{
-    /* Map AHCI's ABAR (BAR5) */
-    ahci->hba_base = qpci_iomap(ahci->dev, 5, &ahci->barsize);
-
-    /* turns on pci.cmd.iose, pci.cmd.mse and pci.cmd.bme */
-    qpci_device_enable(ahci->dev);
-}
-
-/**
- * Test and initialize the AHCI's HBA memory areas.
- * Initialize and start any ports with devices attached.
- * Bring the HBA into the idle state.
- */
-static void ahci_hba_enable(AHCIQState *ahci)
-{
-    /* Bits of interest in this section:
-     * GHC.AE     Global Host Control / AHCI Enable
-     * PxCMD.ST   Port Command: Start
-     * PxCMD.SUD  "Spin Up Device"
-     * PxCMD.POD  "Power On Device"
-     * PxCMD.FRE  "FIS Receive Enable"
-     * PxCMD.FR   "FIS Receive Running"
-     * PxCMD.CR   "Command List Running"
-     */
-    uint32_t reg, ports_impl;
-    uint16_t i;
-    uint8_t num_cmd_slots;
-
-    g_assert(ahci != NULL);
-
-    /* Set GHC.AE to 1 */
-    ahci_set(ahci, AHCI_GHC, AHCI_GHC_AE);
-    reg = ahci_rreg(ahci, AHCI_GHC);
-    ASSERT_BIT_SET(reg, AHCI_GHC_AE);
-
-    /* Cache CAP and CAP2. */
-    ahci->cap = ahci_rreg(ahci, AHCI_CAP);
-    ahci->cap2 = ahci_rreg(ahci, AHCI_CAP2);
-
-    /* Read CAP.NCS, how many command slots do we have? */
-    num_cmd_slots = ((ahci->cap & AHCI_CAP_NCS) >> ctzl(AHCI_CAP_NCS)) + 1;
-    g_test_message("Number of Command Slots: %u", num_cmd_slots);
-
-    /* Determine which ports are implemented. */
-    ports_impl = ahci_rreg(ahci, AHCI_PI);
-
-    for (i = 0; ports_impl; ports_impl >>= 1, ++i) {
-        if (!(ports_impl & 0x01)) {
-            continue;
-        }
-
-        g_test_message("Initializing port %u", i);
-
-        reg = ahci_px_rreg(ahci, i, AHCI_PX_CMD);
-        if (BITCLR(reg, AHCI_PX_CMD_ST | AHCI_PX_CMD_CR |
-                   AHCI_PX_CMD_FRE | AHCI_PX_CMD_FR)) {
-            g_test_message("port is idle");
-        } else {
-            g_test_message("port needs to be idled");
-            ahci_px_clr(ahci, i, AHCI_PX_CMD,
-                        (AHCI_PX_CMD_ST | AHCI_PX_CMD_FRE));
-            /* The port has 500ms to disengage. */
-            usleep(500000);
-            reg = ahci_px_rreg(ahci, i, AHCI_PX_CMD);
-            ASSERT_BIT_CLEAR(reg, AHCI_PX_CMD_CR);
-            ASSERT_BIT_CLEAR(reg, AHCI_PX_CMD_FR);
-            g_test_message("port is now idle");
-            /* The spec does allow for possibly needing a PORT RESET
-             * or HBA reset if we fail to idle the port. */
-        }
-
-        /* Allocate Memory for the Command List Buffer & FIS Buffer */
-        /* PxCLB space ... 0x20 per command, as in 4.2.2 p 36 */
-        ahci->port[i].clb = ahci_alloc(ahci, num_cmd_slots * 0x20);
-        qmemset(ahci->port[i].clb, 0x00, 0x100);
-        g_test_message("CLB: 0x%08lx", ahci->port[i].clb);
-        ahci_px_wreg(ahci, i, AHCI_PX_CLB, ahci->port[i].clb);
-        g_assert_cmphex(ahci->port[i].clb, ==,
-                        ahci_px_rreg(ahci, i, AHCI_PX_CLB));
-
-        /* PxFB space ... 0x100, as in 4.2.1 p 35 */
-        ahci->port[i].fb = ahci_alloc(ahci, 0x100);
-        qmemset(ahci->port[i].fb, 0x00, 0x100);
-        g_test_message("FB: 0x%08lx", ahci->port[i].fb);
-        ahci_px_wreg(ahci, i, AHCI_PX_FB, ahci->port[i].fb);
-        g_assert_cmphex(ahci->port[i].fb, ==,
-                        ahci_px_rreg(ahci, i, AHCI_PX_FB));
-
-        /* Clear PxSERR, PxIS, then IS.IPS[x] by writing '1's. */
-        ahci_px_wreg(ahci, i, AHCI_PX_SERR, 0xFFFFFFFF);
-        ahci_px_wreg(ahci, i, AHCI_PX_IS, 0xFFFFFFFF);
-        ahci_wreg(ahci, AHCI_IS, (1 << i));
-
-        /* Verify Interrupts Cleared */
-        reg = ahci_px_rreg(ahci, i, AHCI_PX_SERR);
-        g_assert_cmphex(reg, ==, 0);
-
-        reg = ahci_px_rreg(ahci, i, AHCI_PX_IS);
-        g_assert_cmphex(reg, ==, 0);
-
-        reg = ahci_rreg(ahci, AHCI_IS);
-        ASSERT_BIT_CLEAR(reg, (1 << i));
-
-        /* Enable All Interrupts: */
-        ahci_px_wreg(ahci, i, AHCI_PX_IE, 0xFFFFFFFF);
-        reg = ahci_px_rreg(ahci, i, AHCI_PX_IE);
-        g_assert_cmphex(reg, ==, ~((uint32_t)AHCI_PX_IE_RESERVED));
-
-        /* Enable the FIS Receive Engine. */
-        ahci_px_set(ahci, i, AHCI_PX_CMD, AHCI_PX_CMD_FRE);
-        reg = ahci_px_rreg(ahci, i, AHCI_PX_CMD);
-        ASSERT_BIT_SET(reg, AHCI_PX_CMD_FR);
-
-        /* AHCI 1.3 spec: if !STS.BSY, !STS.DRQ and PxSSTS.DET indicates
-         * physical presence, a device is present and may be started. However,
-         * PxSERR.DIAG.X /may/ need to be cleared a priori. */
-        reg = ahci_px_rreg(ahci, i, AHCI_PX_SERR);
-        if (BITSET(reg, AHCI_PX_SERR_DIAG_X)) {
-            ahci_px_set(ahci, i, AHCI_PX_SERR, AHCI_PX_SERR_DIAG_X);
-        }
-
-        reg = ahci_px_rreg(ahci, i, AHCI_PX_TFD);
-        if (BITCLR(reg, AHCI_PX_TFD_STS_BSY | AHCI_PX_TFD_STS_DRQ)) {
-            reg = ahci_px_rreg(ahci, i, AHCI_PX_SSTS);
-            if ((reg & AHCI_PX_SSTS_DET) == SSTS_DET_ESTABLISHED) {
-                /* Device Found: set PxCMD.ST := 1 */
-                ahci_px_set(ahci, i, AHCI_PX_CMD, AHCI_PX_CMD_ST);
-                ASSERT_BIT_SET(ahci_px_rreg(ahci, i, AHCI_PX_CMD),
-                               AHCI_PX_CMD_CR);
-                g_test_message("Started Device %u", i);
-            } else if ((reg & AHCI_PX_SSTS_DET)) {
-                /* Device present, but in some unknown state. */
-                g_assert_not_reached();
-            }
-        }
-    }
-
-    /* Enable GHC.IE */
-    ahci_set(ahci, AHCI_GHC, AHCI_GHC_IE);
-    reg = ahci_rreg(ahci, AHCI_GHC);
-    ASSERT_BIT_SET(reg, AHCI_GHC_IE);
-
-    /* TODO: The device should now be idling and waiting for commands.
-     * In the future, a small test-case to inspect the Register D2H FIS
-     * and clear the initial interrupts might be good. */
-}
-
 /*** Specification Adherence Tests ***/
 
 /**
diff --git a/tests/libqos/ahci.c b/tests/libqos/ahci.c
new file mode 100644
index 0000000..3056fb1
--- /dev/null
+++ b/tests/libqos/ahci.c
@@ -0,0 +1,269 @@
+/*
+ * libqos AHCI functions
+ *
+ * Copyright (c) 2014 John Snow <jsnow@redhat.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <glib.h>
+
+#include "libqtest.h"
+#include "libqos/ahci.h"
+#include "libqos/pci-pc.h"
+
+#include "qemu-common.h"
+#include "qemu/host-utils.h"
+
+#include "hw/pci/pci_ids.h"
+#include "hw/pci/pci_regs.h"
+
+/**
+ * Allocate space in the guest using information in the AHCIQState object.
+ */
+uint64_t ahci_alloc(AHCIQState *ahci, size_t bytes)
+{
+    g_assert(ahci);
+    g_assert(ahci->parent);
+    return qmalloc(ahci->parent, bytes);
+}
+
+void ahci_free(AHCIQState *ahci, uint64_t addr)
+{
+    g_assert(ahci);
+    g_assert(ahci->parent);
+    qfree(ahci->parent, addr);
+}
+
+/**
+ * Locate, verify, and return a handle to the AHCI device.
+ */
+QPCIDevice *get_ahci_device(uint32_t *fingerprint)
+{
+    QPCIDevice *ahci;
+    uint32_t ahci_fingerprint;
+    QPCIBus *pcibus;
+
+    pcibus = qpci_init_pc();
+
+    /* Find the AHCI PCI device and verify it's the right one. */
+    ahci = qpci_device_find(pcibus, QPCI_DEVFN(0x1F, 0x02));
+    g_assert(ahci != NULL);
+
+    ahci_fingerprint = qpci_config_readl(ahci, PCI_VENDOR_ID);
+
+    switch (ahci_fingerprint) {
+    case AHCI_INTEL_ICH9:
+        break;
+    default:
+        /* Unknown device. */
+        g_assert_not_reached();
+    }
+
+    if (fingerprint) {
+        *fingerprint = ahci_fingerprint;
+    }
+    return ahci;
+}
+
+void free_ahci_device(QPCIDevice *dev)
+{
+    QPCIBus *pcibus = dev ? dev->bus : NULL;
+
+    /* libqos doesn't have a function for this, so free it manually */
+    g_free(dev);
+    qpci_free_pc(pcibus);
+}
+
+/*** Logical Device Initialization ***/
+
+/**
+ * Start the PCI device and sanity-check default operation.
+ */
+void ahci_pci_enable(AHCIQState *ahci)
+{
+    uint8_t reg;
+
+    start_ahci_device(ahci);
+
+    switch (ahci->fingerprint) {
+    case AHCI_INTEL_ICH9:
+        /* ICH9 has a register at PCI 0x92 that
+         * acts as a master port enabler mask. */
+        reg = qpci_config_readb(ahci->dev, 0x92);
+        reg |= 0x3F;
+        qpci_config_writeb(ahci->dev, 0x92, reg);
+        /* 0...0111111b -- bit significant, ports 0-5 enabled. */
+        ASSERT_BIT_SET(qpci_config_readb(ahci->dev, 0x92), 0x3F);
+        break;
+    }
+
+}
+
+/**
+ * Map BAR5/ABAR, and engage the PCI device.
+ */
+void start_ahci_device(AHCIQState *ahci)
+{
+    /* Map AHCI's ABAR (BAR5) */
+    ahci->hba_base = qpci_iomap(ahci->dev, 5, &ahci->barsize);
+    g_assert(ahci->hba_base);
+
+    /* turns on pci.cmd.iose, pci.cmd.mse and pci.cmd.bme */
+    qpci_device_enable(ahci->dev);
+}
+
+/**
+ * Test and initialize the AHCI's HBA memory areas.
+ * Initialize and start any ports with devices attached.
+ * Bring the HBA into the idle state.
+ */
+void ahci_hba_enable(AHCIQState *ahci)
+{
+    /* Bits of interest in this section:
+     * GHC.AE     Global Host Control / AHCI Enable
+     * PxCMD.ST   Port Command: Start
+     * PxCMD.SUD  "Spin Up Device"
+     * PxCMD.POD  "Power On Device"
+     * PxCMD.FRE  "FIS Receive Enable"
+     * PxCMD.FR   "FIS Receive Running"
+     * PxCMD.CR   "Command List Running"
+     */
+    uint32_t reg, ports_impl;
+    uint16_t i;
+    uint8_t num_cmd_slots;
+
+    g_assert(ahci != NULL);
+
+    /* Set GHC.AE to 1 */
+    ahci_set(ahci, AHCI_GHC, AHCI_GHC_AE);
+    reg = ahci_rreg(ahci, AHCI_GHC);
+    ASSERT_BIT_SET(reg, AHCI_GHC_AE);
+
+    /* Cache CAP and CAP2. */
+    ahci->cap = ahci_rreg(ahci, AHCI_CAP);
+    ahci->cap2 = ahci_rreg(ahci, AHCI_CAP2);
+
+    /* Read CAP.NCS, how many command slots do we have? */
+    num_cmd_slots = ((ahci->cap & AHCI_CAP_NCS) >> ctzl(AHCI_CAP_NCS)) + 1;
+    g_test_message("Number of Command Slots: %u", num_cmd_slots);
+
+    /* Determine which ports are implemented. */
+    ports_impl = ahci_rreg(ahci, AHCI_PI);
+
+    for (i = 0; ports_impl; ports_impl >>= 1, ++i) {
+        if (!(ports_impl & 0x01)) {
+            continue;
+        }
+
+        g_test_message("Initializing port %u", i);
+
+        reg = ahci_px_rreg(ahci, i, AHCI_PX_CMD);
+        if (BITCLR(reg, AHCI_PX_CMD_ST | AHCI_PX_CMD_CR |
+                   AHCI_PX_CMD_FRE | AHCI_PX_CMD_FR)) {
+            g_test_message("port is idle");
+        } else {
+            g_test_message("port needs to be idled");
+            ahci_px_clr(ahci, i, AHCI_PX_CMD,
+                        (AHCI_PX_CMD_ST | AHCI_PX_CMD_FRE));
+            /* The port has 500ms to disengage. */
+            usleep(500000);
+            reg = ahci_px_rreg(ahci, i, AHCI_PX_CMD);
+            ASSERT_BIT_CLEAR(reg, AHCI_PX_CMD_CR);
+            ASSERT_BIT_CLEAR(reg, AHCI_PX_CMD_FR);
+            g_test_message("port is now idle");
+            /* The spec does allow for possibly needing a PORT RESET
+             * or HBA reset if we fail to idle the port. */
+        }
+
+        /* Allocate Memory for the Command List Buffer & FIS Buffer */
+        /* PxCLB space ... 0x20 per command, as in 4.2.2 p 36 */
+        ahci->port[i].clb = ahci_alloc(ahci, num_cmd_slots * 0x20);
+        qmemset(ahci->port[i].clb, 0x00, 0x100);
+        g_test_message("CLB: 0x%08lx", ahci->port[i].clb);
+        ahci_px_wreg(ahci, i, AHCI_PX_CLB, ahci->port[i].clb);
+        g_assert_cmphex(ahci->port[i].clb, ==,
+                        ahci_px_rreg(ahci, i, AHCI_PX_CLB));
+
+        /* PxFB space ... 0x100, as in 4.2.1 p 35 */
+        ahci->port[i].fb = ahci_alloc(ahci, 0x100);
+        qmemset(ahci->port[i].fb, 0x00, 0x100);
+        g_test_message("FB: 0x%08lx", ahci->port[i].fb);
+        ahci_px_wreg(ahci, i, AHCI_PX_FB, ahci->port[i].fb);
+        g_assert_cmphex(ahci->port[i].fb, ==,
+                        ahci_px_rreg(ahci, i, AHCI_PX_FB));
+
+        /* Clear PxSERR, PxIS, then IS.IPS[x] by writing '1's. */
+        ahci_px_wreg(ahci, i, AHCI_PX_SERR, 0xFFFFFFFF);
+        ahci_px_wreg(ahci, i, AHCI_PX_IS, 0xFFFFFFFF);
+        ahci_wreg(ahci, AHCI_IS, (1 << i));
+
+        /* Verify Interrupts Cleared */
+        reg = ahci_px_rreg(ahci, i, AHCI_PX_SERR);
+        g_assert_cmphex(reg, ==, 0);
+
+        reg = ahci_px_rreg(ahci, i, AHCI_PX_IS);
+        g_assert_cmphex(reg, ==, 0);
+
+        reg = ahci_rreg(ahci, AHCI_IS);
+        ASSERT_BIT_CLEAR(reg, (1 << i));
+
+        /* Enable All Interrupts: */
+        ahci_px_wreg(ahci, i, AHCI_PX_IE, 0xFFFFFFFF);
+        reg = ahci_px_rreg(ahci, i, AHCI_PX_IE);
+        g_assert_cmphex(reg, ==, ~((uint32_t)AHCI_PX_IE_RESERVED));
+
+        /* Enable the FIS Receive Engine. */
+        ahci_px_set(ahci, i, AHCI_PX_CMD, AHCI_PX_CMD_FRE);
+        reg = ahci_px_rreg(ahci, i, AHCI_PX_CMD);
+        ASSERT_BIT_SET(reg, AHCI_PX_CMD_FR);
+
+        /* AHCI 1.3 spec: if !STS.BSY, !STS.DRQ and PxSSTS.DET indicates
+         * physical presence, a device is present and may be started. However,
+         * PxSERR.DIAG.X /may/ need to be cleared a priori. */
+        reg = ahci_px_rreg(ahci, i, AHCI_PX_SERR);
+        if (BITSET(reg, AHCI_PX_SERR_DIAG_X)) {
+            ahci_px_set(ahci, i, AHCI_PX_SERR, AHCI_PX_SERR_DIAG_X);
+        }
+
+        reg = ahci_px_rreg(ahci, i, AHCI_PX_TFD);
+        if (BITCLR(reg, AHCI_PX_TFD_STS_BSY | AHCI_PX_TFD_STS_DRQ)) {
+            reg = ahci_px_rreg(ahci, i, AHCI_PX_SSTS);
+            if ((reg & AHCI_PX_SSTS_DET) == SSTS_DET_ESTABLISHED) {
+                /* Device Found: set PxCMD.ST := 1 */
+                ahci_px_set(ahci, i, AHCI_PX_CMD, AHCI_PX_CMD_ST);
+                ASSERT_BIT_SET(ahci_px_rreg(ahci, i, AHCI_PX_CMD),
+                               AHCI_PX_CMD_CR);
+                g_test_message("Started Device %u", i);
+            } else if ((reg & AHCI_PX_SSTS_DET)) {
+                /* Device present, but in some unknown state. */
+                g_assert_not_reached();
+            }
+        }
+    }
+
+    /* Enable GHC.IE */
+    ahci_set(ahci, AHCI_GHC, AHCI_GHC_IE);
+    reg = ahci_rreg(ahci, AHCI_GHC);
+    ASSERT_BIT_SET(reg, AHCI_GHC_IE);
+
+    /* TODO: The device should now be idling and waiting for commands.
+     * In the future, a small test-case to inspect the Register D2H FIS
+     * and clear the initial interrupts might be good. */
+}
diff --git a/tests/libqos/ahci.h b/tests/libqos/ahci.h
index 72c39bc..77f2055 100644
--- a/tests/libqos/ahci.h
+++ b/tests/libqos/ahci.h
@@ -28,7 +28,7 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <stdbool.h>
-
+#include "libqos/libqos.h"
 #include "libqos/pci.h"
 #include "libqos/malloc-pc.h"
 
@@ -423,4 +423,13 @@ static inline void ahci_px_clr(AHCIQState *ahci, uint8_t port,
                  ahci_px_rreg(ahci, port, reg_num) & ~mask);
 }
 
+/*** Prototypes ***/
+uint64_t ahci_alloc(AHCIQState *ahci, size_t bytes);
+void ahci_free(AHCIQState *ahci, uint64_t addr);
+QPCIDevice *get_ahci_device(uint32_t *fingerprint);
+void free_ahci_device(QPCIDevice *dev);
+void ahci_pci_enable(AHCIQState *ahci);
+void start_ahci_device(AHCIQState *ahci);
+void ahci_hba_enable(AHCIQState *ahci);
+
 #endif
-- 
2.1.0