[PATCH v4 2/2] hw/cxl: Add Physical Port Control (Opcode 5102h)

[Arpit Kumar <arpit1.kumar@samsung.com>]

-added assert-deassert PERST implementation
 for physical ports (both USP and DSP's).
-assert PERST involves bg operation for holding 100ms.
-reset PPB implementation for physical ports.

Signed-off-by: Arpit Kumar <arpit1.kumar@samsung.com>
---
 hw/cxl/cxl-mailbox-utils.c                | 139 ++++++++++++++++++++++
 include/hw/cxl/cxl_device.h               |   9 ++
 include/hw/cxl/cxl_mailbox.h              |   1 +
 include/hw/pci-bridge/cxl_upstream_port.h |   1 +
 4 files changed, 150 insertions(+)

diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
index 2a104dd337..8cccb2c0ed 100644
--- a/hw/cxl/cxl-mailbox-utils.c
+++ b/hw/cxl/cxl-mailbox-utils.c
@@ -541,6 +541,120 @@ static CXLRetCode cmd_get_physical_port_state(const struct cxl_cmd *cmd,
     return CXL_MBOX_SUCCESS;
 }
 
+static void *bg_assertcb(void *opaque)
+{
+    CXLPhyPortPerst *perst = opaque;
+
+    /* holding reset phase for 100ms */
+    while (perst->asrt_time--) {
+        usleep(1000);
+    }
+    perst->issued_assert_perst = true;
+    return NULL;
+}
+
+static CXLRetCode deassert_perst(Object *obj, uint8_t pn, CXLUpstreamPort *pp)
+{
+    if (!pp->pports.perst[pn].issued_assert_perst) {
+        return CXL_MBOX_INTERNAL_ERROR;
+    }
+
+    QEMU_LOCK_GUARD(&pp->pports.perst[pn].lock);
+    resettable_release_reset(obj, RESET_TYPE_COLD);
+    pp->pports.perst[pn].issued_assert_perst = false;
+    pp->pports.pport_info[pn].link_state_flags &=
+        ~CXL_PORT_LINK_STATE_FLAG_PERST_ASSERTED;
+    pp->pports.perst[pn].asrt_time = ASSERT_WAIT_TIME_MS;
+
+    return CXL_MBOX_SUCCESS;
+}
+
+static CXLRetCode assert_perst(Object *obj, uint8_t pn, CXLUpstreamPort *pp)
+{
+    if (pp->pports.perst[pn].issued_assert_perst ||
+        pp->pports.perst[pn].asrt_time < ASSERT_WAIT_TIME_MS) {
+        return CXL_MBOX_INTERNAL_ERROR;
+    }
+
+    QEMU_LOCK_GUARD(&pp->pports.perst[pn].lock);
+    pp->pports.pport_info[pn].link_state_flags |=
+        CXL_PORT_LINK_STATE_FLAG_PERST_ASSERTED;
+    resettable_assert_reset(obj, RESET_TYPE_COLD);
+    qemu_thread_create(&pp->pports.perst[pn].asrt_thread, "assert_thread",
+        bg_assertcb, &pp->pports.perst[pn], QEMU_THREAD_DETACHED);
+
+    return CXL_MBOX_SUCCESS;
+}
+
+static struct PCIDevice *cxl_find_port_dev(uint8_t pn, CXLCCI *cci)
+{
+    CXLUpstreamPort *pp = CXL_USP(cci->d);
+    PCIBus *bus = &PCI_BRIDGE(cci->d)->sec_bus;
+
+    if (pp->pports.pport_info[pn].current_port_config_state ==
+        CXL_PORT_CONFIG_STATE_USP) {
+        return pci_bridge_get_device(bus);
+    }
+
+    if (pp->pports.pport_info[pn].current_port_config_state ==
+        CXL_PORT_CONFIG_STATE_DSP) {
+        return pcie_find_port_by_pn(bus, pn);
+    }
+    return NULL;
+}
+
+/* CXL r3.2 Section 7.6.7.1.3: Get Physical Port Control (Opcode 5102h) */
+static CXLRetCode cmd_physical_port_control(const struct cxl_cmd *cmd,
+                                            uint8_t *payload_in,
+                                            size_t len_in,
+                                            uint8_t *payload_out,
+                                            size_t *len_out,
+                                            CXLCCI *cci)
+{
+   CXLUpstreamPort *pp = CXL_USP(cci->d);
+   PCIDevice *dev;
+   uint8_t pn;
+   uint8_t ret = CXL_MBOX_SUCCESS;
+
+   struct cxl_fmapi_get_physical_port_control_req_pl {
+        uint8_t ppb_id;
+        uint8_t ports_op;
+    } QEMU_PACKED *in = (void *)payload_in;
+
+    if (len_in < sizeof(*in)) {
+        return CXL_MBOX_INVALID_PAYLOAD_LENGTH;
+    }
+
+    pn = in->ppb_id;
+    if (pp->pports.pport_info[pn].port_id != pn) {
+        return CXL_MBOX_INTERNAL_ERROR;
+    }
+
+    dev = cxl_find_port_dev(pn, cci);
+    if (!dev) {
+        return CXL_MBOX_INTERNAL_ERROR;
+    }
+
+    switch (in->ports_op) {
+    case 0:
+        ret = assert_perst(OBJECT(&dev->qdev), pn, pp);
+        break;
+    case 1:
+        ret = deassert_perst(OBJECT(&dev->qdev), pn, pp);
+        break;
+    case 2:
+        if (pp->pports.perst[pn].issued_assert_perst ||
+            pp->pports.perst[pn].asrt_time < ASSERT_WAIT_TIME_MS) {
+            return CXL_MBOX_INTERNAL_ERROR;
+        }
+        device_cold_reset(&dev->qdev);
+        break;
+    default:
+        return CXL_MBOX_INVALID_INPUT;
+    }
+    return ret;
+}
+
 /* CXL r3.1 Section 8.2.9.1.2: Background Operation Status (Opcode 0002h) */
 static CXLRetCode cmd_infostat_bg_op_sts(const struct cxl_cmd *cmd,
                                          uint8_t *payload_in,
@@ -4347,6 +4461,8 @@ static const struct cxl_cmd cxl_cmd_set_sw[256][256] = {
         cmd_identify_switch_device, 0, 0 },
     [PHYSICAL_SWITCH][GET_PHYSICAL_PORT_STATE] = { "SWITCH_PHYSICAL_PORT_STATS",
         cmd_get_physical_port_state, ~0, 0 },
+    [PHYSICAL_SWITCH][PHYSICAL_PORT_CONTROL] = { "SWITCH_PHYSICAL_PORT_CONTROL",
+        cmd_physical_port_control, 2, 0 },
     [TUNNEL][MANAGEMENT_COMMAND] = { "TUNNEL_MANAGEMENT_COMMAND",
                                      cmd_tunnel_management_cmd, ~0, 0 },
 };
@@ -4702,11 +4818,34 @@ static CXLRetCode cxl_set_phy_port_info(CXLCCI *cci)
 void cxl_initialize_mailbox_swcci(CXLCCI *cci, DeviceState *intf,
                                   DeviceState *d, size_t payload_max)
 {
+    CXLUpstreamPort *pp;
+    uint8_t pn = 0;
+
     cxl_copy_cci_commands(cci, cxl_cmd_set_sw);
     cci->d = d;
     cci->intf = intf;
     cxl_init_cci(cci, payload_max);
     cxl_set_phy_port_info(cci);
+    /* physical port control */
+    pp = CXL_USP(cci->d);
+    for (int byte_index = 0; byte_index < (CXL_MAX_PHY_PORTS / BITS_PER_BYTE);
+         byte_index++) {
+        unsigned char byte = pp->pports.active_port_bitmask[byte_index];
+
+        for (int bit_index = 0; bit_index < 8; bit_index++, pn++) {
+            if (((byte) & (1 << bit_index)) != 0) {
+                qemu_mutex_init(&pp->pports.perst[pn].lock);
+                pp->pports.perst[pn].issued_assert_perst = false;
+                /*
+                 * Assert PERST involves physical port to be in
+                 * hold reset phase for minimum 100ms. No other
+                 * physical port control requests are entertained
+                 * until Deassert PERST command.
+                 */
+                pp->pports.perst[pn].asrt_time = ASSERT_WAIT_TIME_MS;
+            }
+        }
+    }
 }
 
 void cxl_initialize_mailbox_t3(CXLCCI *cci, DeviceState *d, size_t payload_max)
diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
index 536d465f42..4d00e76983 100644
--- a/include/hw/cxl/cxl_device.h
+++ b/include/hw/cxl/cxl_device.h
@@ -130,6 +130,7 @@
                   (1 << 16))
 
 #define CXL_MAX_PHY_PORTS 256
+#define ASSERT_WAIT_TIME_MS 100 /* Assert - Deassert PERST */
 
 /* CXL r3.2 Table 7-19: Get Physical Port State Port Information Block Format */
 #define CXL_PORT_CONFIG_STATE_DISABLED           0x0
@@ -196,6 +197,14 @@ typedef struct CXLPhyPortInfo {
     uint8_t supported_ld_count;
 } QEMU_PACKED CXLPhyPortInfo;
 
+/* Assert - Deassert PERST */
+typedef struct CXLPhyPortPerst {
+    bool issued_assert_perst;
+    QemuMutex lock; /* protecting assert-deassert reset request */
+    uint64_t asrt_time;
+    QemuThread asrt_thread; /* thread for 100ms delay */
+} CXLPhyPortPerst;
+
 /* CXL r3.1 Table 8-34: Command Return Codes */
 typedef enum {
     CXL_MBOX_SUCCESS = 0x0,
diff --git a/include/hw/cxl/cxl_mailbox.h b/include/hw/cxl/cxl_mailbox.h
index 5c918c53a9..2c71dab670 100644
--- a/include/hw/cxl/cxl_mailbox.h
+++ b/include/hw/cxl/cxl_mailbox.h
@@ -88,6 +88,7 @@ enum {
     PHYSICAL_SWITCH = 0x51,
         #define IDENTIFY_SWITCH_DEVICE      0x0
         #define GET_PHYSICAL_PORT_STATE     0x1
+        #define PHYSICAL_PORT_CONTROL       0x2
     TUNNEL = 0x53,
         #define MANAGEMENT_COMMAND     0x0
     MHD = 0x55,
diff --git a/include/hw/pci-bridge/cxl_upstream_port.h b/include/hw/pci-bridge/cxl_upstream_port.h
index c6218100a2..e8f5e43faf 100644
--- a/include/hw/pci-bridge/cxl_upstream_port.h
+++ b/include/hw/pci-bridge/cxl_upstream_port.h
@@ -30,6 +30,7 @@ typedef struct CXLUpstreamPort {
         uint8_t num_ports;
         uint8_t active_port_bitmask[CXL_MAX_PHY_PORTS / BITS_PER_BYTE];
         CXLPhyPortInfo pport_info[CXL_MAX_PHY_PORTS];
+        CXLPhyPortPerst perst[CXL_MAX_PHY_PORTS];
     } pports;
 } CXLUpstreamPort;
 
-- 
2.34.1