[PATCH 2/2] ppc/pnv: Implement ADU access to LPC space

[Nicholas Piggin <npiggin@gmail.com>]

One of the functions of the ADU is indirect memory access engines that
send and receive data via ADU registers.

This implements the ADU LPC memory access functionality sufficiently
for IBM proprietary firmware to access the UART and print characters
to the serial port as it does on real hardware.

This requires a linkage between adu and lpc, which allows adu to
perform memory access in the lpc space.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 include/hw/ppc/pnv_adu.h |  7 ++++
 include/hw/ppc/pnv_lpc.h |  5 +++
 hw/ppc/pnv.c             |  4 ++
 hw/ppc/pnv_adu.c         | 91 ++++++++++++++++++++++++++++++++++++++++
 hw/ppc/pnv_lpc.c         | 12 +++---
 5 files changed, 113 insertions(+), 6 deletions(-)

diff --git a/include/hw/ppc/pnv_adu.h b/include/hw/ppc/pnv_adu.h
index 9dc91857a9..b7b5d1bb21 100644
--- a/include/hw/ppc/pnv_adu.h
+++ b/include/hw/ppc/pnv_adu.h
@@ -10,6 +10,7 @@
 #define PPC_PNV_ADU_H
 
 #include "hw/ppc/pnv.h"
+#include "hw/ppc/pnv_lpc.h"
 #include "hw/qdev-core.h"
 
 #define TYPE_PNV_ADU "pnv-adu"
@@ -19,6 +20,12 @@ OBJECT_DECLARE_TYPE(PnvADU, PnvADUClass, PNV_ADU)
 struct PnvADU {
     DeviceState xd;
 
+    /* LPCMC (LPC Master Controller) access engine */
+    PnvLpcController *lpc;
+    uint64_t     lpc_base_reg;
+    uint64_t     lpc_cmd_reg;
+    uint64_t     lpc_data_reg;
+
     MemoryRegion xscom_regs;
 };
 
diff --git a/include/hw/ppc/pnv_lpc.h b/include/hw/ppc/pnv_lpc.h
index 5d22c45570..016e2998a8 100644
--- a/include/hw/ppc/pnv_lpc.h
+++ b/include/hw/ppc/pnv_lpc.h
@@ -94,6 +94,11 @@ struct PnvLpcClass {
     DeviceRealize parent_realize;
 };
 
+bool pnv_opb_lpc_read(PnvLpcController *lpc, uint32_t addr,
+                      uint8_t *data, int sz);
+bool pnv_opb_lpc_write(PnvLpcController *lpc, uint32_t addr,
+                       uint8_t *data, int sz);
+
 ISABus *pnv_lpc_isa_create(PnvLpcController *lpc, bool use_cpld, Error **errp);
 int pnv_dt_lpc(PnvChip *chip, void *fdt, int root_offset,
                uint64_t lpcm_addr, uint64_t lpcm_size);
diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
index 5869aac89a..eb9dbc62dd 100644
--- a/hw/ppc/pnv.c
+++ b/hw/ppc/pnv.c
@@ -1642,6 +1642,8 @@ static void pnv_chip_power9_realize(DeviceState *dev, Error **errp)
     }
 
     /* ADU */
+    object_property_set_link(OBJECT(&chip9->adu), "lpc", OBJECT(&chip9->lpc),
+                             &error_abort);
     if (!qdev_realize(DEVICE(&chip9->adu), NULL, errp)) {
         return;
     }
@@ -1908,6 +1910,8 @@ static void pnv_chip_power10_realize(DeviceState *dev, Error **errp)
     }
 
     /* ADU */
+    object_property_set_link(OBJECT(&chip10->adu), "lpc", OBJECT(&chip10->lpc),
+                             &error_abort);
     if (!qdev_realize(DEVICE(&chip10->adu), NULL, errp)) {
         return;
     }
diff --git a/hw/ppc/pnv_adu.c b/hw/ppc/pnv_adu.c
index 5bd33a3841..d5570c23e2 100644
--- a/hw/ppc/pnv_adu.c
+++ b/hw/ppc/pnv_adu.c
@@ -21,9 +21,15 @@
 #include "hw/ppc/pnv.h"
 #include "hw/ppc/pnv_adu.h"
 #include "hw/ppc/pnv_chip.h"
+#include "hw/ppc/pnv_lpc.h"
 #include "hw/ppc/pnv_xscom.h"
 #include "trace.h"
 
+#define ADU_LPC_BASE_REG     0x40
+#define ADU_LPC_CMD_REG      0x41
+#define ADU_LPC_DATA_REG     0x42
+#define ADU_LPC_STATUS_REG   0x43
+
 static uint64_t pnv_adu_xscom_read(void *opaque, hwaddr addr, unsigned width)
 {
     PnvADU *adu = PNV_ADU(opaque);
@@ -35,6 +41,24 @@ static uint64_t pnv_adu_xscom_read(void *opaque, hwaddr addr, unsigned width)
     case 0x12:     /* log register */
     case 0x13:     /* error register */
         break;
+    case ADU_LPC_BASE_REG:
+        /*
+         * LPC Address Map in Pervasive ADU Workbook
+         *
+         * return PNV10_LPCM_BASE(chip) & PPC_BITMASK(8, 31);
+         * XXX: implement as class property, or get from LPC?
+         */
+        qemu_log_mask(LOG_UNIMP, "ADU: LPC_BASE_REG is not implemented\n");
+        break;
+    case ADU_LPC_CMD_REG:
+        val = adu->lpc_cmd_reg;
+        break;
+    case ADU_LPC_DATA_REG:
+        val = adu->lpc_data_reg;
+        break;
+    case ADU_LPC_STATUS_REG:
+        val = PPC_BIT(0); /* ack / done */
+        break;
 
     default:
         qemu_log_mask(LOG_UNIMP, "ADU Unimplemented read register: Ox%08x\n",
@@ -46,6 +70,26 @@ static uint64_t pnv_adu_xscom_read(void *opaque, hwaddr addr, unsigned width)
     return val;
 }
 
+static bool lpc_cmd_read(PnvADU *adu)
+{
+    return !!(adu->lpc_cmd_reg & PPC_BIT(0));
+}
+
+static bool lpc_cmd_write(PnvADU *adu)
+{
+    return !lpc_cmd_read(adu);
+}
+
+static uint32_t lpc_cmd_addr(PnvADU *adu)
+{
+    return (adu->lpc_cmd_reg & PPC_BITMASK(32, 63)) >> PPC_BIT_NR(63);
+}
+
+static uint32_t lpc_cmd_size(PnvADU *adu)
+{
+    return (adu->lpc_cmd_reg & PPC_BITMASK(5, 11)) >> PPC_BIT_NR(11);
+}
+
 static void pnv_adu_xscom_write(void *opaque, hwaddr addr, uint64_t val,
                                 unsigned width)
 {
@@ -60,6 +104,47 @@ static void pnv_adu_xscom_write(void *opaque, hwaddr addr, uint64_t val,
     case 0x13:     /* error register */
         break;
 
+    case ADU_LPC_BASE_REG:
+        qemu_log_mask(LOG_UNIMP,
+                      "ADU: Changing LPC_BASE_REG is not implemented\n");
+        break;
+
+    case ADU_LPC_CMD_REG:
+        adu->lpc_cmd_reg = val;
+        if (lpc_cmd_read(adu)) {
+            uint32_t lpc_addr = lpc_cmd_addr(adu);
+            uint32_t lpc_size = lpc_cmd_size(adu);
+            uint64_t data = 0;
+
+            pnv_opb_lpc_read(adu->lpc, lpc_addr, (void *)&data, lpc_size);
+
+            /*
+             * ADU access is performed within 8-byte aligned sectors. Smaller
+             * access sizes don't get formatted to the least significant byte,
+             * but rather appear in the data reg at the same offset as the
+             * address in memory. This shifts them into that position.
+             */
+            adu->lpc_data_reg = be64_to_cpu(data) >> ((lpc_addr & 7) * 8);
+        }
+        break;
+
+    case ADU_LPC_DATA_REG:
+        adu->lpc_data_reg = val;
+        if (lpc_cmd_write(adu)) {
+            uint32_t lpc_addr = lpc_cmd_addr(adu);
+            uint32_t lpc_size = lpc_cmd_size(adu);
+            uint64_t data;
+
+            data = cpu_to_be64(val) >> ((lpc_addr & 7) * 8); /* See above */
+            pnv_opb_lpc_write(adu->lpc, lpc_addr, (void *)&data, lpc_size);
+        }
+        break;
+
+    case ADU_LPC_STATUS_REG:
+        qemu_log_mask(LOG_UNIMP,
+                      "ADU: Changing LPC_STATUS_REG is not implemented\n");
+        break;
+
     default:
         qemu_log_mask(LOG_UNIMP, "ADU Unimplemented write register: Ox%08x\n",
                                                                      offset);
@@ -86,12 +171,18 @@ static void pnv_adu_realize(DeviceState *dev, Error **errp)
                           PNV9_XSCOM_ADU_SIZE);
 }
 
+static Property pnv_adu_properties[] = {
+    DEFINE_PROP_LINK("lpc", PnvADU, lpc, TYPE_PNV_LPC, PnvLpcController *),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
 static void pnv_adu_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = pnv_adu_realize;
     dc->desc = "PowerNV ADU";
+    device_class_set_props(dc, pnv_adu_properties);
     dc->user_creatable = false;
 }
 
diff --git a/hw/ppc/pnv_lpc.c b/hw/ppc/pnv_lpc.c
index d692858bee..743bd66fc0 100644
--- a/hw/ppc/pnv_lpc.c
+++ b/hw/ppc/pnv_lpc.c
@@ -235,16 +235,16 @@ int pnv_dt_lpc(PnvChip *chip, void *fdt, int root_offset, uint64_t lpcm_addr,
  * TODO: rework to use address_space_stq() and address_space_ldq()
  * instead.
  */
-static bool opb_read(PnvLpcController *lpc, uint32_t addr, uint8_t *data,
-                     int sz)
+bool pnv_opb_lpc_read(PnvLpcController *lpc, uint32_t addr,
+                      uint8_t *data, int sz)
 {
     /* XXX Handle access size limits and FW read caching here */
     return !address_space_read(&lpc->opb_as, addr, MEMTXATTRS_UNSPECIFIED,
                                data, sz);
 }
 
-static bool opb_write(PnvLpcController *lpc, uint32_t addr, uint8_t *data,
-                      int sz)
+bool pnv_opb_lpc_write(PnvLpcController *lpc, uint32_t addr,
+                       uint8_t *data, int sz)
 {
     /* XXX Handle access size limits here */
     return !address_space_write(&lpc->opb_as, addr, MEMTXATTRS_UNSPECIFIED,
@@ -276,7 +276,7 @@ static void pnv_lpc_do_eccb(PnvLpcController *lpc, uint64_t cmd)
     }
 
     if (cmd & ECCB_CTL_READ) {
-        success = opb_read(lpc, opb_addr, data, sz);
+        success = pnv_opb_lpc_read(lpc, opb_addr, data, sz);
         if (success) {
             lpc->eccb_stat_reg = ECCB_STAT_OP_DONE |
                     (((uint64_t)data[0]) << 24 |
@@ -293,7 +293,7 @@ static void pnv_lpc_do_eccb(PnvLpcController *lpc, uint64_t cmd)
         data[2] = lpc->eccb_data_reg >>  8;
         data[3] = lpc->eccb_data_reg;
 
-        success = opb_write(lpc, opb_addr, data, sz);
+        success = pnv_opb_lpc_write(lpc, opb_addr, data, sz);
         lpc->eccb_stat_reg = ECCB_STAT_OP_DONE;
     }
     /* XXX Which error bit (if any) to signal OPB error ? */
-- 
2.43.0