[PATCH v2 2/2] hw/ssi: xilinx_spips: Implement basic QSPI DMA support

[Bin Meng]

From: Xuzhou Cheng <xuzhou.cheng@windriver.com>

ZynqMP QSPI supports SPI transfer using DMA mode, but currently this
is unimplemented. When QSPI is programmed to use DMA mode, QEMU will
crash. This is observed when testing VxWorks 7.

Add a basic implementation of QSPI DMA functionality.

Signed-off-by: Xuzhou Cheng <xuzhou.cheng@windriver.com>
Signed-off-by: Bin Meng <bin.meng@windriver.com>

---

Changes in v2:
- Remove unconnected TYPE_STREAM_SINK link property
- Add a TYPE_MEMORY_REGION link property, to allow board codes to tell
  the device what its view of the world that it is doing DMA to is
- Replace cpu_physical_memory_write() with address_space_write()

 include/hw/ssi/xilinx_spips.h |   3 +-
 hw/ssi/xilinx_spips.c         | 207 +++++++++++++++++++++++++++++++++++++-----
 2 files changed, 186 insertions(+), 24 deletions(-)

diff --git a/include/hw/ssi/xilinx_spips.h b/include/hw/ssi/xilinx_spips.h
index 3eae734..2478839 100644
--- a/include/hw/ssi/xilinx_spips.h
+++ b/include/hw/ssi/xilinx_spips.h
@@ -99,7 +99,8 @@ typedef struct XilinxQSPIPS XilinxQSPIPS;
 struct XlnxZynqMPQSPIPS {
     XilinxQSPIPS parent_obj;
 
-    StreamSink *dma;
+    MemoryRegion *dma_mr;
+    AddressSpace *dma_as;
     int gqspi_irqline;
 
     uint32_t regs[XLNX_ZYNQMP_SPIPS_R_MAX];
diff --git a/hw/ssi/xilinx_spips.c b/hw/ssi/xilinx_spips.c
index 8a0cc22..9caca7b 100644
--- a/hw/ssi/xilinx_spips.c
+++ b/hw/ssi/xilinx_spips.c
@@ -195,12 +195,72 @@
 #define R_GQSPI_MOD_ID        (0x1fc / 4)
 #define R_GQSPI_MOD_ID_RESET  (0x10a0000)
 
-#define R_QSPIDMA_DST_CTRL         (0x80c / 4)
-#define R_QSPIDMA_DST_CTRL_RESET   (0x803ffa00)
-#define R_QSPIDMA_DST_I_MASK       (0x820 / 4)
-#define R_QSPIDMA_DST_I_MASK_RESET (0xfe)
-#define R_QSPIDMA_DST_CTRL2        (0x824 / 4)
-#define R_QSPIDMA_DST_CTRL2_RESET  (0x081bfff8)
+#define GQSPI_CNFG_MODE_EN_IO  (0)
+#define GQSPI_CNFG_MODE_EN_DMA (2)
+
+/*
+ * Ref: UG1087 (v1.7) February 8, 2019
+ * 
https://www.xilinx.com/html_docs/registers/ug1087/ug1087-zynq-ultrascale-registers.html
+ */
+REG32(GQSPI_DMA_ADDR, 0x800)
+    FIELD(GQSPI_DMA_ADDR, ADDR, 2, 30)
+REG32(GQSPI_DMA_SIZE, 0x804)
+    FIELD(GQSPI_DMA_SIZE, SIZE, 2, 27)
+REG32(GQSPI_DMA_STS, 0x808)
+    FIELD(GQSPI_DMA_STS, DONE_CNT, 13, 3)
+    FIELD(GQSPI_DMA_STS, BUSY, 0, 1)
+REG32(GQSPI_DMA_CTRL, 0x80c)
+    FIELD(GQSPI_DMA_CTRL, FIFO_LVL_HIT_THRESH, 25, 7)
+    FIELD(GQSPI_DMA_CTRL, APB_ERR_RESP, 24, 1)
+    FIELD(GQSPI_DMA_CTRL, ENDIANNESS, 23, 1)
+    FIELD(GQSPI_DMA_CTRL, AXI_BRST_TYPE, 22, 1)
+    FIELD(GQSPI_DMA_CTRL, TIMEOUT_VAL, 10, 12)
+    FIELD(GQSPI_DMA_CTRL, FIFO_THRESH, 2, 8)
+    FIELD(GQSPI_DMA_CTRL, PAUSE_STRM, 1, 1)
+    FIELD(GQSPI_DMA_CTRL, PAUSE_MEM, 0, 1)
+REG32(GQSPI_DMA_I_STS, 0x814)
+    FIELD(GQSPI_DMA_I_STS, FIFO_OVERFLOW, 7, 1)
+    FIELD(GQSPI_DMA_I_STS, INVALID_APB, 6, 1)
+    FIELD(GQSPI_DMA_I_STS, THRESH_HIT, 5, 1)
+    FIELD(GQSPI_DMA_I_STS, TIMEOUT_MEM, 4, 1)
+    FIELD(GQSPI_DMA_I_STS, TIMEOUT_STRM, 3, 1)
+    FIELD(GQSPI_DMA_I_STS, AXI_BRESP_ERR, 2, 1)
+    FIELD(GQSPI_DMA_I_STS, DONE, 1, 1)
+REG32(GQSPI_DMA_I_EN, 0x818)
+    FIELD(GQSPI_DMA_I_EN, FIFO_OVERFLOW, 7, 1)
+    FIELD(GQSPI_DMA_I_EN, INVALID_APB, 6, 1)
+    FIELD(GQSPI_DMA_I_EN, THRESH_HIT, 5, 1)
+    FIELD(GQSPI_DMA_I_EN, TIMEOUT_MEM, 4, 1)
+    FIELD(GQSPI_DMA_I_EN, TIMEOUT_STRM, 3, 1)
+    FIELD(GQSPI_DMA_I_EN, AXI_BRESP_ERR, 2, 1)
+    FIELD(GQSPI_DMA_I_EN, DONE, 1, 1)
+REG32(GQSPI_DMA_I_DIS, 0x81c)
+    FIELD(GQSPI_DMA_I_DIS, FIFO_OVERFLOW, 7, 1)
+    FIELD(GQSPI_DMA_I_DIS, INVALID_APB, 6, 1)
+    FIELD(GQSPI_DMA_I_DIS, THRESH_HIT, 5, 1)
+    FIELD(GQSPI_DMA_I_DIS, TIMEOUT_MEM, 4, 1)
+    FIELD(GQSPI_DMA_I_DIS, TIMEOUT_STRM, 3, 1)
+    FIELD(GQSPI_DMA_I_DIS, AXI_BRESP_ERR, 2, 1)
+    FIELD(GQSPI_DMA_I_DIS, DONE, 1, 1)
+REG32(GQSPI_DMA_I_MASK, 0x820)
+    FIELD(GQSPI_DMA_I_MASK, FIFO_OVERFLOW, 7, 1)
+    FIELD(GQSPI_DMA_I_MASK, INVALID_APB, 6, 1)
+    FIELD(GQSPI_DMA_I_MASK, THRESH_HIT, 5, 1)
+    FIELD(GQSPI_DMA_I_MASK, TIMEOUT_MEM, 4, 1)
+    FIELD(GQSPI_DMA_I_MASK, TIMEOUT_STRM, 3, 1)
+    FIELD(GQSPI_DMA_I_MASK, AXI_BRESP_ERR, 2, 1)
+    FIELD(GQSPI_DMA_I_MASK, DONE, 1, 1)
+REG32(GQSPI_DMA_CTRL2, 0x824)
+    FIELD(GQSPI_DMA_CTRL2, ARCACHE, 24, 3)
+    FIELD(GQSPI_DMA_CTRL2, TIMEOUT_EN, 22, 1)
+    FIELD(GQSPI_DMA_CTRL2, TIMEOUT_PRE, 4, 12)
+    FIELD(GQSPI_DMA_CTRL2, MAX_OUTS_CMDS, 0, 4)
+REG32(GQSPI_DMA_ADDR_MSB, 0x828)
+    FIELD(GQSPI_DMA_ADDR_MSB, ADDR_MSB, 0, 12)
+
+#define R_GQSPI_DMA_CTRL_RESET    (0x803ffa00)
+#define R_GQSPI_DMA_INT_MASK      (0xfe)
+#define R_GQSPI_DMA_CTRL2_RESET   (0x081bfff8)
 
 /* size of TXRX FIFOs */
 #define RXFF_A          (128)
@@ -341,6 +401,7 @@ static void xilinx_spips_update_ixr(XilinxSPIPS *s)
 static void xlnx_zynqmp_qspips_update_ixr(XlnxZynqMPQSPIPS *s)
 {
     uint32_t gqspi_int;
+    uint32_t mode;
     int new_irqline;
 
     s->regs[R_GQSPI_ISR] &= ~IXR_SELF_CLEAR;
@@ -359,13 +420,20 @@ static void 
xlnx_zynqmp_qspips_update_ixr(XlnxZynqMPQSPIPS *s)
                                     IXR_TX_FIFO_NOT_FULL : 0);
 
     /* GQSPI Interrupt Trigger Status */
-    gqspi_int = (~s->regs[R_GQSPI_IMR]) & s->regs[R_GQSPI_ISR] & 
GQSPI_IXR_MASK;
-    new_irqline = !!(gqspi_int & IXR_ALL);
-
-    /* drive external interrupt pin */
-    if (new_irqline != s->gqspi_irqline) {
-        s->gqspi_irqline = new_irqline;
-        qemu_set_irq(XILINX_SPIPS(s)->irq, s->gqspi_irqline);
+    mode = ARRAY_FIELD_EX32(s->regs, GQSPI_CNFG, MODE_EN);
+    if (mode == GQSPI_CNFG_MODE_EN_IO) {
+        gqspi_int = (~s->regs[R_GQSPI_IMR]) & s->regs[R_GQSPI_ISR] \
+                                            & GQSPI_IXR_MASK;
+        new_irqline = !!(gqspi_int & IXR_ALL);
+
+        /* drive external interrupt pin */
+        if (new_irqline != s->gqspi_irqline) {
+            s->gqspi_irqline = new_irqline;
+            qemu_set_irq(XILINX_SPIPS(s)->irq, s->gqspi_irqline);
+        }
+    } else if (mode == GQSPI_CNFG_MODE_EN_DMA) {
+        new_irqline = s->regs[R_GQSPI_DMA_I_STS] & 
~s->regs[R_GQSPI_DMA_I_MASK];
+        qemu_set_irq(XILINX_SPIPS(s)->irq, !!new_irqline);
     }
 }
 
@@ -417,9 +485,9 @@ static void xlnx_zynqmp_qspips_reset(DeviceState *d)
     s->regs[R_GQSPI_GPIO] = 1;
     s->regs[R_GQSPI_LPBK_DLY_ADJ] = R_GQSPI_LPBK_DLY_ADJ_RESET;
     s->regs[R_GQSPI_MOD_ID] = R_GQSPI_MOD_ID_RESET;
-    s->regs[R_QSPIDMA_DST_CTRL] = R_QSPIDMA_DST_CTRL_RESET;
-    s->regs[R_QSPIDMA_DST_I_MASK] = R_QSPIDMA_DST_I_MASK_RESET;
-    s->regs[R_QSPIDMA_DST_CTRL2] = R_QSPIDMA_DST_CTRL2_RESET;
+    s->regs[R_GQSPI_DMA_CTRL] = R_GQSPI_DMA_CTRL_RESET;
+    s->regs[R_GQSPI_DMA_I_MASK] = R_GQSPI_DMA_INT_MASK;
+    s->regs[R_GQSPI_DMA_CTRL2] = R_GQSPI_DMA_CTRL2_RESET;
     s->man_start_com_g = false;
     s->gqspi_irqline = 0;
     xlnx_zynqmp_qspips_update_ixr(s);
@@ -843,6 +911,66 @@ static const void *pop_buf(Fifo8 *fifo, uint32_t max, 
uint32_t *num)
     return ret;
 }
 
+static void xlnx_zynqmp_gspips_dma_done(XlnxZynqMPQSPIPS *s)
+{
+    int cnt;
+
+    s->regs[R_GQSPI_DMA_STS] &= ~R_GQSPI_DMA_STS_BUSY_MASK;
+    s->regs[R_GQSPI_DMA_I_STS] |= R_GQSPI_DMA_I_STS_DONE_MASK;
+
+    cnt = ARRAY_FIELD_EX32(s->regs, GQSPI_DMA_STS, DONE_CNT) + 1;
+    ARRAY_FIELD_DP32(s->regs, GQSPI_DMA_STS, DONE_CNT, cnt);
+
+}
+
+static uint32_t xlnx_zynqmp_gspips_dma_advance(XlnxZynqMPQSPIPS *s,
+                                               uint32_t len, hwaddr dst)
+{
+    uint32_t size = s->regs[R_GQSPI_DMA_SIZE];
+
+    size -= len;
+    size &= R_GQSPI_DMA_SIZE_SIZE_MASK;
+    dst += len;
+
+    s->regs[R_GQSPI_DMA_SIZE] = size;
+    s->regs[R_GQSPI_DMA_ADDR] = (uint32_t) dst;
+    s->regs[R_GQSPI_DMA_ADDR_MSB] = dst >> 32;
+
+    return size;
+}
+
+static size_t xlnx_zynqmp_gspips_dma_push(XlnxZynqMPQSPIPS *s,
+                                          uint8_t *buf, size_t len, bool eop)
+{
+    hwaddr dst = (hwaddr)s->regs[R_GQSPI_DMA_ADDR_MSB] << 32
+                 | s->regs[R_GQSPI_DMA_ADDR];
+    uint32_t size = s->regs[R_GQSPI_DMA_SIZE];
+    uint32_t mlen = MIN(size, len) & (~3); /* Size is word aligned */
+
+    if (size == 0 || len <= 0) {
+        return 0;
+    }
+
+    if (address_space_write(s->dma_as, dst, MEMTXATTRS_UNSPECIFIED, buf, mlen)
+        != MEMTX_OK) {
+        return 0;
+    }
+
+    size = xlnx_zynqmp_gspips_dma_advance(s, mlen, dst);
+
+    if (size == 0) {
+        xlnx_zynqmp_gspips_dma_done(s);
+        xlnx_zynqmp_qspips_update_ixr(s);
+    }
+
+   return mlen;
+}
+
+static bool xlnx_zynqmp_gspips_dma_can_push(XlnxZynqMPQSPIPS *s)
+{
+    return s->regs[R_GQSPI_DMA_SIZE] ? true : false;
+}
+
 static void xlnx_zynqmp_qspips_notify(void *opaque)
 {
     XlnxZynqMPQSPIPS *rq = XLNX_ZYNQMP_QSPIPS(opaque);
@@ -850,7 +978,8 @@ static void xlnx_zynqmp_qspips_notify(void *opaque)
     Fifo8 *recv_fifo;
 
     if (ARRAY_FIELD_EX32(rq->regs, GQSPI_SELECT, GENERIC_QSPI_EN)) {
-        if (!(ARRAY_FIELD_EX32(rq->regs, GQSPI_CNFG, MODE_EN) == 2)) {
+        if (ARRAY_FIELD_EX32(rq->regs, GQSPI_CNFG, MODE_EN)
+            != GQSPI_CNFG_MODE_EN_DMA) {
             return;
         }
         recv_fifo = &rq->rx_fifo_g;
@@ -861,7 +990,7 @@ static void xlnx_zynqmp_qspips_notify(void *opaque)
         recv_fifo = &s->rx_fifo;
     }
     while (recv_fifo->num >= 4
-           && stream_can_push(rq->dma, xlnx_zynqmp_qspips_notify, rq))
+           && xlnx_zynqmp_gspips_dma_can_push(rq))
     {
         size_t ret;
         uint32_t num;
@@ -874,7 +1003,7 @@ static void xlnx_zynqmp_qspips_notify(void *opaque)
 
         memcpy(rq->dma_buf, rxd, num);
 
-        ret = stream_push(rq->dma, rq->dma_buf, num, false);
+        ret = xlnx_zynqmp_gspips_dma_push(rq, rq->dma_buf, num, false);
         assert(ret == num);
         xlnx_zynqmp_qspips_check_flush(rq);
     }
@@ -1127,6 +1256,31 @@ static void xlnx_zynqmp_qspips_write(void *opaque, 
hwaddr addr,
         case R_GQSPI_GF_SNAPSHOT:
         case R_GQSPI_MOD_ID:
             break;
+        case R_GQSPI_DMA_ADDR:
+            s->regs[R_GQSPI_DMA_ADDR] = value & R_GQSPI_DMA_ADDR_ADDR_MASK;
+            break;
+        case R_GQSPI_DMA_SIZE:
+            s->regs[R_GQSPI_DMA_SIZE] = value & R_GQSPI_DMA_SIZE_SIZE_MASK;
+            break;
+        case R_GQSPI_DMA_STS:
+            s->regs[R_GQSPI_DMA_STS] &= ~(value &
+                                          R_GQSPI_DMA_STS_DONE_CNT_MASK);
+            break;
+        case R_GQSPI_DMA_I_EN:
+            s->regs[R_GQSPI_DMA_I_EN]    = value & R_GQSPI_DMA_INT_MASK;
+            s->regs[R_GQSPI_DMA_I_MASK] &= ~s->regs[R_GQSPI_DMA_I_EN];
+            s->regs[R_GQSPI_DMA_I_DIS]  &= ~s->regs[R_GQSPI_DMA_I_EN];
+            break;
+        case R_GQSPI_DMA_I_DIS:
+            s->regs[R_GQSPI_DMA_I_DIS]  |= value & R_GQSPI_DMA_INT_MASK;
+            s->regs[R_GQSPI_DMA_I_MASK] |= s->regs[R_GQSPI_DMA_I_DIS];
+            s->regs[R_GQSPI_DMA_I_EN]   &= ~s->regs[R_GQSPI_DMA_I_DIS];
+            s->regs[R_GQSPI_DMA_STS] &= 0;
+            break;
+        case R_GQSPI_DMA_ADDR_MSB:
+            s->regs[R_GQSPI_DMA_ADDR_MSB] = value &
+                                            R_GQSPI_DMA_ADDR_MSB_ADDR_MSB_MASK;
+            break;
         default:
             s->regs[reg] = value;
             break;
@@ -1353,15 +1507,22 @@ static void xlnx_zynqmp_qspips_realize(DeviceState 
*dev, Error **errp)
     fifo8_create(&s->rx_fifo_g, xsc->rx_fifo_size);
     fifo8_create(&s->tx_fifo_g, xsc->tx_fifo_size);
     fifo32_create(&s->fifo_g, 32);
+
+    if (s->dma_mr) {
+        s->dma_as = g_malloc0(sizeof(AddressSpace));
+        address_space_init(s->dma_as, s->dma_mr, NULL);
+    } else {
+        s->dma_as = &address_space_memory;
+    }
 }
 
 static void xlnx_zynqmp_qspips_init(Object *obj)
 {
-    XlnxZynqMPQSPIPS *rq = XLNX_ZYNQMP_QSPIPS(obj);
+    XlnxZynqMPQSPIPS *s = XLNX_ZYNQMP_QSPIPS(obj);
 
-    object_property_add_link(obj, "stream-connected-dma", TYPE_STREAM_SINK,
-                             (Object **)&rq->dma,
-                             object_property_allow_set_link,
+    object_property_add_link(obj, "xlnx_zynqmp_qspips_dma", TYPE_MEMORY_REGION,
+                             (Object **)&s->dma_mr,
+                             qdev_prop_allow_set_link_before_realize,
                              OBJ_PROP_LINK_STRONG);
 }
 
-- 
2.7.4