SW cannot write the read-only(RO) bits of a register
and write-only(WO) bits of a register return 0 when read.
Added ro_mask[] for each register that defines which
bits in that register are RO.
When writing to a register, the RO-bits are not updated.
When reading a register, clear the WO bits and return the updated value.
Tested the registers PHB_DMA_SYNC, PHB_PCIE_HOTPLUG_STATUS, PHB_PCIE_LMR,
PHB_PCIE_DLP_TRWCTL, PHB_LEM_ERROR_AND_MASK and PHB_LEM_ERROR_OR_MASK
by writing all 1's and reading back the value.
The WO bits in these registers should read back as 0.
Signed-off-by: Saif Abrar <saif.abrar@linux.vnet.ibm.com>
---
hw/pci-host/pnv_phb4.c | 77 ++++++++++++++++++++++++++---
include/hw/pci-host/pnv_phb4.h | 7 +++
include/hw/pci-host/pnv_phb4_regs.h | 19 +++++--
tests/qtest/pnv-phb4-test.c | 60 +++++++++++++++++++++-
4 files changed, 150 insertions(+), 13 deletions(-)
diff --git a/hw/pci-host/pnv_phb4.c b/hw/pci-host/pnv_phb4.c
index b3a83837f8..a81763f34c 100644
--- a/hw/pci-host/pnv_phb4.c
+++ b/hw/pci-host/pnv_phb4.c
@@ -735,6 +735,10 @@ static void pnv_phb4_reg_write(void *opaque, hwaddr off,
uint64_t val,
return;
}
+ /* Update 'val' according to the register's RO-mask */
+ val = (phb->regs[off >> 3] & phb->ro_mask[off >> 3]) |
+ (val & ~(phb->ro_mask[off >> 3]));
+
/* Record whether it changed */
changed = phb->regs[off >> 3] != val;
@@ -808,7 +812,7 @@ static void pnv_phb4_reg_write(void *opaque, hwaddr off, uint64_t val,
case PHB_TCE_TAG_ENABLE:
case PHB_INT_NOTIFY_ADDR:
case PHB_INT_NOTIFY_INDEX:
- case PHB_DMARD_SYNC:
+ case PHB_DMA_SYNC:
break;
/* Noise on anything else */
@@ -846,7 +850,7 @@ static uint64_t pnv_phb4_reg_read(void *opaque, hwaddr off,
unsigned size)
case PHB_VERSION:
return PNV_PHB4_PEC_GET_CLASS(phb->pec)->version;
- /* Read-only */
+ /* Read-only */
case PHB_PHB4_GEN_CAP:
return 0xe4b8000000000000ull;
case PHB_PHB4_TCE_CAP:
@@ -856,18 +860,49 @@ static uint64_t pnv_phb4_reg_read(void *opaque, hwaddr
off, unsigned size)
case PHB_PHB4_EEH_CAP:
return phb->big_phb ? 0x2000000000000000ull : 0x1000000000000000ull;
+ /* Write-only, read will return zeros */
+ case PHB_LEM_ERROR_AND_MASK:
+ case PHB_LEM_ERROR_OR_MASK:
+ return 0;
+ case PHB_PCIE_DLP_TRWCTL:
+ val &= ~PHB_PCIE_DLP_TRWCTL_WREN;
+ return val;
/* IODA table accesses */
case PHB_IODA_DATA0:
return pnv_phb4_ioda_read(phb);
+ /*
+ * DMA sync: make it look like it's complete,
+ * clear write-only read/write start sync bits.
+ */
+ case PHB_DMA_SYNC:
+ val = PHB_DMA_SYNC_RD_COMPLETE |
+ ~(PHB_DMA_SYNC_RD_START | PHB_DMA_SYNC_WR_START);
+ return val;
+
+ /*
+ * PCI-E Stack registers
+ */
+ case PHB_PCIE_SCR:
+ val |= PHB_PCIE_SCR_PLW_X16; /* RO bit */
+ break;
+
/* Link training always appears trained */
case PHB_PCIE_DLP_TRAIN_CTL:
/* TODO: Do something sensible with speed ? */
- return PHB_PCIE_DLP_INBAND_PRESENCE | PHB_PCIE_DLP_TL_LINKACT;
+ val |= PHB_PCIE_DLP_INBAND_PRESENCE | PHB_PCIE_DLP_TL_LINKACT;
+ return val;
+
+ case PHB_PCIE_HOTPLUG_STATUS:
+ /* Clear write-only bit */
+ val &= ~PHB_PCIE_HPSTAT_RESAMPLE;
+ return val;
- /* DMA read sync: make it look like it's complete */
- case PHB_DMARD_SYNC:
- return PHB_DMARD_SYNC_COMPLETE;
+ /* Link Management Register */
+ case PHB_PCIE_LMR:
+ /* These write-only bits always read as 0 */
+ val &= ~(PHB_PCIE_LMR_CHANGELW | PHB_PCIE_LMR_RETRAINLINK);
+ return val;
/* Silent simple reads */
case PHB_LSI_SOURCE_ID:
@@ -1712,6 +1747,33 @@ static PCIIOMMUOps pnv_phb4_iommu_ops = {
.get_address_space = pnv_phb4_dma_iommu,
};
+static void pnv_phb4_ro_mask_init(PnvPHB4 *phb)
+{
+ /* Clear RO-mask to make all regs as R/W by default */
+ memset(phb->ro_mask, 0x0, PNV_PHB4_NUM_REGS * sizeof(uint64_t));
+
+ /*
+ * Set register specific RO-masks
+ */
+
+ /* PBL - Error Injection Register (0x1910) */
+ phb->ro_mask[PHB_PBL_ERR_INJECT >> 3] =
+ PPC_BITMASK(0, 23) | PPC_BITMASK(28, 35) | PPC_BIT(38) | PPC_BIT(46) |
+ PPC_BITMASK(49, 51) | PPC_BITMASK(55, 63);
+
+ /* Reserved bits[60:63] */
+ phb->ro_mask[PHB_TXE_ERR_LEM_ENABLE >> 3] =
+ phb->ro_mask[PHB_TXE_ERR_AIB_FENCE_ENABLE >> 3] = PPC_BITMASK(60, 63);
+ /* Reserved bits[36:63] */
+ phb->ro_mask[PHB_RXE_TCE_ERR_LEM_ENABLE >> 3] =
+ phb->ro_mask[PHB_RXE_TCE_ERR_AIB_FENCE_ENABLE >> 3] = PPC_BITMASK(36, 63);
+ /* Reserved bits[40:63] */
+ phb->ro_mask[PHB_ERR_LEM_ENABLE >> 3] =
+ phb->ro_mask[PHB_ERR_AIB_FENCE_ENABLE >> 3] = PPC_BITMASK(40, 63);
+ /* TODO: Add more RO-masks as regs are implemented in the model */
+}
+
static void pnv_phb4_err_reg_reset(PnvPHB4 *phb)
{
STICKY_RST(PHB_ERR_STATUS, 0, PPC_BITMASK(0, 33));
@@ -1782,6 +1844,9 @@ static void pnv_phb4_instance_init(Object *obj)
/* XIVE interrupt source object */
object_initialize_child(obj, "source", &phb->xsrc, TYPE_XIVE_SOURCE);
+
+ /* Initialize RO-mask of registers */
+ pnv_phb4_ro_mask_init(phb);
}
void pnv_phb4_bus_init(DeviceState *dev, PnvPHB4 *phb)
diff --git a/include/hw/pci-host/pnv_phb4.h b/include/hw/pci-host/pnv_phb4.h
index 3212e68160..91e81eee0e 100644
--- a/include/hw/pci-host/pnv_phb4.h
+++ b/include/hw/pci-host/pnv_phb4.h
@@ -94,6 +94,13 @@ struct PnvPHB4 {
uint64_t regs[PNV_PHB4_NUM_REGS];
MemoryRegion mr_regs;
+ /*
+ * Read-only bitmask for registers
+ * Bit value: 1 => RO bit
+ * 0 => RW bit
+ */
+ uint64_t ro_mask[PNV_PHB4_NUM_REGS];> +
/* Extra SCOM-only register */
uint64_t scom_hv_ind_addr_reg;
diff --git a/include/hw/pci-host/pnv_phb4_regs.h b/include/hw/pci-host/pnv_phb4_regs.h
index df5e86d29a..391d6a89ea 100644
--- a/include/hw/pci-host/pnv_phb4_regs.h
+++ b/include/hw/pci-host/pnv_phb4_regs.h
@@ -180,9 +180,11 @@
#define PHB_M64_AOMASK 0x1d0
#define PHB_M64_UPPER_BITS 0x1f0
#define PHB_NXLATE_PREFIX 0x1f8
-#define PHB_DMARD_SYNC 0x200
-#define PHB_DMARD_SYNC_START PPC_BIT(0)
-#define PHB_DMARD_SYNC_COMPLETE PPC_BIT(1)
+#define PHB_DMA_SYNC 0x200
+#define PHB_DMA_SYNC_RD_START PPC_BIT(0)
+#define PHB_DMA_SYNC_RD_COMPLETE PPC_BIT(1)
+#define PHB_DMA_SYNC_WR_START PPC_BIT(2)
+#define PHB_DMA_SYNC_WR_COMPLETE PPC_BIT(3)
#define PHB_RTC_INVALIDATE 0x208
#define PHB_RTC_INVALIDATE_ALL PPC_BIT(0)
#define PHB_RTC_INVALIDATE_RID PPC_BITMASK(16, 31)
@@ -395,8 +397,8 @@
#define PHB_PCIE_SCR 0x1A00
#define PHB_PCIE_SCR_SLOT_CAP PPC_BIT(15)
#define PHB_PCIE_SCR_MAXLINKSPEED PPC_BITMASK(32, 35)
+#define PHB_PCIE_SCR_PLW_X16 PPC_BIT(41) /* x16 */
#define PHB_PCIE_BNR 0x1A08
-
#define PHB_PCIE_CRESET 0x1A10
#define PHB_PCIE_CRESET_CFG_CORE PPC_BIT(0)
#define PHB_PCIE_CRESET_TLDLP PPC_BIT(1)
@@ -405,7 +407,14 @@
#define PHB_PCIE_CRESET_PIPE_N PPC_BIT(4)
#define PHB_PCIE_CRESET_REFCLK_N PPC_BIT(8)
#define PHB_PCIE_HOTPLUG_STATUS 0x1A20
+#define PHB_PCIE_HPSTAT_SIMDIAG PPC_BIT(3)
+#define PHB_PCIE_HPSTAT_RESAMPLE PPC_BIT(9)
#define PHB_PCIE_HPSTAT_PRESENCE PPC_BIT(10)
+#define PHB_PCIE_HPSTAT_LINKACTIVE PPC_BIT(12)
+#define PHB_PCIE_LMR 0x1A30
+#define PHB_PCIE_LMR_CHANGELW PPC_BIT(0)
+#define PHB_PCIE_LMR_RETRAINLINK PPC_BIT(1)
+#define PHB_PCIE_LMR_LINKACTIVE PPC_BIT(8)
#define PHB_PCIE_DLP_TRAIN_CTL 0x1A40
#define PHB_PCIE_DLP_LINK_WIDTH PPC_BITMASK(30, 35)
@@ -433,7 +442,7 @@
#define PHB_PCIE_DLP_TRWCTL 0x1A80
#define PHB_PCIE_DLP_TRWCTL_EN PPC_BIT(0)
-
+#define PHB_PCIE_DLP_TRWCTL_WREN PPC_BIT(1)
#define PHB_PCIE_DLP_ERRLOG1 0x1AA0
#define PHB_PCIE_DLP_ERRLOG2 0x1AA8
#define PHB_PCIE_DLP_ERR_STATUS 0x1AB0
diff --git a/tests/qtest/pnv-phb4-test.c b/tests/qtest/pnv-phb4-test.c
index 708df3867c..0c8e58dd5f 100644
--- a/tests/qtest/pnv-phb4-test.c
+++ b/tests/qtest/pnv-phb4-test.c
@@ -75,7 +75,8 @@ static void phb4_sticky_rst_test(QTestState *qts)
* Sticky reset test of PHB_PBL_ERR_STATUS.
*
* Write all 1's to reg PHB_PBL_ERR_INJECT.
- * Updated value will be copied to reg PHB_PBL_ERR_STATUS.
+ * RO-only bits will not be written and
+ * updated value will be copied to reg PHB_PBL_ERR_STATUS.
*
* Reset PBL core by setting PHB_PCIE_CRESET_PBL in reg PHB_PCIE_CRESET.
* Verify the sticky bits are still set.
@@ -83,7 +84,59 @@ static void phb4_sticky_rst_test(QTestState *qts)
pnv_phb4_xscom_write(qts, PHB_PBL_ERR_INJECT, PPC_BITMASK(0, 63));
pnv_phb4_xscom_write(qts, PHB_PCIE_CRESET, PHB_PCIE_CRESET_PBL); /*Reset*/
val = pnv_phb4_xscom_read(qts, PHB_PBL_ERR_STATUS);
- g_assert_cmpuint(val, ==, (PPC_BITMASK(0, 9) | PPC_BITMASK(12, 63)));
+ g_assert_cmpuint(val, ==, 0xF00DFD8E00);
+}
+
+/* Check that write-only bits/regs return 0 when read */
+static void phb4_writeonly_read_test(QTestState *qts)
+{
+ uint64_t val;
+
+ /*
+ * Set all bits of PHB_DMA_SYNC,
+ * bits 0 and 2 are write-only and should be read as 0.
+ */
+ pnv_phb4_xscom_write(qts, PHB_DMA_SYNC, PPC_BITMASK(0, 63));
+ val = pnv_phb4_xscom_read(qts, PHB_DMA_SYNC);
+ g_assert_cmpuint(val & PPC_BIT(0), ==, 0x0);
+ g_assert_cmpuint(val & PPC_BIT(2), ==, 0x0);
+
+ /*
+ * Set all bits of PHB_PCIE_HOTPLUG_STATUS,
+ * bit 9 is write-only and should be read as 0.
+ */
+ pnv_phb4_xscom_write(qts, PHB_PCIE_HOTPLUG_STATUS, PPC_BITMASK(0, 63));
+ val = pnv_phb4_xscom_read(qts, PHB_PCIE_HOTPLUG_STATUS);
+ g_assert_cmpuint(val & PPC_BIT(9), ==, 0x0);
+
+ /*
+ * Set all bits of PHB_PCIE_LMR,
+ * bits 0 and 1 are write-only and should be read as 0.
+ */
+ pnv_phb4_xscom_write(qts, PHB_PCIE_LMR, PPC_BITMASK(0, 63));
+ val = pnv_phb4_xscom_read(qts, PHB_PCIE_LMR);
+ g_assert_cmpuint(val & PPC_BIT(0), ==, 0x0);
+ g_assert_cmpuint(val & PPC_BIT(1), ==, 0x0);
+
+ /*
+ * Set all bits of PHB_PCIE_DLP_TRWCTL,
+ * write-only bit-1 should be read as 0.
+ */
+ pnv_phb4_xscom_write(qts, PHB_PCIE_DLP_TRWCTL, PPC_BITMASK(0, 63));
+ val = pnv_phb4_xscom_read(qts, PHB_PCIE_DLP_TRWCTL);
+ g_assert_cmpuint(val & PPC_BIT(1), ==, 0x0);
+
+ /*
+ * Set all bits of PHB_LEM_ERROR_AND_MASK, PHB_LEM_ERROR_OR_MASK,
+ * both regs are write-only and should be read as 0.
+ */
+ pnv_phb4_xscom_write(qts, PHB_LEM_ERROR_AND_MASK, PPC_BITMASK(0, 63));
+ val = pnv_phb4_xscom_read(qts, PHB_LEM_ERROR_AND_MASK);
+ g_assert_cmpuint(val, ==, 0x0);
+
+ pnv_phb4_xscom_write(qts, PHB_LEM_ERROR_OR_MASK, PPC_BITMASK(0, 63));
+ val = pnv_phb4_xscom_read(qts, PHB_LEM_ERROR_OR_MASK);
+ g_assert_cmpuint(val, ==, 0x0);
}
static void test_phb4(void)
@@ -101,6 +154,9 @@ static void test_phb4(void)
/* Check sticky reset of a register */
phb4_sticky_rst_test(qts);
+ /* Check write-only logic */
+ phb4_writeonly_read_test(qts);
+
qtest_quit(qts);
}