[PATCH 11/15] NTB: NTB-RP support

From: Jon Mason
Date: Fri Aug 02 2013 - 13:38:41 EST

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Add support for Non-Transparent Bridge connected to a PCI-E Root Port on
the remote system (also known as NTB-RP mode). This allows for a NTB
enabled system to be connected to a non-NTB enabled system/slot.

Modifications to the registers and BARs/MWs on the Secondary side by the
remote system are reflected into registers on the Primary side for the
local system. Similarly, modifications of registers and BARs/MWs on
Primary side by the local system are reflected into registers on the
Secondary side for the Remote System. This allows communication between
the 2 sides via these registers and BARs/MWs.

Note: there is not a fix for the Xeon Errata (that was already worked
around in NTB-B2B mode) for NTB-RP mode. Due to this limitation, NTB-RP
will not work on the Secondary side with the Xeon Errata workaround
enabled. To get around this, disable the workaround via the
xeon_errata_workaround=0 modparm. However, this can cause the hang
described in the errata.

Signed-off-by: Jon Mason <jon.mason@xxxxxxxxx>
---
drivers/ntb/ntb_hw.c | 239 +++++++++++++++++++++++++++++-------------------
drivers/ntb/ntb_regs.h | 5 +-
2 files changed, 150 insertions(+), 94 deletions(-)

diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
index e7cbb44..371b65e 100644
--- a/drivers/ntb/ntb_hw.c
+++ b/drivers/ntb/ntb_hw.c
@@ -69,7 +69,7 @@ module_param(xeon_errata_workaround, bool, 0644);
MODULE_PARM_DESC(xeon_errata_workaround, "Workaround for the Xeon Errata");

enum {
- NTB_CONN_CLASSIC = 0,
+ NTB_CONN_TRANSPARENT = 0,
NTB_CONN_B2B,
NTB_CONN_RP,
};
@@ -509,7 +509,8 @@ static void ntb_link_event(struct ntb_device *ndev, int link_state)
ndev->link_status = NTB_LINK_UP;
event = NTB_EVENT_HW_LINK_UP;

- if (ndev->hw_type == BWD_HW)
+ if (ndev->hw_type == BWD_HW ||
+ ndev->conn_type == NTB_CONN_TRANSPARENT)
status = readw(ndev->reg_ofs.lnk_stat);
else {
int rc = pci_read_config_word(ndev->pdev,
@@ -649,109 +650,161 @@ static int ntb_xeon_setup(struct ntb_device *ndev)
if (rc)
return rc;

- switch (val & SNB_PPD_CONN_TYPE) {
- case NTB_CONN_B2B:
- ndev->conn_type = NTB_CONN_B2B;
- break;
- case NTB_CONN_CLASSIC:
- case NTB_CONN_RP:
- default:
- dev_err(&ndev->pdev->dev, "Only B2B supported at this time\n");
- return -EINVAL;
- }
-
if (val & SNB_PPD_DEV_TYPE)
ndev->dev_type = NTB_DEV_USD;
else
ndev->dev_type = NTB_DEV_DSD;

- ndev->reg_ofs.ldb = ndev->reg_base + SNB_PDOORBELL_OFFSET;
- ndev->reg_ofs.ldb_mask = ndev->reg_base + SNB_PDBMSK_OFFSET;
- ndev->reg_ofs.bar2_xlat = ndev->reg_base + SNB_SBAR2XLAT_OFFSET;
- ndev->reg_ofs.bar4_xlat = ndev->reg_base + SNB_SBAR4XLAT_OFFSET;
- ndev->reg_ofs.lnk_cntl = ndev->reg_base + SNB_NTBCNTL_OFFSET;
- ndev->reg_ofs.lnk_stat = ndev->reg_base + SNB_LINK_STATUS_OFFSET;
- ndev->reg_ofs.spad_read = ndev->reg_base + SNB_SPAD_OFFSET;
- ndev->reg_ofs.spci_cmd = ndev->reg_base + SNB_PCICMD_OFFSET;
-
- /* There is a Xeon hardware errata related to writes to
- * SDOORBELL or B2BDOORBELL in conjunction with inbound access
- * to NTB MMIO Space, which may hang the system. To workaround
- * this use the second memory window to access the interrupt and
- * scratch pad registers on the remote system.
- */
- if (xeon_errata_workaround) {
- if (!ndev->mw[1].bar_sz)
- return -EINVAL;
-
- ndev->limits.max_mw = SNB_ERRATA_MAX_MW;
- ndev->reg_ofs.spad_write = ndev->mw[1].vbase +
- SNB_SPAD_OFFSET;
- ndev->reg_ofs.rdb = ndev->mw[1].vbase +
- SNB_PDOORBELL_OFFSET;
-
- /* Set the Limit register to 4k, the minimum size, to
- * prevent an illegal access
+ switch (val & SNB_PPD_CONN_TYPE) {
+ case NTB_CONN_B2B:
+ dev_info(&ndev->pdev->dev, "Conn Type = B2B\n");
+ ndev->conn_type = NTB_CONN_B2B;
+ ndev->reg_ofs.ldb = ndev->reg_base + SNB_PDOORBELL_OFFSET;
+ ndev->reg_ofs.ldb_mask = ndev->reg_base + SNB_PDBMSK_OFFSET;
+ ndev->reg_ofs.spad_read = ndev->reg_base + SNB_SPAD_OFFSET;
+ ndev->reg_ofs.bar2_xlat = ndev->reg_base + SNB_SBAR2XLAT_OFFSET;
+ ndev->reg_ofs.bar4_xlat = ndev->reg_base + SNB_SBAR4XLAT_OFFSET;
+ ndev->limits.max_spads = SNB_MAX_B2B_SPADS;
+
+ /* There is a Xeon hardware errata related to writes to
+ * SDOORBELL or B2BDOORBELL in conjunction with inbound access
+ * to NTB MMIO Space, which may hang the system. To workaround
+ * this use the second memory window to access the interrupt and
+ * scratch pad registers on the remote system.
*/
- writeq(ndev->mw[1].bar_sz + 0x1000, ndev->reg_base +
- SNB_PBAR4LMT_OFFSET);
- } else {
- ndev->limits.max_mw = SNB_MAX_MW;
- ndev->reg_ofs.spad_write = ndev->reg_base +
- SNB_B2B_SPAD_OFFSET;
- ndev->reg_ofs.rdb = ndev->reg_base +
- SNB_B2B_DOORBELL_OFFSET;
+ if (xeon_errata_workaround) {
+ if (!ndev->mw[1].bar_sz)
+ return -EINVAL;
+
+ ndev->limits.max_mw = SNB_ERRATA_MAX_MW;
+ ndev->reg_ofs.spad_write = ndev->mw[1].vbase +
+ SNB_SPAD_OFFSET;
+ ndev->reg_ofs.rdb = ndev->mw[1].vbase +
+ SNB_PDOORBELL_OFFSET;
+
+ /* Set the Limit register to 4k, the minimum size, to
+ * prevent an illegal access
+ */
+ writeq(ndev->mw[1].bar_sz + 0x1000, ndev->reg_base +
+ SNB_PBAR4LMT_OFFSET);
+ } else {
+ ndev->limits.max_mw = SNB_MAX_MW;
+ ndev->reg_ofs.spad_write = ndev->reg_base +
+ SNB_B2B_SPAD_OFFSET;
+ ndev->reg_ofs.rdb = ndev->reg_base +
+ SNB_B2B_DOORBELL_OFFSET;
+
+ /* Disable the Limit register, just incase it is set to
+ * something silly
+ */
+ writeq(0, ndev->reg_base + SNB_PBAR4LMT_OFFSET);
+ }

- /* Disable the Limit register, just incase it is set to
- * something silly
+ /* The Xeon errata workaround requires setting SBAR Base
+ * addresses to known values, so that the PBAR XLAT can be
+ * pointed at SBAR0 of the remote system.
*/
- writeq(0, ndev->reg_base + SNB_PBAR4LMT_OFFSET);
- }
+ if (ndev->dev_type == NTB_DEV_USD) {
+ writeq(SNB_MBAR23_DSD_ADDR, ndev->reg_base +
+ SNB_PBAR2XLAT_OFFSET);
+ if (xeon_errata_workaround)
+ writeq(SNB_MBAR01_DSD_ADDR, ndev->reg_base +
+ SNB_PBAR4XLAT_OFFSET);
+ else {
+ writeq(SNB_MBAR45_DSD_ADDR, ndev->reg_base +
+ SNB_PBAR4XLAT_OFFSET);
+ writeq(SNB_MBAR01_DSD_ADDR, ndev->reg_base +
+ SNB_B2B_XLAT_OFFSET);
+ }

- /* The Xeon errata workaround requires setting SBAR Base
- * addresses to known values, so that the PBAR XLAT can be
- * pointed at SBAR0 of the remote system.
- */
- if (ndev->dev_type == NTB_DEV_USD) {
- writeq(SNB_MBAR23_DSD_ADDR, ndev->reg_base +
- SNB_PBAR2XLAT_OFFSET);
- if (xeon_errata_workaround)
+ writeq(SNB_MBAR01_USD_ADDR, ndev->reg_base +
+ SNB_SBAR0BASE_OFFSET);
+ writeq(SNB_MBAR23_USD_ADDR, ndev->reg_base +
+ SNB_SBAR2BASE_OFFSET);
+ writeq(SNB_MBAR45_USD_ADDR, ndev->reg_base +
+ SNB_SBAR4BASE_OFFSET);
+ } else {
+ writeq(SNB_MBAR23_USD_ADDR, ndev->reg_base +
+ SNB_PBAR2XLAT_OFFSET);
+ if (xeon_errata_workaround)
+ writeq(SNB_MBAR01_USD_ADDR, ndev->reg_base +
+ SNB_PBAR4XLAT_OFFSET);
+ else {
+ writeq(SNB_MBAR45_USD_ADDR, ndev->reg_base +
+ SNB_PBAR4XLAT_OFFSET);
+ writeq(SNB_MBAR01_USD_ADDR, ndev->reg_base +
+ SNB_B2B_XLAT_OFFSET);
+ }
writeq(SNB_MBAR01_DSD_ADDR, ndev->reg_base +
- SNB_PBAR4XLAT_OFFSET);
- else {
+ SNB_SBAR0BASE_OFFSET);
+ writeq(SNB_MBAR23_DSD_ADDR, ndev->reg_base +
+ SNB_SBAR2BASE_OFFSET);
writeq(SNB_MBAR45_DSD_ADDR, ndev->reg_base +
- SNB_PBAR4XLAT_OFFSET);
- writeq(SNB_MBAR01_DSD_ADDR, ndev->reg_base +
- SNB_B2B_XLAT_OFFSET);
+ SNB_SBAR4BASE_OFFSET);
}
+ break;
+ case NTB_CONN_RP:
+ dev_info(&ndev->pdev->dev, "Conn Type = RP\n");
+ ndev->conn_type = NTB_CONN_RP;

- writeq(SNB_MBAR01_USD_ADDR, ndev->reg_base +
- SNB_SBAR0BASE_OFFSET);
- writeq(SNB_MBAR23_USD_ADDR, ndev->reg_base +
- SNB_SBAR2BASE_OFFSET);
- writeq(SNB_MBAR45_USD_ADDR, ndev->reg_base +
- SNB_SBAR4BASE_OFFSET);
- } else {
- writeq(SNB_MBAR23_USD_ADDR, ndev->reg_base +
- SNB_PBAR2XLAT_OFFSET);
if (xeon_errata_workaround)
- writeq(SNB_MBAR01_USD_ADDR, ndev->reg_base +
- SNB_PBAR4XLAT_OFFSET);
- else {
- writeq(SNB_MBAR45_USD_ADDR, ndev->reg_base +
- SNB_PBAR4XLAT_OFFSET);
- writeq(SNB_MBAR01_USD_ADDR, ndev->reg_base +
- SNB_B2B_XLAT_OFFSET);
- }
- writeq(SNB_MBAR01_DSD_ADDR, ndev->reg_base +
- SNB_SBAR0BASE_OFFSET);
- writeq(SNB_MBAR23_DSD_ADDR, ndev->reg_base +
- SNB_SBAR2BASE_OFFSET);
- writeq(SNB_MBAR45_DSD_ADDR, ndev->reg_base +
- SNB_SBAR4BASE_OFFSET);
+ return -EINVAL;
+
+ /* Scratch pads need to have exclusive access from the primary
+ * or secondary side. Halve the num spads so that each side can
+ * have an equal amount.
+ */
+ ndev->limits.max_spads = SNB_MAX_COMPAT_SPADS / 2;
+ /* Note: The SDOORBELL is the cause of the errata. You REALLY
+ * don't want to touch it.
+ */
+ ndev->reg_ofs.rdb = ndev->reg_base + SNB_SDOORBELL_OFFSET;
+ ndev->reg_ofs.ldb = ndev->reg_base + SNB_PDOORBELL_OFFSET;
+ ndev->reg_ofs.ldb_mask = ndev->reg_base + SNB_PDBMSK_OFFSET;
+ /* Offset the start of the spads to correspond to whether it is
+ * primary or secondary
+ */
+ ndev->reg_ofs.spad_write = ndev->reg_base + SNB_SPAD_OFFSET +
+ ndev->limits.max_spads * 4;
+ ndev->reg_ofs.spad_read = ndev->reg_base + SNB_SPAD_OFFSET;
+ ndev->reg_ofs.bar2_xlat = ndev->reg_base + SNB_SBAR2XLAT_OFFSET;
+ ndev->reg_ofs.bar4_xlat = ndev->reg_base + SNB_SBAR4XLAT_OFFSET;
+ ndev->limits.max_mw = SNB_MAX_MW;
+ break;
+ case NTB_CONN_TRANSPARENT:
+ dev_info(&ndev->pdev->dev, "Conn Type = TRANSPARENT\n");
+ ndev->conn_type = NTB_CONN_TRANSPARENT;
+ /* Scratch pads need to have exclusive access from the primary
+ * or secondary side. Halve the num spads so that each side can
+ * have an equal amount.
+ */
+ ndev->limits.max_spads = SNB_MAX_COMPAT_SPADS / 2;
+ ndev->reg_ofs.rdb = ndev->reg_base + SNB_PDOORBELL_OFFSET;
+ ndev->reg_ofs.ldb = ndev->reg_base + SNB_SDOORBELL_OFFSET;
+ ndev->reg_ofs.ldb_mask = ndev->reg_base + SNB_SDBMSK_OFFSET;
+ ndev->reg_ofs.spad_write = ndev->reg_base + SNB_SPAD_OFFSET;
+ /* Offset the start of the spads to correspond to whether it is
+ * primary or secondary
+ */
+ ndev->reg_ofs.spad_read = ndev->reg_base + SNB_SPAD_OFFSET +
+ ndev->limits.max_spads * 4;
+ ndev->reg_ofs.bar2_xlat = ndev->reg_base + SNB_PBAR2XLAT_OFFSET;
+ ndev->reg_ofs.bar4_xlat = ndev->reg_base + SNB_PBAR4XLAT_OFFSET;
+
+ ndev->limits.max_mw = SNB_MAX_MW;
+ break;
+ default:
+ /* Most likely caused by the remote NTB-RP device not being
+ * configured
+ */
+ dev_err(&ndev->pdev->dev, "Unknown PPD %x\n", val);
+ return -EINVAL;
}

- ndev->limits.max_spads = SNB_MAX_B2B_SPADS;
+ ndev->reg_ofs.lnk_cntl = ndev->reg_base + SNB_NTBCNTL_OFFSET;
+ ndev->reg_ofs.lnk_stat = ndev->reg_base + SNB_SLINK_STATUS_OFFSET;
+ ndev->reg_ofs.spci_cmd = ndev->reg_base + SNB_PCICMD_OFFSET;
+
ndev->limits.max_db_bits = SNB_MAX_DB_BITS;
ndev->limits.msix_cnt = SNB_MSIX_CNT;
ndev->bits_per_vector = SNB_DB_BITS_PER_VEC;
@@ -855,8 +908,10 @@ static int ntb_device_setup(struct ntb_device *ndev)
dev_info(&ndev->pdev->dev, "Device Type = %s\n",
ndev->dev_type == NTB_DEV_USD ? "USD/DSP" : "DSD/USP");

- /* Enable Bus Master and Memory Space on the secondary side */
- writew(PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER, ndev->reg_ofs.spci_cmd);
+ if (ndev->conn_type == NTB_CONN_B2B)
+ /* Enable Bus Master and Memory Space on the secondary side */
+ writew(PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER,
+ ndev->reg_ofs.spci_cmd);

return 0;
}
@@ -1350,7 +1405,7 @@ static void ntb_pci_remove(struct pci_dev *pdev)

/* Bring NTB link down */
ntb_cntl = readl(ndev->reg_ofs.lnk_cntl);
- ntb_cntl |= NTB_LINK_DISABLE;
+ ntb_cntl |= NTB_CNTL_LINK_DISABLE;
writel(ntb_cntl, ndev->reg_ofs.lnk_cntl);

ntb_transport_free(ndev->ntb_transport);
diff --git a/drivers/ntb/ntb_regs.h b/drivers/ntb/ntb_regs.h
index 8f3f903..910d5e9 100644
--- a/drivers/ntb/ntb_regs.h
+++ b/drivers/ntb/ntb_regs.h
@@ -46,8 +46,6 @@
* Jon Mason <jon.mason@xxxxxxxxx>
*/

-#define NTB_LINK_ENABLE 0x0000
-#define NTB_LINK_DISABLE 0x0002
#define NTB_LINK_STATUS_ACTIVE 0x2000
#define NTB_LINK_SPEED_MASK 0x000f
#define NTB_LINK_WIDTH_MASK 0x03f0
@@ -65,6 +63,7 @@

#define SNB_PCICMD_OFFSET 0x0504
#define SNB_DEVCTRL_OFFSET 0x0598
+#define SNB_SLINK_STATUS_OFFSET 0x05A2
#define SNB_LINK_STATUS_OFFSET 0x01A2

#define SNB_PBAR2LMT_OFFSET 0x0000
@@ -146,6 +145,8 @@
#define BWD_LTSSMSTATEJMP_FORCEDETECT (1 << 2)
#define BWD_IBIST_ERR_OFLOW 0x7FFF7FFF

+#define NTB_CNTL_CFG_LOCK (1 << 0)
+#define NTB_CNTL_LINK_DISABLE (1 << 1)
#define NTB_CNTL_BAR23_SNOOP (1 << 2)
#define NTB_CNTL_BAR45_SNOOP (1 << 6)
#define BWD_CNTL_LINK_DOWN (1 << 16)
--
1.7.9.5

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