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NTB: NTB-RP support
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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@intel.com>
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Jon Mason committed Sep 5, 2013
1 parent 4979388 commit ed6c24e
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Showing 2 changed files with 163 additions and 104 deletions.
262 changes: 160 additions & 102 deletions drivers/ntb/ntb_hw.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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,
};
Expand Down Expand Up @@ -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,
Expand Down Expand Up @@ -649,119 +650,174 @@ 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);
/* B2B_XLAT_OFFSET is a 64bit register, but can
* only take 32bit writes
*/
writel(SNB_MBAR01_DSD_ADDR & 0xffffffff,
ndev->reg_base + SNB_B2B_XLAT_OFFSETL);
writel(SNB_MBAR01_DSD_ADDR >> 32,
ndev->reg_base + SNB_B2B_XLAT_OFFSETU);
}

/* 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);
/* B2B_XLAT_OFFSET is a 64bit register, but can
* only take 32bit writes
*/
writel(SNB_MBAR01_DSD_ADDR & 0xffffffff,
ndev->reg_base + SNB_B2B_XLAT_OFFSETL);
writel(SNB_MBAR01_USD_ADDR >> 32,
ndev->reg_base + SNB_B2B_XLAT_OFFSETU);
}
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);
/* B2B_XLAT_OFFSET is a 64bit register, but can
* only take 32bit writes
*/
writel(SNB_MBAR01_USD_ADDR & 0xffffffff,
ndev->reg_base + SNB_B2B_XLAT_OFFSETL);
writel(SNB_MBAR01_DSD_ADDR >> 32,
ndev->reg_base + SNB_B2B_XLAT_OFFSETU);
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);
/* B2B_XLAT_OFFSET is a 64bit register, but can
* only take 32bit writes
*/
writel(SNB_MBAR01_USD_ADDR & 0xffffffff,
ndev->reg_base + SNB_B2B_XLAT_OFFSETL);
writel(SNB_MBAR01_USD_ADDR >> 32,
ndev->reg_base + SNB_B2B_XLAT_OFFSETU);
if (xeon_errata_workaround) {
dev_err(&ndev->pdev->dev,
"NTB-RP disabled due to hardware errata. To disregard this warning and potentially lock-up the system, add the parameter 'xeon_errata_workaround=0'.\n");
return -EINVAL;
}
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);

/* 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;
Expand Down Expand Up @@ -865,8 +921,10 @@ 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;
}
Expand Down Expand Up @@ -1360,7 +1418,7 @@ 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);
Expand Down
5 changes: 3 additions & 2 deletions drivers/ntb/ntb_regs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -46,8 +46,6 @@
* Jon Mason <jon.mason@intel.com>
*/

#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
Expand All @@ -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
Expand Down Expand Up @@ -147,6 +146,8 @@
#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)
Expand Down

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