ntb: intel: add Intel NTB LTR vendor support for gen4 NTB

Intel NTB device has custom LTR management that is not compliant with the
PCIe standard. Add support to set LTR status triggered by link status
change.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

diff --git a/drivers/ntb/hw/intel/ntb_hw_gen1.h b/drivers/ntb/hw/intel/ntb_hw_gen1.h
index 1b75994..344249f 100644 (file)
--- a/drivers/ntb/hw/intel/ntb_hw_gen1.h
+++ b/drivers/ntb/hw/intel/ntb_hw_gen1.h
@@ -141,6 +141,7 @@
 #define NTB_HWERR_B2BDOORBELL_BIT14    BIT_ULL(2)
 #define NTB_HWERR_MSIX_VECTOR32_BAD    BIT_ULL(3)
 #define NTB_HWERR_BAR_ALIGN            BIT_ULL(4)
+#define NTB_HWERR_LTR_BAD              BIT_ULL(5)
 
 extern struct intel_b2b_addr xeon_b2b_usd_addr;
 extern struct intel_b2b_addr xeon_b2b_dsd_addr;

diff --git a/drivers/ntb/hw/intel/ntb_hw_gen4.c b/drivers/ntb/hw/intel/ntb_hw_gen4.c
index bc4541c..fede051 100644 (file)
--- a/drivers/ntb/hw/intel/ntb_hw_gen4.c
+++ b/drivers/ntb/hw/intel/ntb_hw_gen4.c
@@ -177,8 +177,10 @@ int gen4_init_dev(struct intel_ntb_dev *ndev)
 
        ndev->reg = &gen4_reg;
 
-       if (pdev_is_ICX(pdev))
+       if (pdev_is_ICX(pdev)) {
                ndev->hwerr_flags |= NTB_HWERR_BAR_ALIGN;
+               ndev->hwerr_flags |= NTB_HWERR_LTR_BAD;
+       }
 
        ppd1 = ioread32(ndev->self_mmio + GEN4_PPD1_OFFSET);
        ndev->ntb.topo = gen4_ppd_topo(ndev, ppd1);
@@ -431,6 +433,25 @@ static int intel_ntb4_link_enable(struct ntb_dev *ntb,
                dev_dbg(&ntb->pdev->dev,
                                "ignoring max_width %d\n", max_width);
 
+       if (!(ndev->hwerr_flags & NTB_HWERR_LTR_BAD)) {
+               u32 ltr;
+
+               /* Setup active snoop LTR values */
+               ltr = NTB_LTR_ACTIVE_REQMNT | NTB_LTR_ACTIVE_VAL | NTB_LTR_ACTIVE_LATSCALE;
+               /* Setup active non-snoop values */
+               ltr = (ltr << NTB_LTR_NS_SHIFT) | ltr;
+               iowrite32(ltr, ndev->self_mmio + GEN4_LTR_ACTIVE_OFFSET);
+
+               /* Setup idle snoop LTR values */
+               ltr = NTB_LTR_IDLE_VAL | NTB_LTR_IDLE_LATSCALE | NTB_LTR_IDLE_REQMNT;
+               /* Setup idle non-snoop values */
+               ltr = (ltr << NTB_LTR_NS_SHIFT) | ltr;
+               iowrite32(ltr, ndev->self_mmio + GEN4_LTR_IDLE_OFFSET);
+
+               /* setup PCIe LTR to active */
+               iowrite8(NTB_LTR_SWSEL_ACTIVE, ndev->self_mmio + GEN4_LTR_SWSEL_OFFSET);
+       }
+
        ntb_ctl = NTB_CTL_E2I_BAR23_SNOOP | NTB_CTL_I2E_BAR23_SNOOP;
        ntb_ctl |= NTB_CTL_E2I_BAR45_SNOOP | NTB_CTL_I2E_BAR45_SNOOP;
        iowrite32(ntb_ctl, ndev->self_mmio + ndev->reg->ntb_ctl);
@@ -476,6 +497,10 @@ static int intel_ntb4_link_disable(struct ntb_dev *ntb)
        lnkctl |= GEN4_LINK_CTRL_LINK_DISABLE;
        iowrite16(lnkctl, ndev->self_mmio + GEN4_LINK_CTRL_OFFSET);
 
+       /* set LTR to idle */
+       if (!(ndev->hwerr_flags & NTB_HWERR_LTR_BAD))
+               iowrite8(NTB_LTR_SWSEL_IDLE, ndev->self_mmio + GEN4_LTR_SWSEL_OFFSET);
+
        ndev->dev_up = 0;
 
        return 0;

diff --git a/drivers/ntb/hw/intel/ntb_hw_gen4.h b/drivers/ntb/hw/intel/ntb_hw_gen4.h
index a868c78..3fcd3fd 100644 (file)
--- a/drivers/ntb/hw/intel/ntb_hw_gen4.h
+++ b/drivers/ntb/hw/intel/ntb_hw_gen4.h
@@ -35,6 +35,9 @@
 #define GEN4_IM_SPAD_SEM_OFFSET                0x00c0  /* SPAD hw semaphore */
 #define GEN4_IM_SPAD_STICKY_OFFSET     0x00c4  /* sticky SPAD */
 #define GEN4_IM_DOORBELL_OFFSET                0x0100  /* 0-31 doorbells */
+#define GEN4_LTR_SWSEL_OFFSET          0x30ec
+#define GEN4_LTR_ACTIVE_OFFSET         0x30f0
+#define GEN4_LTR_IDLE_OFFSET           0x30f4
 #define GEN4_EM_SPAD_OFFSET            0x8080
 /* note, link status is now in MMIO and not config space for NTB */
 #define GEN4_LINK_CTRL_OFFSET          0xb050
@@ -80,6 +83,18 @@
 
 #define NTB_SJC_FORCEDETECT            0x000004
 
+#define NTB_LTR_SWSEL_ACTIVE           0x0
+#define NTB_LTR_SWSEL_IDLE             0x1
+
+#define NTB_LTR_NS_SHIFT               16
+#define NTB_LTR_ACTIVE_VAL             0x0000  /* 0 us */
+#define NTB_LTR_ACTIVE_LATSCALE                0x0800  /* 1us scale */
+#define NTB_LTR_ACTIVE_REQMNT          0x8000  /* snoop req enable */
+
+#define NTB_LTR_IDLE_VAL               0x0258  /* 600 us */
+#define NTB_LTR_IDLE_LATSCALE          0x0800  /* 1us scale */
+#define NTB_LTR_IDLE_REQMNT            0x8000  /* snoop req enable */
+
 ssize_t ndev_ntb4_debugfs_read(struct file *filp, char __user *ubuf,
                                      size_t count, loff_t *offp);
 int gen4_init_dev(struct intel_ntb_dev *ndev);