Intel MIC Host Driver Interrupt/SMPT support.

This patch enables the following features:
a) MSIx, MSI and legacy interrupt support.
b) System Memory Page Table(SMPT) support. SMPT enables system memory
   access from the card. On X100 devices the host can program 32 SMPT
   registers each capable of accessing 16GB of system memory
   address space from X100 devices. The registers can thereby be used
   to access a cumulative 512GB of system memory address space from
   X100 devices at any point in time.

Co-author: Sudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Caz Yokoyama <Caz.Yokoyama@intel.com>
Signed-off-by: Dasaratharaman Chandramouli <dasaratharaman.chandramouli@intel.com>
Signed-off-by: Nikhil Rao <nikhil.rao@intel.com>
Signed-off-by: Harshavardhan R Kharche <harshavardhan.r.kharche@intel.com>
Signed-off-by: Sudeep Dutt <sudeep.dutt@intel.com>
Acked-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Reviewed-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 247 insertions, 0 deletions

diff --git a/drivers/misc/mic/host/mic_x100.c b/drivers/misc/mic/host/mic_x100.c
index da481b1..b637316 100644
--- a/drivers/misc/mic/host/mic_x100.c
+++ b/drivers/misc/mic/host/mic_x100.c
@@ -24,6 +24,7 @@
 #include "../common/mic_device.h"
 #include "mic_device.h"
 #include "mic_x100.h"
+#include "mic_smpt.h"
 
 /**
  * mic_x100_write_spad - write to the scratchpad register
@@ -67,9 +68,255 @@ mic_x100_read_spad(struct mic_device *mdev, unsigned int idx)
 	return val;
 }
 
+/**
+ * mic_x100_enable_interrupts - Enable interrupts.
+ * @mdev: pointer to mic_device instance
+ */
+static void mic_x100_enable_interrupts(struct mic_device *mdev)
+{
+	u32 reg;
+	struct mic_mw *mw = &mdev->mmio;
+	u32 sice0 = MIC_X100_SBOX_BASE_ADDRESS + MIC_X100_SBOX_SICE0;
+	u32 siac0 = MIC_X100_SBOX_BASE_ADDRESS + MIC_X100_SBOX_SIAC0;
+
+	reg = mic_mmio_read(mw, sice0);
+	reg |= MIC_X100_SBOX_DBR_BITS(0xf) | MIC_X100_SBOX_DMA_BITS(0xff);
+	mic_mmio_write(mw, reg, sice0);
+
+	/*
+	 * Enable auto-clear when enabling interrupts. Applicable only for
+	 * MSI-x. Legacy and MSI mode cannot have auto-clear enabled.
+	 */
+	if (mdev->irq_info.num_vectors > 1) {
+		reg = mic_mmio_read(mw, siac0);
+		reg |= MIC_X100_SBOX_DBR_BITS(0xf) |
+			MIC_X100_SBOX_DMA_BITS(0xff);
+		mic_mmio_write(mw, reg, siac0);
+	}
+}
+
+/**
+ * mic_x100_disable_interrupts - Disable interrupts.
+ * @mdev: pointer to mic_device instance
+ */
+static void mic_x100_disable_interrupts(struct mic_device *mdev)
+{
+	u32 reg;
+	struct mic_mw *mw = &mdev->mmio;
+	u32 sice0 = MIC_X100_SBOX_BASE_ADDRESS + MIC_X100_SBOX_SICE0;
+	u32 siac0 = MIC_X100_SBOX_BASE_ADDRESS + MIC_X100_SBOX_SIAC0;
+	u32 sicc0 = MIC_X100_SBOX_BASE_ADDRESS + MIC_X100_SBOX_SICC0;
+
+	reg = mic_mmio_read(mw, sice0);
+	mic_mmio_write(mw, reg, sicc0);
+
+	if (mdev->irq_info.num_vectors > 1) {
+		reg = mic_mmio_read(mw, siac0);
+		reg &= ~(MIC_X100_SBOX_DBR_BITS(0xf) |
+			MIC_X100_SBOX_DMA_BITS(0xff));
+		mic_mmio_write(mw, reg, siac0);
+	}
+}
+
+/**
+ * mic_x100_send_sbox_intr - Send an MIC_X100_SBOX interrupt to MIC.
+ * @mdev: pointer to mic_device instance
+ */
+static void mic_x100_send_sbox_intr(struct mic_device *mdev,
+			int doorbell)
+{
+	struct mic_mw *mw = &mdev->mmio;
+	u64 apic_icr_offset = MIC_X100_SBOX_APICICR0 + doorbell * 8;
+	u32 apicicr_low = mic_mmio_read(mw,
+			MIC_X100_SBOX_BASE_ADDRESS + apic_icr_offset);
+
+	/* for MIC we need to make sure we "hit" the send_icr bit (13) */
+	apicicr_low = (apicicr_low | (1 << 13));
+
+	/* Ensure that the interrupt is ordered w.r.t. previous stores. */
+	wmb();
+	mic_mmio_write(mw, apicicr_low,
+		MIC_X100_SBOX_BASE_ADDRESS + apic_icr_offset);
+}
+
+/**
+ * mic_x100_send_rdmasr_intr - Send an RDMASR interrupt to MIC.
+ * @mdev: pointer to mic_device instance
+ */
+static void mic_x100_send_rdmasr_intr(struct mic_device *mdev,
+			int doorbell)
+{
+	int rdmasr_offset = MIC_X100_SBOX_RDMASR0 + (doorbell << 2);
+	/* Ensure that the interrupt is ordered w.r.t. previous stores. */
+	wmb();
+	mic_mmio_write(&mdev->mmio, 0,
+		MIC_X100_SBOX_BASE_ADDRESS + rdmasr_offset);
+}
+
+/**
+ * __mic_x100_send_intr - Send interrupt to MIC.
+ * @mdev: pointer to mic_device instance
+ * @doorbell: doorbell number.
+ */
+static void mic_x100_send_intr(struct mic_device *mdev, int doorbell)
+{
+	int rdmasr_db;
+	if (doorbell < MIC_X100_NUM_SBOX_IRQ) {
+		mic_x100_send_sbox_intr(mdev, doorbell);
+	} else {
+		rdmasr_db = doorbell - MIC_X100_NUM_SBOX_IRQ +
+			MIC_X100_RDMASR_IRQ_BASE;
+		mic_x100_send_rdmasr_intr(mdev, rdmasr_db);
+	}
+}
+
+/**
+ * mic_ack_interrupt - Device specific interrupt handling.
+ * @mdev: pointer to mic_device instance
+ *
+ * Returns: bitmask of doorbell events triggered.
+ */
+static u32 mic_x100_ack_interrupt(struct mic_device *mdev)
+{
+	u32 reg = 0;
+	struct mic_mw *mw = &mdev->mmio;
+	u32 sicr0 = MIC_X100_SBOX_BASE_ADDRESS + MIC_X100_SBOX_SICR0;
+
+	/* Clear pending bit array. */
+	if (MIC_A0_STEP == mdev->stepping)
+		mic_mmio_write(mw, 1, MIC_X100_SBOX_BASE_ADDRESS +
+			MIC_X100_SBOX_MSIXPBACR);
+
+	if (mdev->irq_info.num_vectors <= 1) {
+		reg = mic_mmio_read(mw, sicr0);
+
+		if (unlikely(!reg))
+			goto done;
+
+		mic_mmio_write(mw, reg, sicr0);
+	}
+
+	if (mdev->stepping >= MIC_B0_STEP)
+		mdev->intr_ops->enable_interrupts(mdev);
+done:
+	return reg;
+}
+
+/**
+ * mic_x100_hw_intr_init - Initialize h/w specific interrupt
+ * information.
+ * @mdev: pointer to mic_device instance
+ */
+static void mic_x100_hw_intr_init(struct mic_device *mdev)
+{
+	mdev->intr_info = (struct mic_intr_info *) mic_x100_intr_init;
+}
+
+/**
+ * mic_x100_read_msi_to_src_map - read from the MSI mapping registers
+ * @mdev: pointer to mic_device instance
+ * @idx: index to the mapping register, 0 based
+ *
+ * This function allows reading of the 32bit MSI mapping register.
+ *
+ * RETURNS: The value in the register.
+ */
+static u32
+mic_x100_read_msi_to_src_map(struct mic_device *mdev, int idx)
+{
+	return mic_mmio_read(&mdev->mmio,
+		MIC_X100_SBOX_BASE_ADDRESS +
+		MIC_X100_SBOX_MXAR0 + idx * 4);
+}
+
+/**
+ * mic_x100_program_msi_to_src_map - program the MSI mapping registers
+ * @mdev: pointer to mic_device instance
+ * @idx: index to the mapping register, 0 based
+ * @offset: The bit offset in the register that needs to be updated.
+ * @set: boolean specifying if the bit in the specified offset needs
+ * to be set or cleared.
+ *
+ * RETURNS: None.
+ */
+static void
+mic_x100_program_msi_to_src_map(struct mic_device *mdev,
+			int idx, int offset, bool set)
+{
+	unsigned long reg;
+	struct mic_mw *mw = &mdev->mmio;
+	u32 mxar = MIC_X100_SBOX_BASE_ADDRESS +
+		MIC_X100_SBOX_MXAR0 + idx * 4;
+
+	reg = mic_mmio_read(mw, mxar);
+	if (set)
+		__set_bit(offset, &reg);
+	else
+		__clear_bit(offset, &reg);
+	mic_mmio_write(mw, reg, mxar);
+}
+
+/**
+ * mic_x100_smpt_set - Update an SMPT entry with a DMA address.
+ * @mdev: pointer to mic_device instance
+ *
+ * RETURNS: none.
+ */
+static void
+mic_x100_smpt_set(struct mic_device *mdev, dma_addr_t dma_addr, u8 index)
+{
+#define SNOOP_ON	(0 << 0)
+#define SNOOP_OFF	(1 << 0)
+/*
+ * Sbox Smpt Reg Bits:
+ * Bits	31:2	Host address
+ * Bits	1	RSVD
+ * Bits	0	No snoop
+ */
+#define BUILD_SMPT(NO_SNOOP, HOST_ADDR)  \
+	(u32)(((HOST_ADDR) << 2) | ((NO_SNOOP) & 0x01))
+
+	uint32_t smpt_reg_val = BUILD_SMPT(SNOOP_ON,
+			dma_addr >> mdev->smpt->info.page_shift);
+	mic_mmio_write(&mdev->mmio, smpt_reg_val,
+		MIC_X100_SBOX_BASE_ADDRESS +
+		MIC_X100_SBOX_SMPT00 + (4 * index));
+}
+
+/**
+ * mic_x100_smpt_hw_init - Initialize SMPT X100 specific fields.
+ * @mdev: pointer to mic_device instance
+ *
+ * RETURNS: none.
+ */
+static void mic_x100_smpt_hw_init(struct mic_device *mdev)
+{
+	struct mic_smpt_hw_info *info = &mdev->smpt->info;
+
+	info->num_reg = 32;
+	info->page_shift = 34;
+	info->page_size = (1ULL << info->page_shift);
+	info->base = 0x8000000000ULL;
+}
+
+struct mic_smpt_ops mic_x100_smpt_ops = {
+	.init = mic_x100_smpt_hw_init,
+	.set = mic_x100_smpt_set,
+};
+
 struct mic_hw_ops mic_x100_ops = {
 	.aper_bar = MIC_X100_APER_BAR,
 	.mmio_bar = MIC_X100_MMIO_BAR,
 	.read_spad = mic_x100_read_spad,
 	.write_spad = mic_x100_write_spad,
+	.send_intr = mic_x100_send_intr,
+	.ack_interrupt = mic_x100_ack_interrupt,
+};
+
+struct mic_hw_intr_ops mic_x100_intr_ops = {
+	.intr_init = mic_x100_hw_intr_init,
+	.enable_interrupts = mic_x100_enable_interrupts,
+	.disable_interrupts = mic_x100_disable_interrupts,
+	.program_msi_to_src_map = mic_x100_program_msi_to_src_map,
+	.read_msi_to_src_map = mic_x100_read_msi_to_src_map,
 };