ocxl: Initiate a TLB invalidate command

When a TLB Invalidate is required for the Logical Partition, the following
sequence has to be performed:

1. Load MMIO ATSD AVA register with the necessary value, if required.
2. Write the MMIO ATSD launch register to initiate the TLB Invalidate
command.
3. Poll the MMIO ATSD status register to determine when the TLB Invalidate
   has been completed.

Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com>
Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201125155013.39955-3-clombard@linux.vnet.ibm.com

arch/powerpc/include/asm/pnv-ocxl.h

@@ -3,12 +3,59 @@
 #ifndef _ASM_PNV_OCXL_H
 #define _ASM_PNV_OCXL_H
 
+#include <linux/bitfield.h>
 #include <linux/pci.h>
 
 #define PNV_OCXL_TL_MAX_TEMPLATE        63
 #define PNV_OCXL_TL_BITS_PER_RATE       4
 #define PNV_OCXL_TL_RATE_BUF_SIZE       ((PNV_OCXL_TL_MAX_TEMPLATE+1) * PNV_OCXL_TL_BITS_PER_RATE / 8)
 
+#define PNV_OCXL_ATSD_TIMEOUT		1
+
+/* TLB Management Instructions */
+#define PNV_OCXL_ATSD_LNCH		0x00
+/* Radix Invalidate */
+#define   PNV_OCXL_ATSD_LNCH_R		PPC_BIT(0)
+/* Radix Invalidation Control
+ * 0b00 Just invalidate TLB.
+ * 0b01 Invalidate just Page Walk Cache.
+ * 0b10 Invalidate TLB, Page Walk Cache, and any
+ * caching of Partition and Process Table Entries.
+ */
+#define   PNV_OCXL_ATSD_LNCH_RIC	PPC_BITMASK(1, 2)
+/* Number and Page Size of translations to be invalidated */
+#define   PNV_OCXL_ATSD_LNCH_LP		PPC_BITMASK(3, 10)
+/* Invalidation Criteria
+ * 0b00 Invalidate just the target VA.
+ * 0b01 Invalidate matching PID.
+ */
+#define   PNV_OCXL_ATSD_LNCH_IS		PPC_BITMASK(11, 12)
+/* 0b1: Process Scope, 0b0: Partition Scope */
+#define   PNV_OCXL_ATSD_LNCH_PRS	PPC_BIT(13)
+/* Invalidation Flag */
+#define   PNV_OCXL_ATSD_LNCH_B		PPC_BIT(14)
+/* Actual Page Size to be invalidated
+ * 000 4KB
+ * 101 64KB
+ * 001 2MB
+ * 010 1GB
+ */
+#define   PNV_OCXL_ATSD_LNCH_AP		PPC_BITMASK(15, 17)
+/* Defines the large page select
+ * L=0b0 for 4KB pages
+ * L=0b1 for large pages)
+ */
+#define   PNV_OCXL_ATSD_LNCH_L		PPC_BIT(18)
+/* Process ID */
+#define   PNV_OCXL_ATSD_LNCH_PID	PPC_BITMASK(19, 38)
+/* NoFlush – Assumed to be 0b0 */
+#define   PNV_OCXL_ATSD_LNCH_F		PPC_BIT(39)
+#define   PNV_OCXL_ATSD_LNCH_OCAPI_SLBI	PPC_BIT(40)
+#define   PNV_OCXL_ATSD_LNCH_OCAPI_SINGLETON	PPC_BIT(41)
+#define PNV_OCXL_ATSD_AVA		0x08
+#define   PNV_OCXL_ATSD_AVA_AVA		PPC_BITMASK(0, 51)
+#define PNV_OCXL_ATSD_STAT		0x10
+
 int pnv_ocxl_get_actag(struct pci_dev *dev, u16 *base, u16 *enabled, u16 *supported);
 int pnv_ocxl_get_pasid_count(struct pci_dev *dev, int *count);
 
@@ -31,4 +78,8 @@ int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int pe_handle);
 int pnv_ocxl_map_lpar(struct pci_dev *dev, uint64_t lparid,
 		      uint64_t lpcr, void __iomem **arva);
 void pnv_ocxl_unmap_lpar(void __iomem *arva);
+void pnv_ocxl_tlb_invalidate(void __iomem *arva,
+			     unsigned long pid,
+			     unsigned long addr,
+			     unsigned long page_size);
 #endif /* _ASM_PNV_OCXL_H */

arch/powerpc/platforms/powernv/ocxl.c

@@ -528,3 +528,72 @@ void pnv_ocxl_unmap_lpar(void __iomem *arva)
 	iounmap(arva);
 }
 EXPORT_SYMBOL_GPL(pnv_ocxl_unmap_lpar);
+
+void pnv_ocxl_tlb_invalidate(void __iomem *arva,
+			     unsigned long pid,
+			     unsigned long addr,
+			     unsigned long page_size)
+{
+	unsigned long timeout = jiffies + (HZ * PNV_OCXL_ATSD_TIMEOUT);
+	u64 val = 0ull;
+	int pend;
+	u8 size;
+
+	if (!(arva))
+		return;
+
+	if (addr) {
+		/* load Abbreviated Virtual Address register with
+		 * the necessary value
+		 */
+		val |= FIELD_PREP(PNV_OCXL_ATSD_AVA_AVA, addr >> (63-51));
+		out_be64(arva + PNV_OCXL_ATSD_AVA, val);
+	}
+
+	/* Write access initiates a shoot down to initiate the
+	 * TLB Invalidate command
+	 */
+	val = PNV_OCXL_ATSD_LNCH_R;
+	val |= FIELD_PREP(PNV_OCXL_ATSD_LNCH_RIC, 0b10);
+	if (addr)
+		val |= FIELD_PREP(PNV_OCXL_ATSD_LNCH_IS, 0b00);
+	else {
+		val |= FIELD_PREP(PNV_OCXL_ATSD_LNCH_IS, 0b01);
+		val |= PNV_OCXL_ATSD_LNCH_OCAPI_SINGLETON;
+	}
+	val |= PNV_OCXL_ATSD_LNCH_PRS;
+	/* Actual Page Size to be invalidated
+	 * 000 4KB
+	 * 101 64KB
+	 * 001 2MB
+	 * 010 1GB
+	 */
+	size = 0b101;
+	if (page_size == 0x1000)
+		size = 0b000;
+	if (page_size == 0x200000)
+		size = 0b001;
+	if (page_size == 0x40000000)
+		size = 0b010;
+	val |= FIELD_PREP(PNV_OCXL_ATSD_LNCH_AP, size);
+	val |= FIELD_PREP(PNV_OCXL_ATSD_LNCH_PID, pid);
+	out_be64(arva + PNV_OCXL_ATSD_LNCH, val);
+
+	/* Poll the ATSD status register to determine when the
+	 * TLB Invalidate has been completed.
+	 */
+	val = in_be64(arva + PNV_OCXL_ATSD_STAT);
+	pend = val >> 63;
+
+	while (pend) {
+		if (time_after_eq(jiffies, timeout)) {
+			pr_err("%s - Timeout while reading XTS MMIO ATSD status register (val=%#llx, pidr=0x%lx)\n",
+			       __func__, val, pid);
+			return;
+		}
+		cpu_relax();
+		val = in_be64(arva + PNV_OCXL_ATSD_STAT);
+		pend = val >> 63;
+	}
+}
+EXPORT_SYMBOL_GPL(pnv_ocxl_tlb_invalidate);