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[Xen-devel] [RFC PATCH v2 05/26] ARM: GICv3 ITS: introduce ITS command handling



To be able to easily send commands to the ITS, create the respective
wrapper functions, which take care of the ring buffer.
The first two commands we implement provide methods to map a collection
to a redistributor (aka host core) and to flush the command queue (SYNC).
Start using these commands for mapping one collection to each host CPU.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
 xen/arch/arm/gic-its.c        | 100 ++++++++++++++++++++++++++++++++++++++++++
 xen/arch/arm/gic-v3.c         |  15 +++++++
 xen/include/asm-arm/gic-its.h |  33 ++++++++++++++
 3 files changed, 148 insertions(+)

diff --git a/xen/arch/arm/gic-its.c b/xen/arch/arm/gic-its.c
index 2fb3bcb..d0f5fd1 100644
--- a/xen/arch/arm/gic-its.c
+++ b/xen/arch/arm/gic-its.c
@@ -34,6 +34,10 @@ static struct {
     unsigned int host_lpi_bits;
 } lpi_data;
 
+/* Physical redistributor address */
+static DEFINE_PER_CPU(uint64_t, rdist_addr);
+/* Redistributor ID */
+static DEFINE_PER_CPU(uint64_t, rdist_id);
 /* Pending table for each redistributor */
 static DEFINE_PER_CPU(void *, pending_table);
 
@@ -41,6 +45,85 @@ static DEFINE_PER_CPU(void *, pending_table);
 
 #define ITS_CMD_QUEUE_SZ                                SZ_64K
 
+static int its_send_command(struct host_its *hw_its, void *its_cmd)
+{
+    uint64_t readp, writep;
+
+    spin_lock(&hw_its->cmd_lock);
+
+    readp = readq_relaxed(hw_its->its_base + GITS_CREADR) & GENMASK(19, 5);
+    writep = readq_relaxed(hw_its->its_base + GITS_CWRITER) & GENMASK(19, 5);
+
+    if ( ((writep + ITS_CMD_SIZE) % ITS_CMD_QUEUE_SZ) == readp )
+    {
+        spin_unlock(&hw_its->cmd_lock);
+        return -EBUSY;
+    }
+
+    memcpy(hw_its->cmd_buf + writep, its_cmd, ITS_CMD_SIZE);
+    __flush_dcache_area(hw_its->cmd_buf + writep, ITS_CMD_SIZE);
+    writep = (writep + ITS_CMD_SIZE) % ITS_CMD_QUEUE_SZ;
+
+    writeq_relaxed(writep & GENMASK(19, 5), hw_its->its_base + GITS_CWRITER);
+
+    spin_unlock(&hw_its->cmd_lock);
+
+    return 0;
+}
+
+static uint64_t encode_rdbase(struct host_its *hw_its, int cpu, uint64_t reg)
+{
+    reg &= ~GENMASK(51, 16);
+
+    if ( hw_its->pta )
+        reg |= per_cpu(rdist_addr, cpu) & GENMASK(51, 16);
+    else
+        reg |= per_cpu(rdist_id, cpu) << 16;
+
+    return reg;
+}
+
+static int its_send_cmd_sync(struct host_its *its, int cpu)
+{
+    uint64_t cmd[4];
+
+    cmd[0] = GITS_CMD_SYNC;
+    cmd[1] = 0x00;
+    cmd[2] = encode_rdbase(its, cpu, 0x0);
+    cmd[3] = 0x00;
+
+    return its_send_command(its, cmd);
+}
+
+static int its_send_cmd_mapc(struct host_its *its, int collection_id, int cpu)
+{
+    uint64_t cmd[4];
+
+    cmd[0] = GITS_CMD_MAPC;
+    cmd[1] = 0x00;
+    cmd[2] = encode_rdbase(its, cpu, (collection_id & GENMASK(15, 0)));
+    cmd[2] |= BIT_ULL(63);
+    cmd[3] = 0x00;
+
+    return its_send_command(its, cmd);
+}
+
+/* Set up the (1:1) collection mapping for the given host CPU. */
+void gicv3_its_setup_collection(int cpu)
+{
+    struct host_its *its;
+
+    list_for_each_entry(its, &host_its_list, entry)
+    {
+        /* Only send commands to ITS that have been initialized already. */
+        if ( !its->cmd_buf )
+            continue;
+
+        its_send_cmd_mapc(its, cpu, cpu);
+        its_send_cmd_sync(its, cpu);
+    }
+}
+
 #define BASER_ATTR_MASK                                           \
         ((0x3UL << GITS_BASER_SHAREABILITY_SHIFT)               | \
          (0x7UL << GITS_BASER_OUTER_CACHEABILITY_SHIFT)         | \
@@ -148,6 +231,13 @@ int gicv3_its_init(struct host_its *hw_its)
     if ( !hw_its->its_base )
         return -ENOMEM;
 
+    /* Make sure the ITS is disabled before programming the BASE registers. */
+    reg = readl_relaxed(hw_its->its_base + GITS_CTLR);
+    writel_relaxed(reg & ~GITS_CTLR_ENABLE, hw_its->its_base + GITS_CTLR);
+
+    reg = readq_relaxed(hw_its->its_base + GITS_TYPER);
+    hw_its->pta = !!(reg & GITS_TYPER_PTA);
+
     for ( i = 0; i < GITS_BASER_NR_REGS; i++ )
     {
         void __iomem *basereg = hw_its->its_base + GITS_BASER0 + i * 8;
@@ -175,9 +265,18 @@ int gicv3_its_init(struct host_its *hw_its)
     if ( !hw_its->cmd_buf )
         return -ENOMEM;
 
+    its_send_cmd_mapc(hw_its, smp_processor_id(), smp_processor_id());
+    its_send_cmd_sync(hw_its, smp_processor_id());
+
     return 0;
 }
 
+void gicv3_set_redist_addr(paddr_t address, int redist_id)
+{
+    this_cpu(rdist_addr) = address;
+    this_cpu(rdist_id) = redist_id;
+}
+
 uint64_t gicv3_lpi_allocate_pendtable(void)
 {
     uint64_t reg, attr;
@@ -286,6 +385,7 @@ void gicv3_its_dt_init(const struct dt_device_node *node)
         its_data->addr = addr;
         its_data->size = size;
         its_data->dt_node = its;
+        spin_lock_init(&its_data->cmd_lock);
 
         printk("GICv3: Found ITS @0x%lx\n", addr);
 
diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index 8ca7da2..d2461cb 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -643,6 +643,8 @@ static int gicv3_rdist_init_lpis(void __iomem * rdist_base)
         return -ENOMEM;
     writeq_relaxed(table_reg, rdist_base + GICR_PROPBASER);
 
+    gicv3_its_setup_collection(smp_processor_id());
+
     return 0;
 }
 
@@ -691,8 +693,21 @@ static int __init gicv3_populate_rdist(void)
 
                 if ( typer & GICR_TYPER_PLPIS )
                 {
+                    paddr_t rdist_addr;
                     int ret;
 
+                    rdist_addr = gicv3.rdist_regions[i].base;
+                    rdist_addr += ptr - gicv3.rdist_regions[i].map_base;
+
+                    /* The ITS refers to redistributors either by their 
physical
+                     * address or by their ID. Determine those two values and
+                     * let the ITS code store them in per host CPU variables to
+                     * later be able to address those redistributors.
+                     */
+                    gicv3_set_redist_addr(rdist_addr,
+                                          (typer >> GITS_TYPER_IDBITS_SHIFT) &
+                                          GENMASK(15, 0));
+
                     ret = gicv3_rdist_init_lpis(ptr);
                     if ( ret && ret != -ENODEV )
                     {
diff --git a/xen/include/asm-arm/gic-its.h b/xen/include/asm-arm/gic-its.h
index e0fded8..68e5f63 100644
--- a/xen/include/asm-arm/gic-its.h
+++ b/xen/include/asm-arm/gic-its.h
@@ -38,6 +38,8 @@
 
 /* Register bits */
 #define GITS_CTLR_ENABLE                BIT_ULL(0)
+#define GITS_TYPER_PTA                  BIT_ULL(19)
+#define GITS_TYPER_IDBITS_SHIFT         8
 #define GITS_IIDR_VALUE                 0x34c
 
 #define GITS_BASER_VALID                BIT_ULL(63)
@@ -63,6 +65,22 @@
 
 #define GITS_CBASER_SIZE_MASK           0xff
 
+/* ITS command definitions */
+#define ITS_CMD_SIZE                    32
+
+#define GITS_CMD_MOVI                   0x01
+#define GITS_CMD_INT                    0x03
+#define GITS_CMD_CLEAR                  0x04
+#define GITS_CMD_SYNC                   0x05
+#define GITS_CMD_MAPD                   0x08
+#define GITS_CMD_MAPC                   0x09
+#define GITS_CMD_MAPTI                  0x0a
+#define GITS_CMD_MAPI                   0x0b
+#define GITS_CMD_INV                    0x0c
+#define GITS_CMD_INVALL                 0x0d
+#define GITS_CMD_MOVALL                 0x0e
+#define GITS_CMD_DISCARD                0x0f
+
 #ifndef __ASSEMBLY__
 #include <xen/device_tree.h>
 
@@ -73,7 +91,9 @@ struct host_its {
     paddr_t addr;
     paddr_t size;
     void __iomem *its_base;
+    spinlock_t cmd_lock;
     void *cmd_buf;
+    bool pta;
 };
 
 extern struct list_head host_its_list;
@@ -93,6 +113,12 @@ uint64_t gicv3_lpi_allocate_pendtable(void);
 int gicv3_lpi_init_host_lpis(unsigned int nr_lpis);
 int gicv3_its_init(struct host_its *hw_its);
 
+/* Set the physical address and ID for each redistributor as read from DT. */
+void gicv3_set_redist_addr(paddr_t address, int redist_id);
+
+/* Map a collection for this host CPU to each host ITS. */
+void gicv3_its_setup_collection(int cpu);
+
 #else
 
 static inline void gicv3_its_dt_init(const struct dt_device_node *node)
@@ -114,6 +140,13 @@ static inline int gicv3_its_init(struct host_its *hw_its)
 {
     return 0;
 }
+static inline void gicv3_set_redist_addr(paddr_t address, int redist_id)
+{
+}
+static inline void gicv3_its_setup_collection(int cpu)
+{
+}
+
 #endif /* CONFIG_HAS_ITS */
 
 #endif /* __ASSEMBLY__ */
-- 
2.9.0


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