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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 05/26] ARM: GICv3 ITS: introduce ITS command handling
On Fri, 31 Mar 2017, Andre Przywara wrote:
> 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>
Please address Julien's comments. In particular, cmd_lock needs to be
initialized here.
> ---
> xen/arch/arm/gic-v3-its.c | 182
> ++++++++++++++++++++++++++++++++++++++
> xen/arch/arm/gic-v3-lpi.c | 22 +++++
> xen/arch/arm/gic-v3.c | 25 +++++-
> xen/include/asm-arm/gic_v3_defs.h | 2 +
> xen/include/asm-arm/gic_v3_its.h | 38 ++++++++
> 5 files changed, 267 insertions(+), 2 deletions(-)
>
> diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
> index 9a86769..1ac598f 100644
> --- a/xen/arch/arm/gic-v3-its.c
> +++ b/xen/arch/arm/gic-v3-its.c
> @@ -19,11 +19,14 @@
> */
>
> #include <xen/lib.h>
> +#include <xen/delay.h>
> #include <xen/mm.h>
> #include <xen/sizes.h>
> +#include <asm/gic.h>
> #include <asm/gic_v3_defs.h>
> #include <asm/gic_v3_its.h>
> #include <asm/io.h>
> +#include <asm/page.h>
>
> #define ITS_CMD_QUEUE_SZ SZ_1M
>
> @@ -34,6 +37,147 @@ bool gicv3_its_host_has_its(void)
> return !list_empty(&host_its_list);
> }
>
> +#define BUFPTR_MASK GENMASK_ULL(19, 5)
> +static int its_send_command(struct host_its *hw_its, const void *its_cmd)
> +{
> + /* Some small grace period in case the command queue is congested. */
> + s_time_t deadline = NOW() + MILLISECS(1);
> + uint64_t readp, writep;
> + int ret = -EBUSY;
> +
> + /* No ITS commands from an interrupt handler (at the moment). */
> + ASSERT(!in_irq());
> +
> + spin_lock(&hw_its->cmd_lock);
> +
> + do {
> + readp = readq_relaxed(hw_its->its_base + GITS_CREADR) & BUFPTR_MASK;
> + writep = readq_relaxed(hw_its->its_base + GITS_CWRITER) &
> BUFPTR_MASK;
> +
> + if ( ((writep + ITS_CMD_SIZE) % ITS_CMD_QUEUE_SZ) != readp )
> + {
> + ret = 0;
> + break;
> + }
> +
> + /*
> + * If the command queue is full, wait for a bit in the hope it drains
> + * before giving up.
> + */
> + spin_unlock(&hw_its->cmd_lock);
> + cpu_relax();
> + udelay(1);
> + spin_lock(&hw_its->cmd_lock);
> + } while ( NOW() <= deadline );
> +
> + if ( ret )
> + {
> + spin_unlock(&hw_its->cmd_lock);
> + printk(XENLOG_WARNING "ITS: command queue full.\n");
> + return ret;
> + }
> +
> + memcpy(hw_its->cmd_buf + writep, its_cmd, ITS_CMD_SIZE);
> + if ( hw_its->flags & HOST_ITS_FLUSH_CMD_QUEUE )
> + clean_and_invalidate_dcache_va_range(hw_its->cmd_buf + writep,
> + ITS_CMD_SIZE);
> + else
> + dsb(ishst);
> +
> + writep = (writep + ITS_CMD_SIZE) % ITS_CMD_QUEUE_SZ;
> + writeq_relaxed(writep & BUFPTR_MASK, hw_its->its_base + GITS_CWRITER);
> +
> + spin_unlock(&hw_its->cmd_lock);
> +
> + return 0;
> +}
> +
> +/* Wait for an ITS to finish processing all commands. */
> +static int gicv3_its_wait_commands(struct host_its *hw_its)
> +{
> + /* Define an upper limit for our wait time. */
> + s_time_t deadline = NOW() + MILLISECS(100);
> + uint64_t readp, writep;
> +
> + do {
> + spin_lock(&hw_its->cmd_lock);
> + readp = readq_relaxed(hw_its->its_base + GITS_CREADR) & BUFPTR_MASK;
> + writep = readq_relaxed(hw_its->its_base + GITS_CWRITER) &
> BUFPTR_MASK;
> + spin_unlock(&hw_its->cmd_lock);
> +
> + if ( readp == writep )
> + return 0;
> +
> + cpu_relax();
> + udelay(1);
> + } while ( NOW() <= deadline );
> +
> + return -ETIMEDOUT;
> +}
> +
> +static uint64_t encode_rdbase(struct host_its *hw_its, unsigned int cpu,
> + uint64_t reg)
> +{
> + reg &= ~GENMASK_ULL(51, 16);
> +
> + reg |= gicv3_get_redist_address(cpu, hw_its->flags & HOST_ITS_USES_PTA);
> +
> + return reg;
> +}
> +
> +static int its_send_cmd_sync(struct host_its *its, unsigned 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, uint32_t collection_id,
> + unsigned int cpu)
> +{
> + uint64_t cmd[4];
> +
> + cmd[0] = GITS_CMD_MAPC;
> + cmd[1] = 0x00;
> + cmd[2] = encode_rdbase(its, cpu, collection_id);
> + cmd[2] |= GITS_VALID_BIT;
> + cmd[3] = 0x00;
> +
> + return its_send_command(its, cmd);
> +}
> +
> +/* Set up the (1:1) collection mapping for the given host CPU. */
> +int gicv3_its_setup_collection(unsigned int cpu)
> +{
> + struct host_its *its;
> + int ret;
> +
> + list_for_each_entry(its, &host_its_list, entry)
> + {
> + if ( !its->cmd_buf )
> + continue;
> +
> + ret = its_send_cmd_mapc(its, cpu, cpu);
> + if ( ret )
> + return ret;
> +
> + ret = its_send_cmd_sync(its, cpu);
> + if ( ret )
> + return ret;
> +
> + ret = gicv3_its_wait_commands(its);
> + if ( ret )
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> #define BASER_ATTR_MASK \
> ((0x3UL << GITS_BASER_SHAREABILITY_SHIFT) | \
> (0x7UL << GITS_BASER_OUTER_CACHEABILITY_SHIFT) | \
> @@ -178,6 +322,38 @@ retry:
> return -EINVAL;
> }
>
> +/*
> + * Before an ITS gets initialized, it should be in a quiescent state, where
> + * all outstanding commands and transactions have finished.
> + * So if the ITS is already enabled, turn it off and wait for all outstanding
> + * operations to get processed by polling the QUIESCENT bit.
> + */
> +static int gicv3_disable_its(struct host_its *hw_its)
> +{
> + uint32_t reg;
> + /* A similar generous wait limit as we use for the command queue wait. */
> + s_time_t deadline = NOW() + MILLISECS(100);
> +
> + reg = readl_relaxed(hw_its->its_base + GITS_CTLR);
> + if ( !(reg & GITS_CTLR_ENABLE) && (reg & GITS_CTLR_QUIESCENT) )
> + return 0;
> +
> + writel_relaxed(reg & ~GITS_CTLR_ENABLE, hw_its->its_base + GITS_CTLR);
> +
> + do {
> + reg = readl_relaxed(hw_its->its_base + GITS_CTLR);
> + if ( reg & GITS_CTLR_QUIESCENT )
> + return 0;
> +
> + cpu_relax();
> + udelay(1);
> + } while ( NOW() <= deadline );
> +
> + dprintk(XENLOG_ERR, "ITS not quiescent.\n");
> +
> + return -ETIMEDOUT;
> +}
> +
> /* Allow a user to limit the number of devices. */
> static unsigned int max_its_device_bits = 32;
> integer_param("max_its_device_bits", max_its_device_bits);
> @@ -191,9 +367,15 @@ static int gicv3_its_init_single_its(struct host_its
> *hw_its)
> if ( !hw_its->its_base )
> return -ENOMEM;
>
> + ret = gicv3_disable_its(hw_its);
> + if ( ret )
> + return ret;
> +
> reg = readq_relaxed(hw_its->its_base + GITS_TYPER);
> hw_its->devid_bits = GITS_TYPER_DEVICE_ID_BITS(reg);
> hw_its->devid_bits = min(hw_its->devid_bits, max_its_device_bits);
> + if ( reg & GITS_TYPER_PTA )
> + hw_its->flags |= HOST_ITS_USES_PTA;
>
> for ( i = 0; i < GITS_BASER_NR_REGS; i++ )
> {
> diff --git a/xen/arch/arm/gic-v3-lpi.c b/xen/arch/arm/gic-v3-lpi.c
> index 77f6009..d85d63d 100644
> --- a/xen/arch/arm/gic-v3-lpi.c
> +++ b/xen/arch/arm/gic-v3-lpi.c
> @@ -43,6 +43,8 @@ static struct {
> } lpi_data;
>
> struct lpi_redist_data {
> + paddr_t redist_addr;
> + unsigned int redist_id;
> void *pending_table;
> };
>
> @@ -50,6 +52,26 @@ static DEFINE_PER_CPU(struct lpi_redist_data, lpi_redist);
>
> #define MAX_PHYS_LPIS (lpi_data.nr_host_lpis - LPI_OFFSET)
>
> +/* Stores this redistributor's physical address and ID in a per-CPU variable
> */
> +void gicv3_set_redist_address(paddr_t address, unsigned int redist_id)
> +{
> + this_cpu(lpi_redist).redist_addr = address;
> + this_cpu(lpi_redist).redist_id = redist_id;
> +}
> +
> +/*
> + * Returns a redistributor's ID (either as an address or as an ID).
> + * This must be (and is) called only after it has been setup by the above
> + * function.
> + */
> +uint64_t gicv3_get_redist_address(unsigned int cpu, bool use_pta)
> +{
> + if ( use_pta )
> + return per_cpu(lpi_redist, cpu).redist_addr & GENMASK_ULL(51, 16);
> + else
> + return per_cpu(lpi_redist, cpu).redist_id << 16;
> +}
> +
> static int gicv3_lpi_allocate_pendtable(uint64_t *reg)
> {
> uint64_t val;
> diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
> index b84bc40..0e21cb2 100644
> --- a/xen/arch/arm/gic-v3.c
> +++ b/xen/arch/arm/gic-v3.c
> @@ -666,7 +666,21 @@ static int __init gicv3_populate_rdist(void)
>
> if ( typer & GICR_TYPER_PLPIS )
> {
> - int ret;
> + paddr_t rdist_addr;
> + int procnum, ret;
> +
> + /*
> + * 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.
> + */
> + rdist_addr = gicv3.rdist_regions[i].base;
> + rdist_addr += ptr - gicv3.rdist_regions[i].map_base;
> + procnum = (typer & GICR_TYPER_PROC_NUM_MASK);
> + procnum >>= GICR_TYPER_PROC_NUM_SHIFT;
> +
> + gicv3_set_redist_address(rdist_addr, procnum);
>
> ret = gicv3_lpi_init_rdist(ptr);
> if ( ret && ret != -ENODEV )
> @@ -705,7 +719,7 @@ static int __init gicv3_populate_rdist(void)
>
> static int gicv3_cpu_init(void)
> {
> - int i;
> + int i, ret;
> uint32_t priority;
>
> /* Register ourselves with the rest of the world */
> @@ -715,6 +729,13 @@ static int gicv3_cpu_init(void)
> if ( gicv3_enable_redist() )
> return -ENODEV;
>
> + if ( gicv3_its_host_has_its() )
> + {
> + ret = gicv3_its_setup_collection(smp_processor_id());
> + if ( ret )
> + return ret;
> + }
> +
> /* Set priority on PPI and SGI interrupts */
> priority = (GIC_PRI_IPI << 24 | GIC_PRI_IPI << 16 | GIC_PRI_IPI << 8 |
> GIC_PRI_IPI);
> diff --git a/xen/include/asm-arm/gic_v3_defs.h
> b/xen/include/asm-arm/gic_v3_defs.h
> index 7cdebc5..b01b6ed 100644
> --- a/xen/include/asm-arm/gic_v3_defs.h
> +++ b/xen/include/asm-arm/gic_v3_defs.h
> @@ -103,6 +103,8 @@
> #define GICR_TYPER_PLPIS (1U << 0)
> #define GICR_TYPER_VLPIS (1U << 1)
> #define GICR_TYPER_LAST (1U << 4)
> +#define GICR_TYPER_PROC_NUM_SHIFT 8
> +#define GICR_TYPER_PROC_NUM_MASK (0xffff << GICR_TYPER_PROC_NUM_SHIFT)
>
> /* For specifying the inner cacheability type only */
> #define GIC_BASER_CACHE_nCnB 0ULL
> diff --git a/xen/include/asm-arm/gic_v3_its.h
> b/xen/include/asm-arm/gic_v3_its.h
> index f21162a..4c2ae1c 100644
> --- a/xen/include/asm-arm/gic_v3_its.h
> +++ b/xen/include/asm-arm/gic_v3_its.h
> @@ -42,10 +42,12 @@
> #define GITS_CTLR_QUIESCENT BIT(31)
> #define GITS_CTLR_ENABLE BIT(0)
>
> +#define GITS_TYPER_PTA BIT_ULL(19)
> #define GITS_TYPER_DEVIDS_SHIFT 13
> #define GITS_TYPER_DEVIDS_MASK (0x1fUL << GITS_TYPER_DEVIDS_SHIFT)
> #define GITS_TYPER_DEVICE_ID_BITS(r) (((r & GITS_TYPER_DEVIDS_MASK) >> \
> GITS_TYPER_DEVIDS_SHIFT) + 1)
> +#define GITS_TYPER_IDBITS_SHIFT 8
>
> #define GITS_IIDR_VALUE 0x34c
>
> @@ -76,9 +78,26 @@
>
> #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
> +
> #include <xen/device_tree.h>
>
> #define HOST_ITS_FLUSH_CMD_QUEUE (1U << 0)
> +#define HOST_ITS_USES_PTA (1U << 1)
>
> /* data structure for each hardware ITS */
> struct host_its {
> @@ -88,6 +107,7 @@ struct host_its {
> paddr_t size;
> void __iomem *its_base;
> unsigned int devid_bits;
> + spinlock_t cmd_lock;
> void *cmd_buf;
> unsigned int flags;
> };
> @@ -108,6 +128,13 @@ int gicv3_lpi_init_rdist(void __iomem * rdist_base);
> int gicv3_lpi_init_host_lpis(unsigned int nr_lpis);
> int gicv3_its_init(void);
>
> +/* Store the physical address and ID for each redistributor as read from DT.
> */
> +void gicv3_set_redist_address(paddr_t address, unsigned int redist_id);
> +uint64_t gicv3_get_redist_address(unsigned int cpu, bool use_pta);
> +
> +/* Map a collection for this host CPU to each host ITS. */
> +int gicv3_its_setup_collection(unsigned int cpu);
> +
> #else
>
> static LIST_HEAD(host_its_list);
> @@ -135,6 +162,17 @@ static inline int gicv3_its_init(void)
> {
> return 0;
> }
> +
> +static inline void gicv3_set_redist_address(paddr_t address,
> + unsigned int redist_id)
> +{
> +}
> +
> +static inline int gicv3_its_setup_collection(unsigned int cpu)
> +{
> + return 0;
> +}
> +
> #endif /* CONFIG_HAS_ITS */
>
> #endif
> --
> 2.9.0
>
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