diff options
Diffstat (limited to 'drivers/misc/cxl/context.c')
| -rw-r--r-- | drivers/misc/cxl/context.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c new file mode 100644 index 00000000000..cca47210913 --- /dev/null +++ b/drivers/misc/cxl/context.c @@ -0,0 +1,193 @@ +/* + * Copyright 2014 IBM Corp. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/bitmap.h> +#include <linux/sched.h> +#include <linux/pid.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/debugfs.h> +#include <linux/slab.h> +#include <linux/idr.h> +#include <asm/cputable.h> +#include <asm/current.h> +#include <asm/copro.h> + +#include "cxl.h" + +/* + * Allocates space for a CXL context. + */ +struct cxl_context *cxl_context_alloc(void) +{ + return kzalloc(sizeof(struct cxl_context), GFP_KERNEL); +} + +/* + * Initialises a CXL context. + */ +int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master) +{ + int i; + + spin_lock_init(&ctx->sste_lock); + ctx->afu = afu; + ctx->master = master; + ctx->pid = NULL; /* Set in start work ioctl */ + + /* + * Allocate the segment table before we put it in the IDR so that we + * can always access it when dereferenced from IDR. For the same + * reason, the segment table is only destroyed after the context is + * removed from the IDR. Access to this in the IOCTL is protected by + * Linux filesytem symantics (can't IOCTL until open is complete). + */ + i = cxl_alloc_sst(ctx); + if (i) + return i; + + INIT_WORK(&ctx->fault_work, cxl_handle_fault); + + init_waitqueue_head(&ctx->wq); + spin_lock_init(&ctx->lock); + + ctx->irq_bitmap = NULL; + ctx->pending_irq = false; + ctx->pending_fault = false; + ctx->pending_afu_err = false; + + /* + * When we have to destroy all contexts in cxl_context_detach_all() we + * end up with afu_release_irqs() called from inside a + * idr_for_each_entry(). Hence we need to make sure that anything + * dereferenced from this IDR is ok before we allocate the IDR here. + * This clears out the IRQ ranges to ensure this. + */ + for (i = 0; i < CXL_IRQ_RANGES; i++) + ctx->irqs.range[i] = 0; + + mutex_init(&ctx->status_mutex); + + ctx->status = OPENED; + + /* + * Allocating IDR! We better make sure everything's setup that + * dereferences from it. + */ + idr_preload(GFP_KERNEL); + spin_lock(&afu->contexts_lock); + i = idr_alloc(&ctx->afu->contexts_idr, ctx, 0, + ctx->afu->num_procs, GFP_NOWAIT); + spin_unlock(&afu->contexts_lock); + idr_preload_end(); + if (i < 0) + return i; + + ctx->pe = i; + ctx->elem = &ctx->afu->spa[i]; + ctx->pe_inserted = false; + return 0; +} + +/* + * Map a per-context mmio space into the given vma. + */ +int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma) +{ + u64 len = vma->vm_end - vma->vm_start; + len = min(len, ctx->psn_size); + + if (ctx->afu->current_mode == CXL_MODE_DEDICATED) { + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + return vm_iomap_memory(vma, ctx->afu->psn_phys, ctx->afu->adapter->ps_size); + } + + /* make sure there is a valid per process space for this AFU */ + if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) { + pr_devel("AFU doesn't support mmio space\n"); + return -EINVAL; + } + + /* Can't mmap until the AFU is enabled */ + if (!ctx->afu->enabled) + return -EBUSY; + + pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__, + ctx->psn_phys, ctx->pe , ctx->master); + + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + return vm_iomap_memory(vma, ctx->psn_phys, len); +} + +/* + * Detach a context from the hardware. This disables interrupts and doesn't + * return until all outstanding interrupts for this context have completed. The + * hardware should no longer access *ctx after this has returned. + */ +static void __detach_context(struct cxl_context *ctx) +{ + enum cxl_context_status status; + + mutex_lock(&ctx->status_mutex); + status = ctx->status; + ctx->status = CLOSED; + mutex_unlock(&ctx->status_mutex); + if (status != STARTED) + return; + + WARN_ON(cxl_detach_process(ctx)); + afu_release_irqs(ctx); + flush_work(&ctx->fault_work); /* Only needed for dedicated process */ + wake_up_all(&ctx->wq); +} + +/* + * Detach the given context from the AFU. This doesn't actually + * free the context but it should stop the context running in hardware + * (ie. prevent this context from generating any further interrupts + * so that it can be freed). + */ +void cxl_context_detach(struct cxl_context *ctx) +{ + __detach_context(ctx); +} + +/* + * Detach all contexts on the given AFU. + */ +void cxl_context_detach_all(struct cxl_afu *afu) +{ + struct cxl_context *ctx; + int tmp; + + rcu_read_lock(); + idr_for_each_entry(&afu->contexts_idr, ctx, tmp) + /* + * Anything done in here needs to be setup before the IDR is + * created and torn down after the IDR removed + */ + __detach_context(ctx); + rcu_read_unlock(); +} + +void cxl_context_free(struct cxl_context *ctx) +{ + spin_lock(&ctx->afu->contexts_lock); + idr_remove(&ctx->afu->contexts_idr, ctx->pe); + spin_unlock(&ctx->afu->contexts_lock); + synchronize_rcu(); + + free_page((u64)ctx->sstp); + ctx->sstp = NULL; + + put_pid(ctx->pid); + kfree(ctx); +} |