From: Joerg Roedel Date: Wed, 6 Apr 2011 15:26:49 +0000 (+0200) Subject: x86/amd-iommu: Cleanup completion-wait handling X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=815b33fdc279d34ab40a8bfe1866623a4cc5669b;p=deliverable%2Flinux.git x86/amd-iommu: Cleanup completion-wait handling This patch cleans up the implementation of completion-wait command sending. It also switches the completion indicator from the MMIO bit to a memory store which can be checked without IOMMU locking. As a side effect this patch makes the __iommu_queue_command function obsolete and so it is removed too. Signed-off-by: Joerg Roedel --- diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c index f8ec28ea3314..073c64b1994b 100644 --- a/arch/x86/kernel/amd_iommu.c +++ b/arch/x86/kernel/amd_iommu.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #include @@ -34,7 +35,7 @@ #define CMD_SET_TYPE(cmd, t) ((cmd)->data[1] |= ((t) << 28)) -#define EXIT_LOOP_COUNT 10000000 +#define LOOP_TIMEOUT 100000 static DEFINE_RWLOCK(amd_iommu_devtable_lock); @@ -383,10 +384,14 @@ irqreturn_t amd_iommu_int_handler(int irq, void *data) * ****************************************************************************/ -static void build_completion_wait(struct iommu_cmd *cmd) +static void build_completion_wait(struct iommu_cmd *cmd, u64 address) { + WARN_ON(address & 0x7ULL); + memset(cmd, 0, sizeof(*cmd)); - cmd->data[0] = CMD_COMPL_WAIT_INT_MASK; + cmd->data[0] = lower_32_bits(__pa(address)) | CMD_COMPL_WAIT_STORE_MASK; + cmd->data[1] = upper_32_bits(__pa(address)); + cmd->data[2] = 1; CMD_SET_TYPE(cmd, CMD_COMPL_WAIT); } @@ -432,12 +437,14 @@ static void build_inv_iommu_pages(struct iommu_cmd *cmd, u64 address, * Writes the command to the IOMMUs command buffer and informs the * hardware about the new command. Must be called with iommu->lock held. */ -static int __iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd) +static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd) { + unsigned long flags; u32 tail, head; u8 *target; WARN_ON(iommu->cmd_buf_size & CMD_BUFFER_UNINITIALIZED); + spin_lock_irqsave(&iommu->lock, flags); tail = readl(iommu->mmio_base + MMIO_CMD_TAIL_OFFSET); target = iommu->cmd_buf + tail; memcpy_toio(target, cmd, sizeof(*cmd)); @@ -446,99 +453,41 @@ static int __iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd) if (tail == head) return -ENOMEM; writel(tail, iommu->mmio_base + MMIO_CMD_TAIL_OFFSET); - - return 0; -} - -/* - * General queuing function for commands. Takes iommu->lock and calls - * __iommu_queue_command(). - */ -static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd) -{ - unsigned long flags; - int ret; - - spin_lock_irqsave(&iommu->lock, flags); - ret = __iommu_queue_command(iommu, cmd); - if (!ret) - iommu->need_sync = true; + iommu->need_sync = true; spin_unlock_irqrestore(&iommu->lock, flags); - return ret; -} - -/* - * This function waits until an IOMMU has completed a completion - * wait command - */ -static void __iommu_wait_for_completion(struct amd_iommu *iommu) -{ - int ready = 0; - unsigned status = 0; - unsigned long i = 0; - - INC_STATS_COUNTER(compl_wait); - - while (!ready && (i < EXIT_LOOP_COUNT)) { - ++i; - /* wait for the bit to become one */ - status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET); - ready = status & MMIO_STATUS_COM_WAIT_INT_MASK; - } - - /* set bit back to zero */ - status &= ~MMIO_STATUS_COM_WAIT_INT_MASK; - writel(status, iommu->mmio_base + MMIO_STATUS_OFFSET); - - if (unlikely(i == EXIT_LOOP_COUNT)) - iommu->reset_in_progress = true; + return 0; } /* * This function queues a completion wait command into the command * buffer of an IOMMU */ -static int __iommu_completion_wait(struct amd_iommu *iommu) -{ - struct iommu_cmd cmd; - - build_completion_wait(&cmd); - - return __iommu_queue_command(iommu, &cmd); -} - -/* - * This function is called whenever we need to ensure that the IOMMU has - * completed execution of all commands we sent. It sends a - * COMPLETION_WAIT command and waits for it to finish. The IOMMU informs - * us about that by writing a value to a physical address we pass with - * the command. - */ static int iommu_completion_wait(struct amd_iommu *iommu) { - int ret = 0; - unsigned long flags; - - spin_lock_irqsave(&iommu->lock, flags); + struct iommu_cmd cmd; + volatile u64 sem = 0; + int ret, i = 0; if (!iommu->need_sync) - goto out; - - ret = __iommu_completion_wait(iommu); + return 0; - iommu->need_sync = false; + build_completion_wait(&cmd, (u64)&sem); + ret = iommu_queue_command(iommu, &cmd); if (ret) - goto out; - - __iommu_wait_for_completion(iommu); + return ret; -out: - spin_unlock_irqrestore(&iommu->lock, flags); + while (sem == 0 && i < LOOP_TIMEOUT) { + udelay(1); + i += 1; + } - if (iommu->reset_in_progress) + if (i == LOOP_TIMEOUT) { + pr_alert("AMD-Vi: Completion-Wait loop timed out\n"); + iommu->reset_in_progress = true; reset_iommu_command_buffer(iommu); + } return 0; }