diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.14/950-0424-vchiq_2835_arm-Implement-a-DMA-pool-for-small-bulk-t.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.14/950-0424-vchiq_2835_arm-Implement-a-DMA-pool-for-small-bulk-t.patch | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.14/950-0424-vchiq_2835_arm-Implement-a-DMA-pool-for-small-bulk-t.patch b/target/linux/brcm2708/patches-4.14/950-0424-vchiq_2835_arm-Implement-a-DMA-pool-for-small-bulk-t.patch new file mode 100644 index 0000000000..0c93a14dc0 --- /dev/null +++ b/target/linux/brcm2708/patches-4.14/950-0424-vchiq_2835_arm-Implement-a-DMA-pool-for-small-bulk-t.patch @@ -0,0 +1,126 @@ +From 88acd92a7cbcb8a6ae299b88554abbc9bedbae0a Mon Sep 17 00:00:00 2001 +From: detule <ogjoneski@gmail.com> +Date: Tue, 2 Oct 2018 04:10:08 -0400 +Subject: [PATCH 424/454] vchiq_2835_arm: Implement a DMA pool for small bulk + transfers (#2699) + +During a bulk transfer we request a DMA allocation to hold the +scatter-gather list. Most of the time, this allocation is small +(<< PAGE_SIZE), however it can be requested at a high enough frequency +to cause fragmentation and/or stress the CMA allocator (think time +spent in compaction here, or during allocations elsewhere). + +Implement a pool to serve up small DMA allocations, falling back +to a coherent allocation if the request is greater than +VCHIQ_DMA_POOL_SIZE. + +Signed-off-by: Oliver Gjoneski <ogjoneski@gmail.com> +--- + .../interface/vchiq_arm/vchiq_2835_arm.c | 40 +++++++++++++++---- + 1 file changed, 33 insertions(+), 7 deletions(-) + +--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c ++++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c +@@ -37,6 +37,7 @@ + #include <linux/interrupt.h> + #include <linux/pagemap.h> + #include <linux/dma-mapping.h> ++#include <linux/dmapool.h> + #include <linux/io.h> + #include <linux/platform_device.h> + #include <linux/uaccess.h> +@@ -59,6 +60,8 @@ + #define BELL0 0x00 + #define BELL2 0x08 + ++#define VCHIQ_DMA_POOL_SIZE PAGE_SIZE ++ + typedef struct vchiq_2835_state_struct { + int inited; + VCHIQ_ARM_STATE_T arm_state; +@@ -68,6 +71,7 @@ struct vchiq_pagelist_info { + PAGELIST_T *pagelist; + size_t pagelist_buffer_size; + dma_addr_t dma_addr; ++ bool is_from_pool; + enum dma_data_direction dma_dir; + unsigned int num_pages; + unsigned int pages_need_release; +@@ -78,6 +82,7 @@ struct vchiq_pagelist_info { + + static void __iomem *g_regs; + static unsigned int g_cache_line_size = sizeof(CACHE_LINE_SIZE); ++static struct dma_pool *g_dma_pool; + static unsigned int g_fragments_size; + static char *g_fragments_base; + static char *g_free_fragments; +@@ -193,6 +198,14 @@ int vchiq_platform_init(struct platform_ + } + + g_dev = dev; ++ g_dma_pool = dmam_pool_create("vchiq_scatter_pool", dev, ++ VCHIQ_DMA_POOL_SIZE, g_cache_line_size, ++ 0); ++ if (!g_dma_pool) { ++ dev_err(dev, "failed to create dma pool"); ++ return -ENOMEM; ++ } ++ + vchiq_log_info(vchiq_arm_log_level, + "vchiq_init - done (slots %pK, phys %pad)", + vchiq_slot_zero, &slot_phys); +@@ -377,9 +390,14 @@ cleanup_pagelistinfo(struct vchiq_pageli + for (i = 0; i < pagelistinfo->num_pages; i++) + put_page(pagelistinfo->pages[i]); + } +- +- dma_free_coherent(g_dev, pagelistinfo->pagelist_buffer_size, +- pagelistinfo->pagelist, pagelistinfo->dma_addr); ++ if (pagelistinfo->is_from_pool) { ++ dma_pool_free(g_dma_pool, pagelistinfo->pagelist, ++ pagelistinfo->dma_addr); ++ } else { ++ dma_free_coherent(g_dev, pagelistinfo->pagelist_buffer_size, ++ pagelistinfo->pagelist, ++ pagelistinfo->dma_addr); ++ } + } + + /* There is a potential problem with partial cache lines (pages?) +@@ -400,6 +418,7 @@ create_pagelist(char __user *buf, size_t + u32 *addrs; + unsigned int num_pages, offset, i, k; + int actual_pages; ++ bool is_from_pool; + size_t pagelist_size; + struct scatterlist *scatterlist, *sg; + int dma_buffers; +@@ -417,10 +436,16 @@ create_pagelist(char __user *buf, size_t + /* Allocate enough storage to hold the page pointers and the page + ** list + */ +- pagelist = dma_zalloc_coherent(g_dev, +- pagelist_size, +- &dma_addr, +- GFP_KERNEL); ++ if (pagelist_size > VCHIQ_DMA_POOL_SIZE) { ++ pagelist = dma_zalloc_coherent(g_dev, ++ pagelist_size, ++ &dma_addr, ++ GFP_KERNEL); ++ is_from_pool = false; ++ } else { ++ pagelist = dma_pool_zalloc(g_dma_pool, GFP_KERNEL, &dma_addr); ++ is_from_pool = true; ++ } + + vchiq_log_trace(vchiq_arm_log_level, "create_pagelist - %pK", + pagelist); +@@ -441,6 +466,7 @@ create_pagelist(char __user *buf, size_t + pagelistinfo->pagelist = pagelist; + pagelistinfo->pagelist_buffer_size = pagelist_size; + pagelistinfo->dma_addr = dma_addr; ++ pagelistinfo->is_from_pool = is_from_pool; + pagelistinfo->dma_dir = (type == PAGELIST_WRITE) ? + DMA_TO_DEVICE : DMA_FROM_DEVICE; + pagelistinfo->num_pages = num_pages; |