brcm2708: organize kernel patches

[openwrt/openwrt.git] / target / linux / brcm2708 / patches-4.19 / 950-0136-vchiq_2835_arm-Implement-a-DMA-pool-for-small-bulk-t.patch

diff --git a/target/linux/brcm2708/patches-4.19/950-0136-vchiq_2835_arm-Implement-a-DMA-pool-for-small-bulk-t.patch b/target/linux/brcm2708/patches-4.19/950-0136-vchiq_2835_arm-Implement-a-DMA-pool-for-small-bulk-t.patch
new file mode 100644 (file)
index 0000000..e6836b5
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.19/950-0136-vchiq_2835_arm-Implement-a-DMA-pool-for-small-bulk-t.patch
@@ -0,0 +1,126 @@
+From 75fdebcf15e8023b9640d9fc2e3ed227e5563968 Mon Sep 17 00:00:00 2001
+From: detule <ogjoneski@gmail.com>
+Date: Tue, 2 Oct 2018 04:10:08 -0400
+Subject: [PATCH] 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>
+@@ -60,6 +61,8 @@
+ #define BELL0 0x00
+ #define BELL2 0x08
+ 
++#define VCHIQ_DMA_POOL_SIZE PAGE_SIZE
++
+ struct vchiq_2835_state {
+       int inited;
+       VCHIQ_ARM_STATE_T arm_state;
+@@ -69,6 +72,7 @@ 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;
+@@ -91,6 +95,7 @@ static void __iomem *g_regs;
+  * relevant Device Tree node.
+  */
+ static unsigned int g_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;
+@@ -206,6 +211,14 @@ 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);
+@@ -397,9 +410,14 @@ 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?)
+@@ -419,6 +437,7 @@ 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;
+@@ -445,10 +464,16 @@ 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, "%s - %pK", __func__, pagelist);
+ 
+@@ -469,6 +494,7 @@ 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;