From: Rohit Thapliyal <r.thapliyal@xxxxxxxxxxx>
swiotlb default size of 64M is too big as
default value therefore it is made configurable
through command line through swiotlb_size parameter.
swiotlb allocation shall be done only when the
swiotlb size is given through command line.
Otherwise no swiotlb is allocated.
Signed-off-by: Rohit Thapliyal <r.thapliyal@xxxxxxxxxxx>
Signed-off-by: Manjeet Pawar <manjeet.p@xxxxxxxxxxx>
Reviewed-by: Akhilesh Kumar <akhilesh.k@xxxxxxxxxxx>
Reviewed-by: Ajeet Kumar Yadav <ajeet.y@xxxxxxxxxxx>
---
Documentation/kernel-parameters.txt | 3 +++
arch/arm64/mm/init.c | 3 ++-
include/linux/swiotlb.h | 1 +
lib/swiotlb.c | 33 +++++++++++++++++++++++++++++----
4 files changed, 35 insertions(+), 5 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 82b42c9..12b680f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3875,6 +3875,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
force -- force using of bounce buffers even if they
wouldn't be automatically used by the kernel
+ swiotlb_sz= [KNL] enter swiotlb size.
+ Sets the swiotlb size for eg. swiotlb_sz=64M
+
switches= [HW,M68k]
sysfs.deprecated=0|1 [KNL]
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index d45f862..89c6b39 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -403,7 +403,8 @@ static void __init free_unused_memmap(void)
*/
void __init mem_init(void)
{
- swiotlb_init(1);
+ if (swiotlb_enabled)
+ swiotlb_init(1);
set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 017fced..c7eb146 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -11,6 +11,7 @@ struct page;
struct scatterlist;
extern int swiotlb_force;
+extern int swiotlb_enabled;
/*
* Maximum allowable number of contiguous slabs to map,
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 76f29ec..e89296a 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -54,6 +54,7 @@
#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
int swiotlb_force;
+int swiotlb_enabled;
/*
* Used to do a quick range check in swiotlb_tbl_unmap_single and
@@ -96,6 +97,9 @@ static DEFINE_SPINLOCK(io_tlb_lock);
static int late_alloc;
+unsigned long swiotlb_sz;
+unsigned int swiotlb_sz_shift;
+
static int __init
setup_io_tlb_npages(char *str)
{
@@ -112,6 +116,24 @@ setup_io_tlb_npages(char *str)
return 0;
}
early_param("swiotlb", setup_io_tlb_npages);
+
+static int __init
+setup_io_tlb_size(char *str)
+{
+ int len = strlen(str);
+
+ if (str[len-1] == 'M')
+ swiotlb_sz_shift = 20;
+ else if (str[len-1] == 'K')
+ swiotlb_sz_shift = 10;
+ str[len-1] = '\0';
+ if (isdigit(*str))
+ swiotlb_sz = kstrtoul(str, &str, 0);
+
+ swiotlb_enabled = 1;
+ return 0;
+}
+early_param("swiotlb_sz", setup_io_tlb_size);
/* make io_tlb_overflow tunable too? */
unsigned long swiotlb_nr_tbl(void)
@@ -120,8 +142,9 @@ unsigned long swiotlb_nr_tbl(void)
}
EXPORT_SYMBOL_GPL(swiotlb_nr_tbl);
-/* default to 64MB */
-#define IO_TLB_DEFAULT_SIZE (64UL<<20)
+/* Pass from command line as swiotlb_sz=64M (for eg.)*/
+#define IO_TLB_DEFAULT_SIZE (swiotlb_sz<<swiotlb_sz_shift)
+
unsigned long swiotlb_size_or_default(void)
{
unsigned long size;
@@ -153,10 +176,12 @@ void swiotlb_print_info(void)
vstart = phys_to_virt(io_tlb_start);
vend = phys_to_virt(io_tlb_end);
- printk(KERN_INFO "software IO TLB [mem %#010llx-%#010llx] (%luMB) mapped at [%p-%p]\n",
+ pr_info("software IO TLB [mem %#010llx-%#010llx] (%lu%cB) mapped at [%p-%p]\n",
(unsigned long long)io_tlb_start,
(unsigned long long)io_tlb_end,
- bytes >> 20, vstart, vend - 1);
+ bytes >> swiotlb_sz_shift,
+ swiotlb_sz_shift == 20 ? 'M' : 'K',
+ vstart, vend - 1);
}
int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
--
1.7.9.5
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