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misc: pci_endpoint_test: Use memcpy_toio()/memcpy_fromio() for BAR tests

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The current code uses writel()/readl(), which has an implicit memory
barrier for every single readl()/writel().

Additionally, reading 4 bytes at a time over the PCI bus is not really
optimal, considering that this code is running in an ioctl handler.

Use memcpy_toio()/memcpy_fromio() for BAR tests.

Before patch with a 4MB BAR:

  $ time /usr/bin/pcitest -b 1
  BAR1:           OKAY
  real    0m 1.56s

After patch with a 4MB BAR:

  $ time /usr/bin/pcitest -b 1
  BAR1:           OKAY
  real    0m 0.54s

Link: https://lore.kernel.org/linux-pci/20240322164139.678228-1-cassel@kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
This commit is contained in:
Niklas Cassel 2024-03-22 17:41:38 +01:00 committed by Bjorn Helgaas
parent 199b03db86
commit 2a35703a6a
1 changed files with 42 additions and 12 deletions
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54
drivers/misc/pci_endpoint_test.c
View File

@ -7,6 +7,7 @@
*/
#include <linux/crc32.h>
#include <linux/cleanup.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/io.h>
@ -275,31 +276,60 @@ static const u32 bar_test_pattern[] = {
0xA5A5A5A5,
};
static int pci_endpoint_test_bar_memcmp(struct pci_endpoint_test *test,
enum pci_barno barno, int offset,
void *write_buf, void *read_buf,
int size)
{
memset(write_buf, bar_test_pattern[barno], size);
memcpy_toio(test->bar[barno] + offset, write_buf, size);
memcpy_fromio(read_buf, test->bar[barno] + offset, size);
return memcmp(write_buf, read_buf, size);
}
static bool pci_endpoint_test_bar(struct pci_endpoint_test *test,
enum pci_barno barno)
{
int j;
u32 val;
int size;
int j, bar_size, buf_size, iters, remain;
void *write_buf __free(kfree) = NULL;
void *read_buf __free(kfree) = NULL;
struct pci_dev *pdev = test->pdev;
if (!test->bar[barno])
return false;
size = pci_resource_len(pdev, barno);
bar_size = pci_resource_len(pdev, barno);
if (barno == test->test_reg_bar)
size = 0x4;
bar_size = 0x4;
for (j = 0; j < size; j += 4)
pci_endpoint_test_bar_writel(test, barno, j,
bar_test_pattern[barno]);
/*
* Allocate a buffer of max size 1MB, and reuse that buffer while
* iterating over the whole BAR size (which might be much larger).
*/
buf_size = min(SZ_1M, bar_size);
for (j = 0; j < size; j += 4) {
val = pci_endpoint_test_bar_readl(test, barno, j);
if (val != bar_test_pattern[barno])
write_buf = kmalloc(buf_size, GFP_KERNEL);
if (!write_buf)
return false;
read_buf = kmalloc(buf_size, GFP_KERNEL);
if (!read_buf)
return false;
iters = bar_size / buf_size;
for (j = 0; j < iters; j++)
if (pci_endpoint_test_bar_memcmp(test, barno, buf_size * j,
write_buf, read_buf, buf_size))
return false;
remain = bar_size % buf_size;
if (remain)
if (pci_endpoint_test_bar_memcmp(test, barno, buf_size * iters,
write_buf, read_buf, remain))
return false;
}
return true;
}