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authorAlexandre Bounine <alexandre.bounine@idt.com>2016-08-02 21:06:40 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2016-08-02 23:35:34 (GMT)
commitcb782cdd2ffffbf7fd17e4aefb20f4db5c67caeb (patch)
treee5e2096ca162c5b433850aaab8731f9281a475cb /drivers/rapidio
parent4498c31adff99d243b34b0bf39363a35ea070928 (diff)
rapidio/tsi721: add PCIe MRRS override parameter
Add PCIe Maximum Read Request Size (MRRS) adjustment parameter to allow users to override configuration register value set during PCIe bus initialization. Performance of Tsi721 device as PCIe bus master can be improved if MRRS is set to its maximum value (4096 bytes). Some platforms have limitations for supported MRRS and therefore the default value should be preserved, unless it is known that given platform supports full set of MRRS values defined by PCI Express specification. Link: http://lkml.kernel.org/r/1469125134-16523-6-git-send-email-alexandre.bounine@idt.com Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com> Cc: Matt Porter <mporter@kernel.crashing.org> Cc: Andre van Herk <andre.van.herk@prodrive-technologies.com> Cc: Barry Wood <barry.wood@idt.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/rapidio')
-rw-r--r--drivers/rapidio/devices/tsi721.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/drivers/rapidio/devices/tsi721.c b/drivers/rapidio/devices/tsi721.c
index 4c20e99..85098f8 100644
--- a/drivers/rapidio/devices/tsi721.c
+++ b/drivers/rapidio/devices/tsi721.c
@@ -37,11 +37,15 @@
#include "tsi721.h"
#ifdef DEBUG
-u32 dbg_level = DBG_INIT | DBG_EXIT;
+u32 dbg_level;
module_param(dbg_level, uint, S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(dbg_level, "Debugging output level (default 0 = none)");
#endif
+static int pcie_mrrs = -1;
+module_param(pcie_mrrs, int, S_IRUGO);
+MODULE_PARM_DESC(pcie_mrrs, "PCIe MRRS override value (0...5)");
+
static void tsi721_omsg_handler(struct tsi721_device *priv, int ch);
static void tsi721_imsg_handler(struct tsi721_device *priv, int ch);
@@ -2840,6 +2844,16 @@ static int tsi721_probe(struct pci_dev *pdev,
pcie_capability_clear_and_set_word(pdev, PCI_EXP_DEVCTL,
PCI_EXP_DEVCTL_RELAX_EN | PCI_EXP_DEVCTL_NOSNOOP_EN, 0);
+ /* Override PCIe Maximum Read Request Size setting if requested */
+ if (pcie_mrrs >= 0) {
+ if (pcie_mrrs <= 5)
+ pcie_capability_clear_and_set_word(pdev, PCI_EXP_DEVCTL,
+ PCI_EXP_DEVCTL_READRQ, pcie_mrrs << 12);
+ else
+ tsi_info(&pdev->dev,
+ "Invalid MRRS override value %d", pcie_mrrs);
+ }
+
/* Adjust PCIe completion timeout. */
pcie_capability_clear_and_set_word(pdev, PCI_EXP_DEVCTL2, 0xf, 0x2);

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