[PATCH 0/2] thunderbolt: Fix buffers allocation for device without DisplayPort adaptors

[PATCH 0/2] thunderbolt: Fix buffers allocation for device without DisplayPort adaptors

[Gil Fine]

For the case of device without DP adaptors, we calculate incorrectly the
buffers allocation. Here we fix the calculation for this case.
In addition, we add a KUnit test for this case.

Gil Fine (2):
  thunderbolt: Fix buffers allocation for device without DisplayPort
    adaptors
  thunderbolt: Add KUnit test for buffer allocation for device without
    DisplayPort adaptors

 drivers/thunderbolt/test.c   | 92 ++++++++++++++++++++++++++++++++++++
 drivers/thunderbolt/tunnel.c |  7 ++-
 2 files changed, 97 insertions(+), 2 deletions(-)

-- 
2.17.1

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[PATCH 1/2] thunderbolt: Fix buffers allocation for device without DisplayPort adaptors

[Gil Fine]

For the case of device without DP adaptors, we calculate incorrectly the
buffers allocation. Here we fix the calculation for this case.

Signed-off-by: Gil Fine <gil.fine@intel.com>
---
 drivers/thunderbolt/tunnel.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/thunderbolt/tunnel.c b/drivers/thunderbolt/tunnel.c
index 8ccd70920b6a..2c3cf7fc3357 100644
--- a/drivers/thunderbolt/tunnel.c
+++ b/drivers/thunderbolt/tunnel.c
@@ -102,8 +102,11 @@ static unsigned int tb_available_credits(const struct tb_port *port,
 		 * Maximum number of DP streams possible through the
 		 * lane adapter.
 		 */
-		ndp = (credits - (usb3 + pcie + spare)) /
-		      (sw->min_dp_aux_credits + sw->min_dp_main_credits);
+		if (sw->min_dp_aux_credits + sw->min_dp_main_credits)
+			ndp = (credits - (usb3 + pcie + spare)) /
+			      (sw->min_dp_aux_credits + sw->min_dp_main_credits);
+		else
+			ndp = 0;
 	} else {
 		ndp = 0;
 	}
-- 
2.17.1

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[PATCH 2/2] thunderbolt: Add KUnit test for buffer allocation for device without DisplayPort adaptors

[Gil Fine]

Here we add KUnit test to test the buffer allocation for device without DP adaptors.

Signed-off-by: Gil Fine <gil.fine@intel.com>
---
 drivers/thunderbolt/test.c | 92 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

diff --git a/drivers/thunderbolt/test.c b/drivers/thunderbolt/test.c
index 66b6e665e96f..99b30f2624fc 100644
--- a/drivers/thunderbolt/test.c
+++ b/drivers/thunderbolt/test.c
@@ -341,6 +341,47 @@ static struct tb_switch *alloc_dev_with_dpin(struct kunit *test,
 	return sw;
 }
 
+static struct tb_switch *alloc_dev_without_dp(struct kunit *test,
+					      struct tb_switch *parent,
+					      u64 route, bool bonded)
+{
+	struct tb_switch *sw;
+	int i;
+
+	sw = alloc_dev_default(test, parent, route, bonded);
+	if (!sw)
+		return NULL;
+	/*
+	 * Device with:
+	 * 2x USB4 Adapters (adapters 1,2 and 3,4),
+	 * 1x PCIe Upstream (adapter 9),
+	 * 1x PCIe Downstream (adapter 10),
+	 * 1x USB3 Upstream (adapter 16),
+	 * 1x USB3 Downstream (adapter 17)
+	 */
+	for (i = 5; i <= 8; i++)
+		sw->ports[i].disabled = true;
+
+	for (i = 11; i <= 14; i++)
+		sw->ports[i].disabled = true;
+
+	sw->ports[13].cap_adap = 0;
+	sw->ports[14].cap_adap = 0;
+
+	for (i = 18; i <= 19; i++)
+		sw->ports[i].disabled = true;
+
+	sw->generation = 4;
+	sw->credit_allocation = true;
+	sw->max_usb3_credits = 109;
+	sw->min_dp_aux_credits = 0;
+	sw->min_dp_main_credits = 0;
+	sw->max_pcie_credits = 30;
+	sw->max_dma_credits = 1;
+
+	return sw;
+}
+
 static struct tb_switch *alloc_dev_usb4(struct kunit *test,
 					struct tb_switch *parent,
 					u64 route, bool bonded)
@@ -1996,6 +2037,56 @@ static void tb_test_credit_alloc_pcie(struct kunit *test)
 	tb_tunnel_free(tunnel);
 }
 
+static void tb_test_credit_alloc_without_dp(struct kunit *test)
+{
+	struct tb_switch *host, *dev;
+	struct tb_port *up, *down;
+	struct tb_tunnel *tunnel;
+	struct tb_path *path;
+
+	host = alloc_host_usb4(test);
+	dev = alloc_dev_without_dp(test, host, 0x1, true);
+
+	/*
+	 * The device has no DP therefore baMinDPmain = baMinDPaux = 0
+	 *
+	 * Create PCIe path with buffers less than baMaxPCIe.
+	 *
+	 * For a device with buffers configurations:
+	 * baMaxUSB3 = 109
+	 * baMinDPaux = 0
+	 * baMinDPmain = 0
+	 * baMaxPCIe = 30
+	 * baMaxHI = 1
+	 * Remaining Buffers = Total - (CP + DP) = 120 - (2 + 0) = 118
+	 * PCIe Credits = Max(6, Min(baMaxPCIe, Remaining Buffers - baMaxUSB3)
+	 *		= Max(6, Min(30, 9) = 9
+	 */
+	down = &host->ports[8];
+	up = &dev->ports[9];
+	tunnel = tb_tunnel_alloc_pci(NULL, up, down);
+	KUNIT_ASSERT_TRUE(test, tunnel != NULL);
+	KUNIT_ASSERT_EQ(test, tunnel->npaths, (size_t)2);
+
+	/* PCIe downstream path */
+	path = tunnel->paths[0];
+	KUNIT_ASSERT_EQ(test, path->path_length, 2);
+	KUNIT_EXPECT_EQ(test, path->hops[0].nfc_credits, 0U);
+	KUNIT_EXPECT_EQ(test, path->hops[0].initial_credits, 7U);
+	KUNIT_EXPECT_EQ(test, path->hops[1].nfc_credits, 0U);
+	KUNIT_EXPECT_EQ(test, path->hops[1].initial_credits, 9U);
+
+	/* PCIe upstream path */
+	path = tunnel->paths[1];
+	KUNIT_ASSERT_EQ(test, path->path_length, 2);
+	KUNIT_EXPECT_EQ(test, path->hops[0].nfc_credits, 0U);
+	KUNIT_EXPECT_EQ(test, path->hops[0].initial_credits, 7U);
+	KUNIT_EXPECT_EQ(test, path->hops[1].nfc_credits, 0U);
+	KUNIT_EXPECT_EQ(test, path->hops[1].initial_credits, 64U);
+
+	tb_tunnel_free(tunnel);
+}
+
 static void tb_test_credit_alloc_dp(struct kunit *test)
 {
 	struct tb_switch *host, *dev;
@@ -2709,6 +2800,7 @@ static struct kunit_case tb_test_cases[] = {
 	KUNIT_CASE(tb_test_credit_alloc_legacy_not_bonded),
 	KUNIT_CASE(tb_test_credit_alloc_legacy_bonded),
 	KUNIT_CASE(tb_test_credit_alloc_pcie),
+	KUNIT_CASE(tb_test_credit_alloc_without_dp),
 	KUNIT_CASE(tb_test_credit_alloc_dp),
 	KUNIT_CASE(tb_test_credit_alloc_usb3),
 	KUNIT_CASE(tb_test_credit_alloc_dma),
-- 
2.17.1

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Re: [PATCH 0/2] thunderbolt: Fix buffers allocation for device without DisplayPort adaptors

[Mika Westerberg]

Hi Gil,

On Mon, May 09, 2022 at 11:49:02PM +0300, Gil Fine wrote:
> For the case of device without DP adaptors, we calculate incorrectly the
> buffers allocation. Here we fix the calculation for this case.
> In addition, we add a KUnit test for this case.
> 
> Gil Fine (2):
>   thunderbolt: Fix buffers allocation for device without DisplayPort
>     adaptors
>   thunderbolt: Add KUnit test for buffer allocation for device without
>     DisplayPort adaptors

Both applied to thunderbolt.git/next, thanks!