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From: Niklas Cassel <cassel@kernel.org>
To: "Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Manivannan Sadhasivam" <manivannan.sadhasivam@linaro.org>,
	"Rob Herring" <robh@kernel.org>,
	"Bjorn Helgaas" <bhelgaas@google.com>
Cc: Damien Le Moal <dlemoal@kernel.org>,
	Siddharth Vadapalli <s-vadapalli@ti.com>,
	Udit Kumar <u-kumar1@ti.com>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Niklas Cassel <cassel@kernel.org>,
	linux-pci@vger.kernel.org
Subject: [PATCH v3 5/6] PCI: keystone: Specify correct alignment requirement
Date: Mon, 13 Jan 2025 11:27:36 +0100	[thread overview]
Message-ID: <20250113102730.1700963-13-cassel@kernel.org> (raw)
In-Reply-To: <20250113102730.1700963-8-cassel@kernel.org>

The support for a specific iATU alignment was added in
commit 2a9a801620ef ("PCI: endpoint: Add support to specify alignment for
buffers allocated to BARs").

This commit specifically mentions both that the alignment by each DWC
based EP driver should match CX_ATU_MIN_REGION_SIZE, and that AM65x
specifically has a 64 KB alignment.

This also matches the CX_ATU_MIN_REGION_SIZE value specified by
"12.2.2.4.7 PCIe Subsystem Address Translation" in the AM65x TRM:
https://www.ti.com/lit/ug/spruid7e/spruid7e.pdf

This higher value, 1 MB, was obviously an ugly hack used to be able to
handle Resizable BARs which have a minimum size of 1 MB.

Now when we actually have support for Resizable BARs, let's configure the
iATU alignment requirement to the actual requirement.
(BARs described as Resizable will still get aligned to 1 MB.)

Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/pci/controller/dwc/pci-keystone.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
index fdc610ec7e5e..76a37368ae4f 100644
--- a/drivers/pci/controller/dwc/pci-keystone.c
+++ b/drivers/pci/controller/dwc/pci-keystone.c
@@ -970,7 +970,7 @@ static const struct pci_epc_features ks_pcie_am654_epc_features = {
 	.bar[BAR_3] = { .type = BAR_FIXED, .fixed_size = SZ_64K, },
 	.bar[BAR_4] = { .type = BAR_FIXED, .fixed_size = 256, },
 	.bar[BAR_5] = { .type = BAR_RESIZABLE, },
-	.align = SZ_1M,
+	.align = SZ_64K,
 };
 
 static const struct pci_epc_features*
-- 
2.47.1


  parent reply	other threads:[~2025-01-13 10:28 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-13 10:27 [PATCH v3 0/6] PCI: endpoint: Add support for resizable BARs Niklas Cassel
2025-01-13 10:27 ` [PATCH v3 1/6] PCI: endpoint: Add BAR type BAR_RESIZABLE Niklas Cassel
2025-01-19  5:14   ` Manivannan Sadhasivam
2025-01-13 10:27 ` [PATCH v3 2/6] PCI: dwc: ep: Move dw_pcie_ep_find_ext_capability() Niklas Cassel
2025-01-19  5:15   ` Manivannan Sadhasivam
2025-01-13 10:27 ` [PATCH v3 3/6] PCI: dwc: endpoint: Add support for BAR type BAR_RESIZABLE Niklas Cassel
2025-01-19  5:29   ` Manivannan Sadhasivam
2025-01-13 10:27 ` [PATCH v3 4/6] PCI: keystone: Describe resizable BARs as resizable BARs Niklas Cassel
2025-01-19  5:31   ` Manivannan Sadhasivam
2025-01-13 10:27 ` Niklas Cassel [this message]
2025-01-19  5:32   ` [PATCH v3 5/6] PCI: keystone: Specify correct alignment requirement Manivannan Sadhasivam
2025-01-13 10:27 ` [PATCH v3 6/6] PCI: dw-rockchip: Describe resizable BARs as resizable BARs Niklas Cassel
2025-01-19  5:33   ` Manivannan Sadhasivam
2025-01-19  5:08 ` [PATCH v3 0/6] PCI: endpoint: Add support for " Manivannan Sadhasivam

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