Pali Rohár 1fd54253bc arm: a37xx: pci: Fix a3700_fdt_fix_pcie_regions() function again ... The a3700_fdt_fix_pcie_regions() function still computes nonsense. It computes the fixup offset from the PCI address taken from the first row of the "ranges" array, which means that: - PCI address must equal CPU address (otherwise the computed fix offset will be wrong), - the first row must contain the lowest address. This is the case for the default device-tree, which is why we didn't notice it. It also adds the fixup offset to all PCI and CPU addresses, which is wrong. Instead: 1) The fixup offset must be computed from the CPU address, not PCI address. 2) The fixup offset must be computed from the row containing the lowest CPU address, which is not necessarily contained in the first row. 3) The PCI address - the address to which the PCIe controller remaps the address space as seen from the point of view of the PCIe device - must be fixed by the fix offset in the same way as the CPU address only in the special case when the CPU adn PCI addresses are the same. Same addresses means that remapping is disabled, and thus if we change the CPU address, we need also to change the PCI address so that the remapping is still disabled afterwards. Consider an example: The ranges entries contain: PCI address CPU address 70000000 EA000000 E9000000 E9000000 EB000000 EB000000 By default CPU PCIe window is at: E8000000 - F0000000 Consider the case when TF-A moves it to: F2000000 - FA000000 Until now the function would take the PCI address of the first entry: 70000000, and the new base, F2000000, to compute the fix offset: F2000000 - 70000000 = 82000000, and then add 8200000 to all addresses, resulting in PCI address CPU address F2000000 6C000000 6B000000 6B000000 6D000000 6D000000 which is complete nonsense - none of the CPU addresses is in the requested window. Now it will take the lowest CPU address, which is in second row, E9000000, and compute the fix offset F2000000 - E9000000 = 09000000, and then add it to all CPU addresses and those PCI addresses which equal to their corresponding CPU addresses, resulting in PCI address CPU address 70000000 F3000000 F2000000 F2000000 F4000000 F4000000 where all of the CPU addresses are in the needed window. Fixes: 4a82fca8e3 ("arm: a37xx: pci: Fix a3700_fdt_fix_pcie_regions() function") Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Marek Behún <marek.behun@nic.cz> Reviewed-by: Stefan Roese <sr@denx.de>		2022-03-04 08:38:05 +01:00
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cpu.c	arm: a37xx: pci: Fix a3700_fdt_fix_pcie_regions() function again	2022-03-04 08:38:05 +01:00
Makefile	SPDX: Convert all of our single license tags to Linux Kernel style	2018-05-07 09:34:12 -04:00