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PCI: dwc: Strengthen the MSI address allocation logic

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There can be platforms that do not use/have 32-bit DMA addresses.
The current implementation of 32-bit IOVA allocation can fail for
such platforms, eventually leading to the probe failure.

Try to allocate a 32-bit msi_data. If this allocation fails,
attempt a 64-bit address allocation. Please note that if the
64-bit MSI address is allocated, then the EPs supporting 32-bit
MSI address only will not work.

Link: https://lore.kernel.org/linux-pci/20240221153840.1789979-1-ajayagarwal@google.com
Tested-by: Will McVicker <willmcvicker@google.com>
Signed-off-by: Ajay Agarwal <ajayagarwal@google.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Will McVicker <willmcvicker@google.com>
This commit is contained in:
Ajay Agarwal 2024-02-21 21:08:40 +05:30 committed by Krzysztof Wilczyński
parent 6613476e22
commit f3a296405b
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GPG Key ID: 7C64768D3DE334E7
1 changed files with 13 additions and 8 deletions
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13
drivers/pci/controller/dwc/pcie-designware-host.c
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@ -328,7 +328,7 @@ static int dw_pcie_msi_host_init(struct dw_pcie_rp *pp)
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
struct device *dev = pci->dev;
struct platform_device *pdev = to_platform_device(dev);
u64 *msi_vaddr;
u64 *msi_vaddr = NULL;
int ret;
u32 ctrl, num_ctrls;
@ -379,16 +379,21 @@ static int dw_pcie_msi_host_init(struct dw_pcie_rp *pp)
* memory.
*/
ret = dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
if (ret)
dev_warn(dev, "Failed to set DMA mask to 32-bit. Devices with only 32-bit MSI support may not work properly\n");
if (!ret)
msi_vaddr = dmam_alloc_coherent(dev, sizeof(u64), &pp->msi_data,
GFP_KERNEL);
if (!msi_vaddr) {
dev_warn(dev, "Failed to allocate 32-bit MSI address\n");
dma_set_coherent_mask(dev, DMA_BIT_MASK(64));
msi_vaddr = dmam_alloc_coherent(dev, sizeof(u64), &pp->msi_data,
GFP_KERNEL);
if (!msi_vaddr) {
dev_err(dev, "Failed to alloc and map MSI data\n");
dev_err(dev, "Failed to allocate MSI address\n");
dw_pcie_free_msi(pp);
return -ENOMEM;
}
}
return 0;
}