| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20250911215048.GA1591374@bhelgaas>
Date: Thu, 11 Sep 2025 16:50:48 -0500
From: Bjorn Helgaas <helgaas@...nel.org>
To: Devendra K Verma <devendra.verma@....com>
Cc: bhelgaas@...gle.com, mani@...nel.org, vkoul@...nel.org,
dmaengine@...r.kernel.org, linux-pci@...r.kernel.org,
linux-kernel@...r.kernel.org, michal.simek@....com
Subject: Re: [PATCH v1 1/2] dmaengine: dw-edma: Add AMD MDB Endpoint Support
On Thu, Sep 11, 2025 at 05:14:50PM +0530, Devendra K Verma wrote:
> AMD MDB PCIe endpoint support. For AMD specific support
> added the following
> - AMD supported PCIe Device IDs and Vendor ID (Xilinx).
> - AMD MDB specific driver data
> - AMD MDB specific VSEC capability to retrieve the device DDR
> base address.
>
> Signed-off-by: Devendra K Verma <devendra.verma@....com>
> ---
> Changes in v1:
> Removed the pci device id from pci_ids.h file.
> Added the vendor id macro as per the suggested method.
> Changed the type of the newly added devmem_phys_off variable.
> Added to logic to assign offsets for LL and data region blocks
> in case more number of channels are enabled than given in
> amd_mdb_data struct.
> ---
> drivers/dma/dw-edma/dw-edma-pcie.c | 132 ++++++++++++++++++++++++++++++++++++-
> 1 file changed, 131 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
> index 3371e0a7..48ecfce 100644
> --- a/drivers/dma/dw-edma/dw-edma-pcie.c
> +++ b/drivers/dma/dw-edma/dw-edma-pcie.c
> @@ -23,6 +23,11 @@
> #define DW_PCIE_VSEC_DMA_WR_CH GENMASK(9, 0)
> #define DW_PCIE_VSEC_DMA_RD_CH GENMASK(25, 16)
>
> +/* AMD MDB specific defines */
> +#define DW_PCIE_XILINX_MDB_VSEC_ID 0x20
> +#define PCI_DEVICE_ID_AMD_MDB_B054 0xb054
> +#define DW_PCIE_AMD_MDB_INVALID_ADDR (~0ULL)
> +
> #define DW_BLOCK(a, b, c) \
> { \
> .bar = a, \
> @@ -50,6 +55,7 @@ struct dw_edma_pcie_data {
> u8 irqs;
> u16 wr_ch_cnt;
> u16 rd_ch_cnt;
> + pci_bus_addr_t devmem_phys_off;
Based on your previous response, I don't think pci_bus_addr_t is the
right type. IIUC devmem_phys_off is not an address that a PCIe
analyzer would ever see in a TLP. It sounds like it's the result of
applying an iATU translation to a PCI bus address.
I'm not sure there's a special type for that, so u64 might be as good
as anything.
> };
>
> static const struct dw_edma_pcie_data snps_edda_data = {
> @@ -90,6 +96,89 @@ struct dw_edma_pcie_data {
> .rd_ch_cnt = 2,
> };
>
> +static const struct dw_edma_pcie_data amd_mdb_data = {
> + /* MDB registers location */
> + .rg.bar = BAR_0,
> + .rg.off = 0x00001000, /* 4 Kbytes */
> + .rg.sz = 0x00002000, /* 8 Kbytes */
> + /* MDB memory linked list location */
> + .ll_wr = {
> + /* Channel 0 - BAR 2, offset 0 Mbytes, size 2 Kbytes */
> + DW_BLOCK(BAR_2, 0x00000000, 0x00000800)
> + /* Channel 1 - BAR 2, offset 2 Mbytes, size 2 Kbytes */
> + DW_BLOCK(BAR_2, 0x00200000, 0x00000800)
> + },
> + .ll_rd = {
> + /* Channel 0 - BAR 2, offset 4 Mbytes, size 2 Kbytes */
> + DW_BLOCK(BAR_2, 0x00400000, 0x00000800)
> + /* Channel 1 - BAR 2, offset 6 Mbytes, size 2 Kbytes */
> + DW_BLOCK(BAR_2, 0x00600000, 0x00000800)
> + },
> + /* MDB memory data location */
> + .dt_wr = {
> + /* Channel 0 - BAR 2, offset 8 Mbytes, size 2 Kbytes */
> + DW_BLOCK(BAR_2, 0x00800000, 0x00000800)
> + /* Channel 1 - BAR 2, offset 9 Mbytes, size 2 Kbytes */
> + DW_BLOCK(BAR_2, 0x00900000, 0x00000800)
> + },
> + .dt_rd = {
> + /* Channel 0 - BAR 2, offset 10 Mbytes, size 2 Kbytes */
> + DW_BLOCK(BAR_2, 0x00a00000, 0x00000800)
> + /* Channel 1 - BAR 2, offset 11 Mbytes, size 2 Kbytes */
> + DW_BLOCK(BAR_2, 0x00b00000, 0x00000800)
> + },
> + /* Other */
> + .mf = EDMA_MF_HDMA_NATIVE,
> + .irqs = 1,
> + .wr_ch_cnt = 2,
> + .rd_ch_cnt = 2,
> +};
> +
> +static void dw_edma_assign_chan_data(struct dw_edma_pcie_data *pdata,
> + enum pci_barno bar)
> +{
> + u16 i;
> + off_t off = 0, offsz = 0x200000;
> + size_t size = 0x800;
> + u16 wr_ch = pdata->wr_ch_cnt;
> + u16 rd_ch = pdata->rd_ch_cnt;
> +
> + if (wr_ch <= 2 || rd_ch <= 2)
> + return;
> +
> + /* Write channel LL region */
> + for (i = 0; i < wr_ch; i++) {
> + pdata->ll_wr[i].bar = bar;
> + pdata->ll_wr[i].off = off;
> + pdata->ll_wr[i].sz = size;
> + off += offsz + size;
> + }
> +
> + /* Read channel LL region */
> + for (i = 0; i < rd_ch; i++) {
> + pdata->ll_rd[i].bar = bar;
> + pdata->ll_rd[i].off = off;
> + pdata->ll_rd[i].sz = size;
> + off += offsz + size;
> + }
> +
> + /* Write channel data region */
> + for (i = 0; i < wr_ch; i++) {
> + pdata->dt_wr[i].bar = bar;
> + pdata->dt_wr[i].off = off;
> + pdata->dt_wr[i].sz = size;
> + off += offsz + size;
> + }
> +
> + /* Read channel data region */
> + for (i = 0; i < rd_ch; i++) {
> + pdata->dt_rd[i].bar = bar;
> + pdata->dt_rd[i].off = off;
> + pdata->dt_rd[i].sz = size;
> + off += offsz + size;
> + }
> +}
> +
> static int dw_edma_pcie_irq_vector(struct device *dev, unsigned int nr)
> {
> return pci_irq_vector(to_pci_dev(dev), nr);
> @@ -121,7 +210,11 @@ static void dw_edma_pcie_get_vsec_dma_data(struct pci_dev *pdev,
> u16 vsec;
> u64 off;
>
> - vsec = pci_find_vsec_capability(pdev, PCI_VENDOR_ID_SYNOPSYS,
> + /*
> + * Synopsys and AMD (Xilinx) use the same VSEC ID for the purpose
> + * of map, channel counts, etc.
> + */
> + vsec = pci_find_vsec_capability(pdev, pdev->vendor,
> DW_PCIE_VSEC_DMA_ID);
You must validate pdev->vendor first. Passing pdev->vendor means this
will find any VSEC with ID 0x6 on any device at all. For example, you
could find a VSEC with ID 0x6 on an Intel device where VSEC ID 0x6
means something completely different.
You have to know what the Vendor ID is before calling
pci_find_vsec_capability() because otherwise you don't know what the
VSEC ID means.
The best way to do this would be to use a separate #define for each
vendor to remove the assumption that each vendor uses the same ID:
#define DW_PCIE_SYNOPSYS_VSEC_DMA_ID 0x6
#define DW_PCIE_XILINX_VSEC_DMA_ID 0x6
vsec = pci_find_vsec_capability(pdev, PCI_VENDOR_ID_SYNOPSYS,
DW_PCIE_SYNOPSYS_VSEC_DMA_ID);
if (!vsec) {
vsec = pci_find_vsec_capability(pdev, PCI_VENDOR_ID_XILINX,
DW_PCIE_XILINX_VSEC_DMA_ID);
if (!vsec)
return;
}
That way it's clear that this only applies to Synopsys devices and
Xilinx devices, Synopsys and Xilinx implemented a VSEC with the same
semantics, and it's just a coincidence that they assigned the same
VSEC ID.
> if (!vsec)
> return;
> @@ -155,6 +248,24 @@ static void dw_edma_pcie_get_vsec_dma_data(struct pci_dev *pdev,
> off <<= 32;
> off |= val;
> pdata->rg.off = off;
> +
> + /* AMD specific VSEC capability */
> + vsec = pci_find_vsec_capability(pdev, pdev->vendor,
> + DW_PCIE_XILINX_MDB_VSEC_ID);
Same here. This will find a VSEC with ID 0x20 on any device from any
vendor at all. But you only know what 0x20 means on Xilinx devices,
so this should be:
vsec = pci_find_vsec_capability(pdev, PCI_VENDOR_ID_XILINX,
DW_PCIE_XILINX_MDB_VSEC_ID);
> + if (!vsec)
> + return;
> +
> + pci_read_config_dword(pdev, vsec + PCI_VNDR_HEADER, &val);
> + if (PCI_VNDR_HEADER_ID(val) != 0x20 ||
> + PCI_VNDR_HEADER_REV(val) != 0x1)
> + return;
> +
> + pci_read_config_dword(pdev, vsec + 0xc, &val);
> + off = val;
> + pci_read_config_dword(pdev, vsec + 0x8, &val);
> + off <<= 32;
> + off |= val;
> + pdata->devmem_phys_off = off;
> }
>
> static int dw_edma_pcie_probe(struct pci_dev *pdev,
> @@ -179,6 +290,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
> }
>
> memcpy(vsec_data, pdata, sizeof(struct dw_edma_pcie_data));
> + vsec_data->devmem_phys_off = DW_PCIE_AMD_MDB_INVALID_ADDR;
>
> /*
> * Tries to find if exists a PCIe Vendor-Specific Extended Capability
> @@ -186,6 +298,22 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
> */
> dw_edma_pcie_get_vsec_dma_data(pdev, vsec_data);
>
> + if (pdev->vendor == PCI_VENDOR_ID_XILINX) {
> + /*
> + * There is no valid address found for the LL memory
> + * space on the device side.
> + */
> + if (vsec_data->devmem_phys_off == DW_PCIE_AMD_MDB_INVALID_ADDR)
> + return -EINVAL;
> +
> + /*
> + * Configure the channel LL and data blocks if number of
> + * channels enabled in VSEC capability are more than the
> + * channels configured in amd_mdb_data.
> + */
> + dw_edma_assign_chan_data(vsec_data, BAR_2);
> + }
> +
> /* Mapping PCI BAR regions */
> mask = BIT(vsec_data->rg.bar);
> for (i = 0; i < vsec_data->wr_ch_cnt; i++) {
> @@ -367,6 +495,8 @@ static void dw_edma_pcie_remove(struct pci_dev *pdev)
>
> static const struct pci_device_id dw_edma_pcie_id_table[] = {
> { PCI_DEVICE_DATA(SYNOPSYS, EDDA, &snps_edda_data) },
> + { PCI_VDEVICE(XILINX, PCI_DEVICE_ID_AMD_MDB_B054),
> + (kernel_ulong_t)&amd_mdb_data },
> { }
> };
> MODULE_DEVICE_TABLE(pci, dw_edma_pcie_id_table);
> --
> 1.8.3.1
>
Powered by blists - more mailing lists