[bug report] ASoC: Intel: mrfld - create separate module for pci part

[Andy Shevchenko]

On Fri, Dec 03, 2021 at 07:46:04AM -0600, Pierre-Louis Bossart wrote:
> On 12/3/21 4:13 AM, Dan Carpenter wrote:
> > Hello Vinod Koul,
> > 
> > The patch f533a035e4da: "ASoC: Intel: mrfld - create separate module
> > for pci part" from Nov 4, 2014, leads to the following Smatch static
> > checker warning:
> > 
> > 	sound/soc/intel/atom/sst/sst_pci.c:102 sst_platform_get_resources()
> > 	warn: resource freed on success: 'ctx->pci'
> > 
> > sound/soc/intel/atom/sst/sst_pci.c
> >     25 static int sst_platform_get_resources(struct intel_sst_drv *ctx)
> >     26 {
> >     27         int ddr_base, ret = 0;
> >     28         struct pci_dev *pci = ctx->pci;
> >     29 
> >     30         ret = pci_request_regions(pci, SST_DRV_NAME);
> >     31         if (ret)
> >     32                 return ret;
> >     33 
> >     34         /* map registers */
> >     35         /* DDR base */
> >     36         if (ctx->dev_id == SST_MRFLD_PCI_ID) {
> >     37                 ctx->ddr_base = pci_resource_start(pci, 0);
> >     38                 /* check that the relocated IMR base matches with FW Binary */
> >     39                 ddr_base = relocate_imr_addr_mrfld(ctx->ddr_base);
> >     40                 if (!ctx->pdata->lib_info) {
> >     41                         dev_err(ctx->dev, "lib_info pointer NULL\n");
> >     42                         ret = -EINVAL;
> >     43                         goto do_release_regions;
> >     44                 }
> >     45                 if (ddr_base != ctx->pdata->lib_info->mod_base) {
> >     46                         dev_err(ctx->dev,
> >     47                                         "FW LSP DDR BASE does not match with IFWI\n");
> >     48                         ret = -EINVAL;
> >     49                         goto do_release_regions;
> >     50                 }
> >     51                 ctx->ddr_end = pci_resource_end(pci, 0);
> >     52 
> >     53                 ctx->ddr = pcim_iomap(pci, 0,
> >     54                                         pci_resource_len(pci, 0));
> >     55                 if (!ctx->ddr) {
> >     56                         ret = -EINVAL;
> >     57                         goto do_release_regions;
> >     58                 }
> >     59                 dev_dbg(ctx->dev, "sst: DDR Ptr %p\n", ctx->ddr);
> >     60         } else {
> >     61                 ctx->ddr = NULL;
> >     62         }
> >     63         /* SHIM */
> >     64         ctx->shim_phy_add = pci_resource_start(pci, 1);
> >     65         ctx->shim = pcim_iomap(pci, 1, pci_resource_len(pci, 1));
> >     66         if (!ctx->shim) {
> >     67                 ret = -EINVAL;
> >     68                 goto do_release_regions;
> >     69         }
> >     70         dev_dbg(ctx->dev, "SST Shim Ptr %p\n", ctx->shim);
> >     71 
> >     72         /* Shared SRAM */
> >     73         ctx->mailbox_add = pci_resource_start(pci, 2);
> >     74         ctx->mailbox = pcim_iomap(pci, 2, pci_resource_len(pci, 2));
> >     75         if (!ctx->mailbox) {
> >     76                 ret = -EINVAL;
> >     77                 goto do_release_regions;
> >     78         }
> >     79         dev_dbg(ctx->dev, "SRAM Ptr %p\n", ctx->mailbox);
> >     80 
> >     81         /* IRAM */
> >     82         ctx->iram_end = pci_resource_end(pci, 3);
> >     83         ctx->iram_base = pci_resource_start(pci, 3);
> >     84         ctx->iram = pcim_iomap(pci, 3, pci_resource_len(pci, 3));
> >     85         if (!ctx->iram) {
> >     86                 ret = -EINVAL;
> >     87                 goto do_release_regions;
> >     88         }
> >     89         dev_dbg(ctx->dev, "IRAM Ptr %p\n", ctx->iram);
> >     90 
> >     91         /* DRAM */
> >     92         ctx->dram_end = pci_resource_end(pci, 4);
> >     93         ctx->dram_base = pci_resource_start(pci, 4);
> >     94         ctx->dram = pcim_iomap(pci, 4, pci_resource_len(pci, 4));
> >     95         if (!ctx->dram) {
> >     96                 ret = -EINVAL;
> >     97                 goto do_release_regions;
> >     98         }
> >     99         dev_dbg(ctx->dev, "DRAM Ptr %p\n", ctx->dram);
> >     100 do_release_regions:
> >     101         pci_release_regions(pci);
> > --> 102         return ret;
> >     103 }
> > 
> > Surely there should be a "return 0;" before the do_release_regions:
> > label?  How does this code work?
> 
> Thanks for reporting this Dan. Yes this doesn't look good at all.
> 
> This PCI part is only used on Merrifield/Tangier, and I am not sure if
> anyone ever managed to make audio work with the upstream version of this
> driver. It's my understanding that this platform is no longer maintained
> by Intel, and the Edison Yocto code uses the SOF driver.
> 
> The Kconfig updated in 2018 hints at those limitations:
> 
> config SND_SST_ATOM_HIFI2_PLATFORM_PCI
> 	tristate "PCI HiFi2 (Merrifield) Platforms"
> 	depends on X86 && PCI
> 	select SND_SST_ATOM_HIFI2_PLATFORM
> 	help
> 	  If you have a Intel Merrifield/Edison platform, then
> 	  enable this option by saying Y or m. Distros will typically not
> 	  enable this option: while Merrifield/Edison can run a mainline
> 	  kernel with limited functionality it will require a firmware file
> 	  which is not in the standard firmware tree
> 
> I would guess that indeed a return 0; is missing, but maybe it's time to
> remove this PCI code completely. I can't think of any user of the PCI
> parts of this driver.
> 
> Andy, Hans, Mark, Takashi, what do you think?

The Edison platform and actually some more based on Intel Merrifield are still
alive and on the (second hand) market. But yes, I would rather focus on making
SOF working there, but via PCI bus (or with ACPI, ASL code for which one should
actually write down, currently it's a device with PCI interface only).

-- 
With Best Regards,
Andy Shevchenko