Re: [PATCH V3 10/16] platform/x86/intel/pmc: Split pmc_core_ssram_get_pmc()

[Ilpo Järvinen]

On Wed, 11 Oct 2023, David E. Box wrote:

> On supported hardware, each PMC may have an associated SSRAM device for
> accessing additional counters.  However, only the SSRAM of the first
> (primary) PMC is discoverable as a PCI device to the OS. The remaining
> (secondary) devices are hidden but their BARs are still accessible and
> their addresses are stored in the BAR of the exposed device. Clean up the
> code handling the SSRAM discovery. Create two separate functions for
> accessing the primary and secondary SSRAM devices.
> 
> Signed-off-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
> ---
> V3 - New patch split from previous PATCH 2
>    - Update changelog
>    - Use cleanup.h to cleanup ioremap
> 
> V2 - no change
> 
>  drivers/platform/x86/intel/pmc/core_ssram.c | 93 ++++++++++++++-------
>  1 file changed, 61 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel/pmc/core_ssram.c b/drivers/platform/x86/intel/pmc/core_ssram.c
> index 815950713e25..af405d11919f 100644
> --- a/drivers/platform/x86/intel/pmc/core_ssram.c
> +++ b/drivers/platform/x86/intel/pmc/core_ssram.c
> @@ -8,6 +8,7 @@
>   *
>   */
>  
> +#include <linux/cleanup.h>
>  #include <linux/pci.h>
>  #include <linux/io-64-nonatomic-lo-hi.h>
>  
> @@ -21,6 +22,8 @@
>  #define SSRAM_IOE_OFFSET	0x68
>  #define SSRAM_DEVID_OFFSET	0x70
>  
> +DEFINE_FREE(pmc_core_iounmap, void __iomem *, iounmap(_T));
> +

Was it that adding

DEFINE_FREE(iounmap, void __iomem *, iounmap(_T));

into some header did not work for some reason or why this? (Perhaps 
because iounmap is also defined?)

-- 
 i.

>  static const struct pmc_reg_map *pmc_core_find_regmap(struct pmc_info *list, u16 devid)
>  {
>  	for (; list->map; ++list)
> @@ -65,44 +68,74 @@ pmc_core_pmc_add(struct pmc_dev *pmcdev, u64 pwrm_base,
>  	return 0;
>  }
>  
> -static void
> -pmc_core_ssram_get_pmc(struct pmc_dev *pmcdev, void __iomem *ssram, u32 offset,
> -		       int pmc_idx)
> +static int
> +pmc_core_get_secondary_pmc(struct pmc_dev *pmcdev, int pmc_idx, u32 offset)
>  {
> -	u64 pwrm_base;
> +	struct pci_dev *ssram_pcidev = pmcdev->ssram_pcidev;
> +	void __iomem __free(pmc_core_iounmap) *main_ssram = NULL;
> +	void __iomem __free(pmc_core_iounmap) *secondary_ssram = NULL;
> +	const struct pmc_reg_map *map;
> +	u64 ssram_base, pwrm_base;
>  	u16 devid;
>  
> -	if (pmc_idx != PMC_IDX_SOC) {
> -		u64 ssram_base = get_base(ssram, offset);
> +	if (!pmcdev->regmap_list)
> +		return -ENOENT;
>  
> -		if (!ssram_base)
> -			return;
> +	/*
> +	 * The secondary PMC BARS (which are behind hidden PCI devices) are read
> +	 * from fixed offsets in MMIO of the primary PMC BAR.
> +	 */
> +	ssram_base = ssram_pcidev->resource[0].start;
> +	main_ssram = ioremap(ssram_base, SSRAM_HDR_SIZE);
> +	if (!main_ssram)
> +		return -ENOMEM;
>  
> -		ssram = ioremap(ssram_base, SSRAM_HDR_SIZE);
> -		if (!ssram)
> -			return;
> -	}
> +	ssram_base = get_base(main_ssram, offset);
> +	secondary_ssram = ioremap(ssram_base, SSRAM_HDR_SIZE);
> +	if (!secondary_ssram)
> +		return -ENOMEM;
> +
> +	pwrm_base = get_base(secondary_ssram, SSRAM_PWRM_OFFSET);
> +	devid = readw(secondary_ssram + SSRAM_DEVID_OFFSET);
> +
> +	map = pmc_core_find_regmap(pmcdev->regmap_list, devid);
> +	if (!map)
> +		return -ENODEV;
> +
> +	return pmc_core_pmc_add(pmcdev, pwrm_base, map, pmc_idx);
> +}
> +
> +static int
> +pmc_core_get_primary_pmc(struct pmc_dev *pmcdev)
> +{
> +	struct pci_dev *ssram_pcidev = pmcdev->ssram_pcidev;
> +	void __iomem __free(pmc_core_iounmap) *ssram;
> +	const struct pmc_reg_map *map;
> +	u64 ssram_base, pwrm_base;
> +	u16 devid;
> +
> +	if (!pmcdev->regmap_list)
> +		return -ENOENT;
> +
> +	/* The primary PMC (SOC die) BAR is BAR 0 in config space. */
> +	ssram_base = ssram_pcidev->resource[0].start;
> +	ssram = ioremap(ssram_base, SSRAM_HDR_SIZE);
> +	if (!ssram)
> +		return -ENOMEM;
>  
>  	pwrm_base = get_base(ssram, SSRAM_PWRM_OFFSET);
>  	devid = readw(ssram + SSRAM_DEVID_OFFSET);
>  
> -	if (pmcdev->regmap_list) {
> -		const struct pmc_reg_map *map;
> +	map = pmc_core_find_regmap(pmcdev->regmap_list, devid);
> +	if (!map)
> +		return -ENODEV;
>  
> -		map = pmc_core_find_regmap(pmcdev->regmap_list, devid);
> -		if (map)
> -			pmc_core_pmc_add(pmcdev, pwrm_base, map, pmc_idx);
> -	}
> -
> -	if (pmc_idx != PMC_IDX_SOC)
> -		iounmap(ssram);
> +	return pmc_core_pmc_add(pmcdev, pwrm_base, map, PMC_IDX_MAIN);
>  }
>  
>  int pmc_core_ssram_init(struct pmc_dev *pmcdev)
>  {
> -	void __iomem *ssram;
>  	struct pci_dev *pcidev;
> -	u64 ssram_base;
>  	int ret;
>  
>  	pcidev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(20, 2));
> @@ -113,18 +146,14 @@ int pmc_core_ssram_init(struct pmc_dev *pmcdev)
>  	if (ret)
>  		goto release_dev;
>  
> -	ssram_base = pcidev->resource[0].start;
> -	ssram = ioremap(ssram_base, SSRAM_HDR_SIZE);
> -	if (!ssram)
> -		goto disable_dev;
> -
>  	pmcdev->ssram_pcidev = pcidev;
>  
> -	pmc_core_ssram_get_pmc(pmcdev, ssram, 0, PMC_IDX_SOC);
> -	pmc_core_ssram_get_pmc(pmcdev, ssram, SSRAM_IOE_OFFSET, PMC_IDX_IOE);
> -	pmc_core_ssram_get_pmc(pmcdev, ssram, SSRAM_PCH_OFFSET, PMC_IDX_PCH);
> +	ret = pmc_core_get_primary_pmc(pmcdev);
> +	if (ret)
> +		goto disable_dev;
>  
> -	iounmap(ssram);
> +	pmc_core_get_secondary_pmc(pmcdev, PMC_IDX_IOE, SSRAM_IOE_OFFSET);
> +	pmc_core_get_secondary_pmc(pmcdev, PMC_IDX_PCH, SSRAM_PCH_OFFSET);
>  
>  	return 0;
>  
>