On Mon, Jul 08, 2024 at 01:26:30PM -0700, Eric Biggers wrote: > Hi Peter, > > On Thu, Jul 04, 2024 at 02:26:05PM +0100, Peter Griffin wrote: > > Do you know how these FMP registers (FMPSECURITY0 etc) relate to the > > UFSPR* registers set in the existing exynos_ufs_config_smu()? The > > UFS_LINK spec talks about UFSPR(FMP), so I had assumed the FMP support > > would be writing these same registers but via SMC call. > > > > I think by the looks of things > > > > #define UFSPRSECURITY 0x010 > > #define UFSPSBEGIN0 0x200 > > #define UFSPSEND0 0x204 > > #define UFSPSLUN0 0x208 > > #define UFSPSCTRL0 0x20C > > > > relates to the following registers in gs101 spec > > > > FMPSECURITY0 0x0010 > > FMPSBEGIN0 0x2000 > > FMPSEND0 0x2004 > > FMPSLUN0 0x2008 > > FMPSCTRL0 0x200C > > > > And the SMC calls your calling set those same registers as > > exynos_ufs_config_smu() function. Although it is hard to be certain as > > I don't have access to the firmware code. Certainly the comment below > > about FMPSECURITY0 implies that :) > > > > With that in mind I think exynos_ufs_fmp_init() function in this patch > > needs to be better integrated with the EXYNOS_UFS_OPT_UFSPR_SECURE > > flag and the existing exynos_ufs_config_smu() function that is > > currently just disabling decryption on platforms where it can access > > the UFSPR(FMP) regs via mmio. > > I think that is all correct. For some reason, on gs101 the FMP registers are > not accessible by the "normal world", and SMC calls need to be used instead. > The sequences of SMC calls originated from Samsung's Linux driver code for FMP. > So I know they are the magic incantations that are needed, but I don't have > access to the source code or documentation for them. It does seem clear that > one of the things they must do is write the needed values to the FMP registers. > > I'd hope that these same SMC calls also work on Exynos-based SoCs that do make > the FMP registers accessible to the "normal world", and therefore they can just > be used on all Exynos-based SoCs and ufs-exynos won't need two different code > paths. But I don't have a way to confirm this myself. Until someone is able to > confirm this, I think we need to make the FMP support depend on > EXYNOS_UFS_OPT_UFSPR_SECURE so that it doesn't conflict with > exynos_ufs_config_smu() which runs when !EXYNOS_UFS_OPT_UFSPR_SECURE. > These same SMC calls can be found in the downstream source for other Exynos-based SoCs. I suspect that exynos_ufs_config_smu() should be removed, and exynos_ufs_fmp_init() should run regardless of EXYNOS_UFS_OPT_UFSPR_SECURE. It still would need to be tested, though, which I'm not able to do. (And especially as a cryptography feature, this *must* be tested...) So for now I'm going to make the FMP support conditional on EXYNOS_UFS_OPT_UFSPR_SECURE. - Eric
