Re: [Intel-gfx] [PATCH] drm/i915/dmc: Add MMIO range restrictions

["Srivatsa, Anusha" <anusha.srivatsa@intel.com>]

> -----Original Message-----
> From: De Marchi, Lucas <lucas.demarchi@intel.com>
> Sent: Tuesday, May 3, 2022 5:31 PM
> To: Srivatsa, Anusha <anusha.srivatsa@intel.com>
> Cc: intel-gfx@lists.freedesktop.org; stable@vger.kernel.org
> Subject: Re: [PATCH] drm/i915/dmc: Add MMIO range restrictions
> 
> On Tue, May 03, 2022 at 05:13:46PM -0700, Anusha Srivatsa wrote:
> >Bspec has added some steps that check forDMC MMIO range before
> >programming them
> >
> >v2: Fix for CI
> >v3: move register defines to .h (Anusha)
> >- Check MMIO restrictions per pipe
> >- Add MMIO restricton for v1 dmc header as well (Lucas)
> >v4: s/_PICK/_PICK_EVEN and use it only for Pipe DMC scenario.
> >- clean up sanity check logic.(Lucas)
> >- Add MMIO range for RKL as well.(Anusha)
> >
> >BSpec: 49193
> >
> >Cc: <stable@vger.kernel.org>
> >Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> >Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
> >---
> > drivers/gpu/drm/i915/display/intel_dmc.c      | 43 +++++++++++++++++++
> > drivers/gpu/drm/i915/display/intel_dmc_regs.h | 18 +++++++-
> > 2 files changed, 60 insertions(+), 1 deletion(-)
> >
> >diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c
> >b/drivers/gpu/drm/i915/display/intel_dmc.c
> >index 257cf662f9f4..e37ba75e68da 100644
> >--- a/drivers/gpu/drm/i915/display/intel_dmc.c
> >+++ b/drivers/gpu/drm/i915/display/intel_dmc.c
> >@@ -374,6 +374,44 @@ static void dmc_set_fw_offset(struct intel_dmc
> *dmc,
> > 	}
> > }
> >
> >+static bool dmc_mmio_addr_sanity_check(struct intel_dmc *dmc, const
> u32 *mmioaddr,
> >+				       u32 mmio_count, int header_ver, u8
> dmc_id) {
> >+	struct drm_i915_private *i915 = container_of(dmc, typeof(*i915),
> dmc);
> >+	u32 start_range, end_range;
> >+	int i;
> >+
> >+	if (dmc_id >= DMC_FW_MAX || dmc_id < DMC_FW_MAIN) {
> 
> dmc_id is unsigned and DMC_FW_MAIN is 0. dmc_id < DMC_FW_MAIN can't
> ever possibly happen so you can remove it.
> 
> >+		drm_warn(&i915->drm, "Unsupported firmware id %u\n",
> dmc_id);
> >+		return false;
> >+	}
> >+
> >+	if (header_ver == 1) {
> >+		start_range = DMC_MMIO_START_RANGE;
> >+		end_range = DMC_MMIO_END_RANGE;
> >+	} else if (dmc_id == DMC_FW_MAIN) {
> >+		start_range = TGL_MAIN_MMIO_START;
> >+		end_range = TGL_MAIN_MMIO_END;
> >+	} else if (IS_DG2(i915) || IS_ALDERLAKE_P(i915)) {
> 
> 	} else if (DISPLAY_VER(i915) >= 13) {
> 
> ?
> 
> >+		start_range = ADLP_PIPE_MMIO_START;
> >+		end_range = ADLP_PIPE_MMIO_END;
> >+	} else if (IS_TIGERLAKE(i915) || IS_DG1(i915) ||
> IS_ALDERLAKE_S(i915) ||
> >+		   IS_ROCKETLAKE(i915)) {
> 
> 	} else if (DISPLAY_VER(i915) >= 12) {
> 
> ?
> 
> maintaining the if/else ladder fine grained by platform is somewhat painful.

Agreed.

> >+		start_range = TGL_PIPE_MMIO_START(dmc_id);
> >+		end_range = TGL_PIPE_MMIO_END(dmc_id);
> >+	} else {
> >+		drm_warn(&i915->drm, "Unknown mmio range for sanity
> check");
> >+		return false;
> >+	}
> >+
> >+	for (i = 0; i < mmio_count; i++) {
> >+		if (mmioaddr[i] < start_range || mmioaddr[i] > end_range)
> >+			return false;
> >+	}
> >+
> >+	return true;
> >+}
> >+
> > static u32 parse_dmc_fw_header(struct intel_dmc *dmc,
> > 			       const struct intel_dmc_header_base
> *dmc_header,
> > 			       size_t rem_size, u8 dmc_id)
> >@@ -443,6 +481,11 @@ static u32 parse_dmc_fw_header(struct intel_dmc
> *dmc,
> > 		return 0;
> > 	}
> >
> >+	if (!dmc_mmio_addr_sanity_check(dmc, mmioaddr, mmio_count,
> dmc_header->header_ver, dmc_id)) {
> >+		drm_err(&i915->drm, "DMC firmware has Wrong MMIO
> Addresses\n");
> >+		return 0;
> >+	}
> >+
> > 	for (i = 0; i < mmio_count; i++) {
> > 		dmc_info->mmioaddr[i] = _MMIO(mmioaddr[i]);
> > 		dmc_info->mmiodata[i] = mmiodata[i]; diff --git
> >a/drivers/gpu/drm/i915/display/intel_dmc_regs.h
> >b/drivers/gpu/drm/i915/display/intel_dmc_regs.h
> >index d65e698832eb..67e14eb96a7a 100644
> >--- a/drivers/gpu/drm/i915/display/intel_dmc_regs.h
> >+++ b/drivers/gpu/drm/i915/display/intel_dmc_regs.h
> >@@ -16,7 +16,23 @@
> > #define DMC_LAST_WRITE		_MMIO(0x8F034)
> > #define DMC_LAST_WRITE_VALUE	0xc003b400
> > #define DMC_MMIO_START_RANGE	0x80000
> >-#define DMC_MMIO_END_RANGE	0x8FFFF
> >+#define DMC_MMIO_END_RANGE     0x8FFFF
> >+#define DMC_V1_MMIO_START_RANGE		0x80000
> >+#define TGL_MAIN_MMIO_START		0x8F000
> >+#define TGL_MAIN_MMIO_END		0x8FFFF
> >+#define _TGL_PIPEA_MMIO_START		0x92000
> >+#define _TGL_PIPEA_MMIO_END		0x93FFF
> >+#define _TGL_PIPEB_MMIO_START		0x96000
> >+#define _TGL_PIPEB_MMIO_END		0x97FFF
> >+#define ADLP_PIPE_MMIO_START		0x5F000
> >+#define ADLP_PIPE_MMIO_END		0x5FFFF
> 
> don't we have per-pipe range for ADLP_? Or is there only pipe A?
> 
We don't have per-pipe range. We have one big chunk of range for all pipe DMC MMIOs.

> with the above fixes, feel free to add my Reviewed-by: Lucas De Marchi
> <lucas.demarchi@intel.com> in the next version.

Thanks!
 
> Lucas De Marchi
> 
> >+
> >+#define TGL_PIPE_MMIO_START(dmc_id)	_PICK_EVEN(((dmc_id) - 1),
> _TGL_PIPEA_MMIO_START,\
> >+					      _TGL_PIPEB_MMIO_START)
> >+
> >+#define TGL_PIPE_MMIO_END(dmc_id)	_PICK_EVEN(((dmc_id) - 1),
> _TGL_PIPEA_MMIO_END,\
> >+					      _TGL_PIPEB_MMIO_END)
> >+
> > #define SKL_DMC_DC3_DC5_COUNT	_MMIO(0x80030)
> > #define SKL_DMC_DC5_DC6_COUNT	_MMIO(0x8002C)
> > #define BXT_DMC_DC3_DC5_COUNT	_MMIO(0x80038)
> >--
> >2.25.1
> >