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[DOWNSTREAM]: iommu/tegra241-cmdqv: WAR for 64-bit writes on NV HV

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NVIDIA’s hypervisor does not support 64-bit writes to consecutive
two 32-bit registers e.g., VCMDQ_BASE_LO and VCMDQ_BASE_HI. The driver
currently issues a 64-bit write to such registers, which works fine on
real hardware but fails under NV HV.
This is not a functional bug in the driver, but rather a quirk of the
hypervisor which does not fully emulate the HW behavior. Add a workaround
to split the write into two 32-bit accesses.

Bug 5111712

Change-Id: I6fb6a926a80326e2d7a8a2ec9e475106af843f7c
Signed-off-by: Ashish Mhetre <amhetre@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/3rdparty/canonical/linux-noble/+/3439898
Reviewed-by: Pritesh Raithatha <praithatha@nvidia.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
GVS: buildbot_gerritrpt <buildbot_gerritrpt@nvidia.com>
This commit is contained in:
Ashish Mhetre
2025-08-26 05:24:07 +00:00
parent 9cbafdf4c3
commit c16f161cd7
1 changed files with 10 additions and 5 deletions
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15
drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
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@@ -82,8 +82,10 @@
#define VCMDQ_ADDR GENMASK(47, 5)
#define VCMDQ_LOG2SIZE GENMASK(4, 0)
#define TEGRA241_VCMDQ_BASE 0x00000
#define TEGRA241_VCMDQ_CONS_INDX_BASE 0x00008
#define TEGRA241_VCMDQ_BASE 0x00000
#define TEGRA241_VCMDQ_BASE_H 0x00004
#define TEGRA241_VCMDQ_CONS_INDX_BASE 0x00008
#define TEGRA241_VCMDQ_CONS_INDX_BASE_H 0x0000C
/* VINTF logical-VCMDQ pages */
#define TEGRA241_VINTFi_PAGE0(i) (TEGRA241_VINTF_PAGE_BASE + SZ_128K*(i))
@@ -367,8 +369,10 @@ static void tegra241_vcmdq_hw_deinit(struct tegra241_vcmdq *vcmdq)
}
writel_relaxed(0, REG_VCMDQ_PAGE0(vcmdq, PROD));
writel_relaxed(0, REG_VCMDQ_PAGE0(vcmdq, CONS));
writeq_relaxed(0, REG_VCMDQ_PAGE1(vcmdq, BASE));
writeq_relaxed(0, REG_VCMDQ_PAGE1(vcmdq, CONS_INDX_BASE));
writel_relaxed(0, REG_VCMDQ_PAGE1(vcmdq, BASE_H));
writel_relaxed(0, REG_VCMDQ_PAGE1(vcmdq, BASE));
writel_relaxed(0, REG_VCMDQ_PAGE1(vcmdq, CONS_INDX_BASE_H));
writel_relaxed(0, REG_VCMDQ_PAGE1(vcmdq, CONS_INDX_BASE));
gerrorn = readl_relaxed(REG_VCMDQ_PAGE0(vcmdq, GERRORN));
gerror = readl_relaxed(REG_VCMDQ_PAGE0(vcmdq, GERROR));
@@ -390,7 +394,8 @@ static int tegra241_vcmdq_hw_init(struct tegra241_vcmdq *vcmdq)
tegra241_vcmdq_hw_deinit(vcmdq);
/* Configure and enable VCMDQ */
writeq_relaxed(vcmdq->cmdq.q.q_base, REG_VCMDQ_PAGE1(vcmdq, BASE));
writel_relaxed(upper_32_bits(vcmdq->cmdq.q.q_base), REG_VCMDQ_PAGE1(vcmdq, BASE_H));
writel_relaxed(lower_32_bits(vcmdq->cmdq.q.q_base), REG_VCMDQ_PAGE1(vcmdq, BASE));
ret = vcmdq_write_config(vcmdq, VCMDQ_EN);
if (ret) {