From 6e55d273708b2a9485eb7c035efd2757fdae1869 Mon Sep 17 00:00:00 2001 From: Alexey Sheplyakov Date: Sat, 15 Jan 2022 20:06:58 +0400 Subject: [PATCH] drm/panfrost: initial dual core group GPUs support On a dual core group GPUs (such as T628) fragment shading can be performed over all cores (because a fragment shader job doesn't need coherency between threads), however vertex shading requires to be run on the same core group as the tiler (which always lives in core group 0). As a first step to support T628 power on only the first core group (so no jobs are scheduled on the second one). This makes T628 look like every other Midgard GPU (and throws away up to half the cores). With this patch panfrost is able to drive T628 (r1p0) GPU on some armv8 SoCs (in particular BE-M1000). Without the patch rendering is horribly broken (desktop is completely unusable) and eventually the GPU locks up (it takes from a few seconds to a couple of minutes). Using the second core group requires support in Mesa (and an UABI change): the userspace should 1) set PANFROST_JD_DOESNT_NEED_COHERENCY_ON_GPU flag to opt-in to allowing the job to run across all cores. 2) set PANFROST_RUN_ON_SECOND_CORE_GROUP flag to allow compute jobs to be run on the second core group (at the moment Mesa does not advertise compute support on anything older than Mali T760) But there's little point adding such flags until someone (myself) steps up to do the Mesa work. Signed-off-by: Alexey Sheplyakov Signed-off-by: Vadim V. Vlasov Tested-by: Alexey Sheplyakov Co-developed-by: Steven Price Signed-off-by: Steven Price Link: https://patchwork.freedesktop.org/patch/msgid/20220115160658.582646-1-asheplyakov@basealt.ru --- drivers/gpu/drm/panfrost/panfrost_gpu.c | 27 ++++++++++++++++++++++----- 1 file changed, 22 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c index f8355de..15cec83 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gpu.c +++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c @@ -320,19 +320,36 @@ void panfrost_gpu_power_on(struct panfrost_device *pfdev) { int ret; u32 val; + u64 core_mask = U64_MAX; panfrost_gpu_init_quirks(pfdev); - /* Just turn on everything for now */ - gpu_write(pfdev, L2_PWRON_LO, pfdev->features.l2_present); + if (pfdev->features.l2_present != 1) { + /* + * Only support one core group now. + * ~(l2_present - 1) unsets all bits in l2_present except + * the bottom bit. (l2_present - 2) has all the bits in + * the first core group set. AND them together to generate + * a mask of cores in the first core group. + */ + core_mask = ~(pfdev->features.l2_present - 1) & + (pfdev->features.l2_present - 2); + dev_info_once(pfdev->dev, "using only 1st core group (%lu cores from %lu)\n", + hweight64(core_mask), + hweight64(pfdev->features.shader_present)); + } + gpu_write(pfdev, L2_PWRON_LO, pfdev->features.l2_present & core_mask); ret = readl_relaxed_poll_timeout(pfdev->iomem + L2_READY_LO, - val, val == pfdev->features.l2_present, 100, 20000); + val, val == (pfdev->features.l2_present & core_mask), + 100, 20000); if (ret) dev_err(pfdev->dev, "error powering up gpu L2"); - gpu_write(pfdev, SHADER_PWRON_LO, pfdev->features.shader_present); + gpu_write(pfdev, SHADER_PWRON_LO, + pfdev->features.shader_present & core_mask); ret = readl_relaxed_poll_timeout(pfdev->iomem + SHADER_READY_LO, - val, val == pfdev->features.shader_present, 100, 20000); + val, val == (pfdev->features.shader_present & core_mask), + 100, 20000); if (ret) dev_err(pfdev->dev, "error powering up gpu shader"); -- 2.7.4