[Intel-gfx] [RFC PATCH 1/9] drm/i915/spi: add spi device for discrete graphics

[Tomas Winkler <tomas.winkler@intel.com>]

Enable access to internal spi on descrete devices via a child device.
The spi child device is exposed via MFD framework.

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com> # v3
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
 drivers/gpu/drm/i915/Kconfig         |  1 +
 drivers/gpu/drm/i915/Makefile        |  3 ++
 drivers/gpu/drm/i915/i915_drv.c      |  9 +++++
 drivers/gpu/drm/i915/i915_drv.h      |  4 +++
 drivers/gpu/drm/i915/i915_reg.h      |  1 +
 drivers/gpu/drm/i915/spi/intel_spi.c | 53 ++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/spi/intel_spi.h | 19 ++++++++++
 7 files changed, 90 insertions(+)
 create mode 100644 drivers/gpu/drm/i915/spi/intel_spi.c
 create mode 100644 drivers/gpu/drm/i915/spi/intel_spi.h

diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
index 1e1cb245fca7..abcaa8da45ac 100644
--- a/drivers/gpu/drm/i915/Kconfig
+++ b/drivers/gpu/drm/i915/Kconfig
@@ -26,6 +26,7 @@ config DRM_I915
 	select SND_HDA_I915 if SND_HDA_CORE
 	select CEC_CORE if CEC_NOTIFIER
 	select VMAP_PFN
+	select MFD_CORE
 	help
 	  Choose this option if you have a system that has "Intel Graphics
 	  Media Accelerator" or "HD Graphics" integrated graphics,
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 235679637d1c..7fa9120feb8d 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -191,6 +191,9 @@ i915-y += gt/uc/intel_uc.o \
 	  gt/uc/intel_huc_debugfs.o \
 	  gt/uc/intel_huc_fw.o
 
+# graphics spi device (DGFX) support
+i915-y += spi/intel_spi.o
+
 # modesetting core code
 i915-y += \
 	display/intel_atomic.o \
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 3edd5e47ad68..48c383d37212 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -38,6 +38,7 @@
 #include <linux/slab.h>
 #include <linux/vga_switcheroo.h>
 #include <linux/vt.h>
+#include <linux/mfd/core.h>
 
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_ioctl.h>
@@ -67,6 +68,8 @@
 #include "gt/intel_gt_pm.h"
 #include "gt/intel_rc6.h"
 
+#include "spi/intel_spi.h"
+
 #include "i915_debugfs.h"
 #include "i915_drm_client.h"
 #include "i915_drv.h"
@@ -684,6 +687,8 @@ static void i915_driver_register(struct drm_i915_private *dev_priv)
 
 	intel_gt_driver_register(&dev_priv->gt);
 
+	intel_spi_init(&dev_priv->spi, dev_priv);
+
 	intel_display_driver_register(dev_priv);
 
 	intel_power_domains_enable(dev_priv);
@@ -710,6 +715,10 @@ static void i915_driver_unregister(struct drm_i915_private *dev_priv)
 
 	intel_display_driver_unregister(dev_priv);
 
+	mfd_remove_devices(&dev_priv->drm.pdev->dev);
+
+	intel_spi_fini(&dev_priv->spi);
+
 	intel_gt_driver_unregister(&dev_priv->gt);
 
 	i915_perf_unregister(dev_priv);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index f8413b3b9da8..f12ec7606d75 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -85,6 +85,8 @@
 #include "gt/intel_workarounds.h"
 #include "gt/uc/intel_uc.h"
 
+#include "spi/intel_spi.h"
+
 #include "intel_device_info.h"
 #include "intel_pch.h"
 #include "intel_runtime_pm.h"
@@ -1117,6 +1119,8 @@ struct drm_i915_private {
 
 	struct i915_perf perf;
 
+	struct intel_spi spi;
+
 	/* Abstract the submission mechanism (legacy ringbuffer or execlists) away */
 	struct intel_gt gt;
 
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 224ad897af34..426c5dd63673 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2510,6 +2510,7 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
 #define VEBOX_RING_BASE		0x1a000
 #define GEN11_VEBOX_RING_BASE		0x1c8000
 #define GEN11_VEBOX2_RING_BASE		0x1d8000
+#define GEN12_GUNIT_SPI_BASE	0x00102040
 #define BLT_RING_BASE		0x22000
 #define RING_TAIL(base)		_MMIO((base) + 0x30)
 #define RING_HEAD(base)		_MMIO((base) + 0x34)
diff --git a/drivers/gpu/drm/i915/spi/intel_spi.c b/drivers/gpu/drm/i915/spi/intel_spi.c
new file mode 100644
index 000000000000..07da7197bd5d
--- /dev/null
+++ b/drivers/gpu/drm/i915/spi/intel_spi.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright(c) 2019-2021, Intel Corporation. All rights reserved.
+ */
+
+#include <linux/mfd/core.h>
+#include <linux/irq.h>
+#include "i915_reg.h"
+#include "i915_drv.h"
+#include "gt/intel_gt.h"
+#include "spi/intel_spi.h"
+
+static const struct resource spi_resources[] = {
+	DEFINE_RES_MEM_NAMED(GEN12_GUNIT_SPI_BASE, 0x80, "i915-spi-mmio"),
+};
+
+static const struct mfd_cell intel_spi_cell = {
+	.id = 2,
+	.name = "i915-spi",
+	.num_resources = ARRAY_SIZE(spi_resources),
+	.resources = spi_resources,
+};
+
+void intel_spi_init(struct intel_spi *spi, struct drm_i915_private *dev_priv)
+{
+	struct pci_dev *pdev = dev_priv->drm.pdev;
+	int ret;
+
+	/* Only the DGFX devices have internal SPI */
+	if (!IS_DGFX(dev_priv))
+		return;
+
+	ret = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO,
+			      &intel_spi_cell, 1,
+			      &pdev->resource[0], -1, NULL);
+
+	if (ret)
+		dev_err(&pdev->dev, "creating i915-spi cell failed\n");
+
+	spi->i915 = dev_priv;
+}
+
+void intel_spi_fini(struct intel_spi *spi)
+{
+	struct pci_dev *pdev;
+
+	if (!spi->i915)
+		return;
+
+	pdev = spi->i915->drm.pdev;
+
+	dev_dbg(&pdev->dev, "removing i915-spi cell\n");
+}
diff --git a/drivers/gpu/drm/i915/spi/intel_spi.h b/drivers/gpu/drm/i915/spi/intel_spi.h
new file mode 100644
index 000000000000..276551fed993
--- /dev/null
+++ b/drivers/gpu/drm/i915/spi/intel_spi.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright(c) 2019-2021, Intel Corporation. All rights reserved.
+ */
+
+#ifndef __INTEL_SPI_DEV_H__
+#define __INTEL_SPI_DEV_H__
+
+struct drm_i915_private;
+
+struct intel_spi {
+	struct drm_i915_private *i915;
+};
+
+void intel_spi_init(struct intel_spi *spi, struct drm_i915_private *i915);
+
+void intel_spi_fini(struct intel_spi *spi);
+
+#endif /* __INTEL_SPI_DEV_H__ */
-- 
2.26.2

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