dmaengine: apple-sio: select firmware behavior from compatible data

Documentation/devicetree/bindings/dma/apple,sio.yaml

@@ -9,7 +9,9 @@ title: Apple SIO Coprocessor
 description:
   SIO is a coprocessor on Apple M1 and later chips (and maybe also on earlier
   chips). Its role is to offload SPI, UART and DisplayPort audio transfers,
-  being a pretend DMA controller.
+  being a pretend DMA controller. The SoC-specific compatible selects the
+  firmware protocol and channel configuration. In particular, apple,t6030-sio
+  requires protocol-10 boot tables before the coprocessor can be started.
 
 maintainers:
   - Martin Povišer <povik+lin@cutebit.org>

arch/arm64/configs/asahi.config

@@ -61,7 +61,6 @@ CONFIG_USB_XHCI_PCI_ASMEDIA=y
 CONFIG_TYPEC_SN201202X=m
 CONFIG_RTC_DRV_APPLE_PMU=m
 CONFIG_APPLE_SIO=m
-CONFIG_APPLE_SIO_T6030=y
 CONFIG_APPLE_DART=y
 CONFIG_APPLE_DART_J713_DCP=y
 CONFIG_APPLE_DOCKCHANNEL=m

drivers/dma/Kconfig

@@ -111,26 +111,12 @@ config APPLE_SIO_KUNIT_TEST
 	default KUNIT_ALL_TESTS
 	help
 	  Check which SIO device-tree nodes the probe goes on with: the
-	  generic SIO of the M1 and M2 in every configuration, and a T6030
-	  SIO only with APPLE_SIO_T6030 and protocol-10 boot tables. Run it
-	  both with and without APPLE_SIO_T6030.
-
-config APPLE_SIO_T6030
-	bool "Apple SIO on the M3 Pro (T6030)"
-	depends on APPLE_SIO
-	help
-	  Configure the SIO channels of the T6030 (apple,t6030-sio) the way
-	  its firmware expects them: the DisplayPort audio channels refill
-	  their FIFO at the threshold the system's device tree records for
-	  them (0x600 bytes, not 0x800), and every period descriptor is
-	  published whole. The firmware's boot tables come from the boot
-	  loader, as on the other SoCs; the SIO is only started when they
-	  are protocol-10 tables, which a boot loader without T6030 support
-	  does not build. Without this option a T6030 SIO is left stopped.
+	  generic SIO of the M1 and M2, and a T6030 SIO only with validated
+	  protocol-10 boot tables. The compatible selects the firmware layout.
 
 config APPLE_SIO_T6030_KUNIT_TEST
 	bool "KUnit tests for the T6030 SIO boot-table check" if !KUNIT_ALL_TESTS
-	depends on APPLE_SIO=y && APPLE_SIO_T6030 && KUNIT=y
+	depends on APPLE_SIO=y && KUNIT=y
 	depends on OF_OVERLAY
 	default KUNIT_ALL_TESTS
 	help

drivers/dma/apple-sio-probe-test.c

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only OR MIT
 /*
- * Included by apple-sio.c: which SIO nodes the probe goes on with, with and
- * without APPLE_SIO_T6030. The test devices have no register range, so a probe
+ * Included by apple-sio.c: the compatible selects which firmware tables a
+ * node needs. The test devices have no register range, so a probe
  * that goes on toward the hardware stops there with -EINVAL; a refused node
  * returns -ENODEV first.
  */
@@ -13,16 +13,17 @@ OF_OVERLAY_DECLARE(apple_sio_probe_test);
 
 static void sio_probe_nodes_test(struct kunit *test)
 {
-	const bool t6030 = IS_ENABLED(CONFIG_APPLE_SIO_T6030);
 	const struct {
 		const char *path;
 		int err;
 	} cases[] = {
-		/* M1/M2: the generic SIO, either way */
+		/* M1/M2: the generic SIO */
 		{ "/sio-probe-test/sio-probe-test-t8103", -EINVAL },
-		/* T6030: only with its support built, and with protocol-10 tables */
-		{ "/sio-probe-test/sio-probe-test-t6030-v10", t6030 ? -EINVAL : -ENODEV },
+		/* T6030: protocol-10 tables select the admitted path */
+		{ "/sio-probe-test/sio-probe-test-t6030-v10", -EINVAL },
 		{ "/sio-probe-test/sio-probe-test-t6030-earlier", -ENODEV },
+		{ "/sio-probe-test/sio-probe-test-t6030-missing", -ENODEV },
+		{ "/sio-probe-test/sio-probe-test-unknown", -ENODEV },
 	};
 	unsigned int i;
 
@@ -38,15 +39,44 @@ static void sio_probe_nodes_test(struct kunit *test)
 		KUNIT_ASSERT_NOT_NULL_MSG(test, pdev->dev.of_node, "%s", cases[i].path);
 		mask = pdev->dev.coherent_dma_mask;
 		KUNIT_EXPECT_EQ_MSG(test, sio_probe(pdev), cases[i].err, "%s", cases[i].path);
-		/* Without its support, a T6030 is refused before its DMA is set up */
-		if (!t6030 && cases[i].err == -ENODEV)
+		/* Bad protocol tables are refused before DMA setup. */
+		if (cases[i].err == -ENODEV)
 			KUNIT_EXPECT_EQ_MSG(test, pdev->dev.coherent_dma_mask, mask, "%s",
 					    cases[i].path);
 	}
 }
 
+static void sio_match_data_test(struct kunit *test)
+{
+	const struct of_device_id *match;
+	struct device_node *np;
+	const struct sio_hw_data *hw;
+
+	KUNIT_ASSERT_EQ(test, 0, of_overlay_apply_kunit(test, apple_sio_probe_test));
+	np = of_find_node_by_path("/sio-probe-test/sio-probe-test-t6030-v10");
+	KUNIT_ASSERT_NOT_NULL(test, np);
+	match = of_match_node(sio_of_match, np);
+	of_node_put(np);
+	KUNIT_ASSERT_NOT_NULL(test, match);
+	hw = match->data;
+	KUNIT_EXPECT_EQ(test, hw->fifo_threshold, 0x600U);
+	KUNIT_EXPECT_TRUE(test, hw->clear_period_desc);
+	KUNIT_EXPECT_TRUE(test, hw->check_boot_tables == sio_t6030_check_boot_tables);
+
+	np = of_find_node_by_path("/sio-probe-test/sio-probe-test-t8103");
+	KUNIT_ASSERT_NOT_NULL(test, np);
+	match = of_match_node(sio_of_match, np);
+	of_node_put(np);
+	KUNIT_ASSERT_NOT_NULL(test, match);
+	hw = match->data;
+	KUNIT_EXPECT_EQ(test, hw->fifo_threshold, 0x800U);
+	KUNIT_EXPECT_FALSE(test, hw->clear_period_desc);
+	KUNIT_EXPECT_FALSE(test, hw->check_boot_tables);
+}
+
 static struct kunit_case sio_probe_test_cases[] = {
 	KUNIT_CASE(sio_probe_nodes_test),
+	KUNIT_CASE(sio_match_data_test),
 	{}
 };
 

drivers/dma/apple-sio-probe-test.dtso

@@ -17,6 +17,16 @@
 			dma-channels = <8>;
 		};
 
+		sio-probe-test-t6030-missing {
+			compatible = "apple,t6030-sio", "apple,sio";
+			dma-channels = <8>;
+		};
+
+		sio-probe-test-unknown {
+			compatible = "apple,sio-probe-test-unknown";
+			dma-channels = <8>;
+		};
+
 		v10_w: v10-w {
 			iommu-addresses = <&v10 0x0 0x30000 0x0 0x4000>, <&v10 0x0 0x34000 0x0 0x20000>,
 					  <&v10 0x0 0x54000 0x0 0x4000>, <&v10 0x0 0x58000 0x0 0x4000>;

drivers/dma/apple-sio.c

@@ -108,7 +108,14 @@ struct sio_chan {
 
 typedef void (*sio_ack_callback)(struct sio_chan *, void *, bool);
 
+struct sio_hw_data {
+	u32 fifo_threshold;
+	bool clear_period_desc;
+	int (*check_boot_tables)(struct device *dev);
+};
+
 struct sio_data {
+	const struct sio_hw_data *hw;
 	void __iomem *base;
 	struct dma_device dma;
 	struct device *dev;
@@ -130,9 +137,6 @@ struct sio_data {
 	} tags;
 
 	int nchannels;
-#if IS_ENABLED(CONFIG_APPLE_SIO_T6030)
-	bool t6030;
-#endif
 	struct sio_chan channels[];
 };
 
@@ -155,16 +159,6 @@ static int sio_send_siomsg_atomic(struct sio_data *sio, u64 msg,
 				  void *cookie);
 static int sio_call(struct sio_data *sio, u64 msg);
 
-static inline bool sio_is_t6030(struct sio_data *sio)
-{
-#if IS_ENABLED(CONFIG_APPLE_SIO_T6030)
-	return sio->t6030;
-#else
-	return false;
-#endif
-}
-
-#if IS_ENABLED(CONFIG_APPLE_SIO_T6030)
 /*
  * Boot tables of the T6030 SIO firmware, protocol 10. The boot loader builds them from the ADT
  * and passes each one as two apple,sio-firmware-params: the table's IOVA page under its key and
@@ -320,7 +314,23 @@ static int sio_t6030_check_boot_tables(struct device *dev)
 	}
 	return 0;
 }
-#endif
+
+static const struct sio_hw_data sio_hw_generic = {
+	.fifo_threshold = 0x800,
+};
+
+static const struct sio_hw_data sio_hw_t6030 = {
+	.fifo_threshold = 0x600,
+	.clear_period_desc = true,
+	.check_boot_tables = sio_t6030_check_boot_tables,
+};
+
+static const struct of_device_id sio_of_match[] = {
+	{ .compatible = "apple,t6030-sio", .data = &sio_hw_t6030 },
+	{ .compatible = "apple,sio", .data = &sio_hw_generic },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, sio_of_match);
 
 static struct sio_chan *to_sio_chan(struct dma_chan *chan)
 {
@@ -459,7 +469,7 @@ static struct dma_async_tx_descriptor *sio_prep_dma_cyclic(
 		 * T6030: publish the whole descriptor, its other fields zero;
 		 * a slot may come back from an earlier transfer.
 		 */
-		if (sio_is_t6030(siochan->host))
+		if (siochan->host->hw->clear_period_desc)
 			memset(d, 0, sizeof(*d));
 		d->flag = 1; /* not sure what's up with this */
 		d->iova = buf_addr + period_len * i;
@@ -839,7 +849,7 @@ static int sio_device_config(struct dma_chan *chan,
 	 * dp-audioN dma-channels: channel, data shape, timeout, FIFO size,
 	 * threshold). T6030's DisplayPort audio channels refill at 0x600.
 	 */
-	cfg.threshold = sio_is_t6030(sio) ? 0x600 : 0x800;
+	cfg.threshold = sio->hw->fifo_threshold;
 
 	/*
 	 * Dmaengine prescribes we ought to apply the new configuration only
@@ -967,20 +977,23 @@ static int sio_send_dt_params(struct sio_data *sio)
 static int sio_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
+	const struct of_device_id *match;
+	const struct sio_hw_data *hw;
 	struct sio_data *sio;
 	struct dma_device *dma;
 	int nchannels;
 	int err, i;
 
-	/*
-	 * Only APPLE_SIO_T6030 checks a T6030's boot tables and configures its
-	 * channels: without it, leave the SIO stopped rather than start it as
-	 * the generic one.
-	 */
-	if (!IS_ENABLED(CONFIG_APPLE_SIO_T6030) &&
-	    of_device_is_compatible(np, "apple,t6030-sio"))
-		return dev_err_probe(&pdev->dev, -ENODEV,
-				     "T6030 SIO support (APPLE_SIO_T6030) not built; leaving the SIO stopped\n");
+	match = of_match_node(sio_of_match, np);
+	if (!match)
+		return -ENODEV;
+	hw = match->data;
+	/* Refuse incompatible firmware tables before DMA or hardware setup. */
+	if (hw->check_boot_tables) {
+		err = hw->check_boot_tables(&pdev->dev);
+		if (err)
+			return err;
+	}
 
 	err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(42));
 	if (err)
@@ -998,15 +1011,7 @@ static int sio_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, sio);
 	sio->dev = &pdev->dev;
 	sio->nchannels = nchannels;
-#if IS_ENABLED(CONFIG_APPLE_SIO_T6030)
-	sio->t6030 = of_device_is_compatible(np, "apple,t6030-sio");
-	/* Before any register, power or firmware access */
-	if (sio->t6030) {
-		err = sio_t6030_check_boot_tables(&pdev->dev);
-		if (err)
-			return err;
-	}
-#endif
+	sio->hw = hw;
 
 	sio->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(sio->base))
@@ -1107,12 +1112,6 @@ static void sio_remove(struct platform_device *pdev)
 	dma_async_device_unregister(&sio->dma);
 }
 
-static const struct of_device_id sio_of_match[] = {
-	{ .compatible = "apple,sio", },
-	{ }
-};
-MODULE_DEVICE_TABLE(of, sio_of_match);
-
 static __maybe_unused int sio_suspend(struct device *dev)
 {
 	/*