linux-kernel - [PATCH 8/9] nvme-apple: Add support for multiple power domains

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Date:   Mon, 21 Mar 2022 17:50:48 +0100
From:   Sven Peter <sven@...npeter.dev>
To:     Keith Busch <kbusch@...nel.org>, Jens Axboe <axboe@...com>,
        Christoph Hellwig <hch@....de>,
        Sagi Grimberg <sagi@...mberg.me>
Cc:     Sven Peter <sven@...npeter.dev>, Hector Martin <marcan@...can.st>,
        Alyssa Rosenzweig <alyssa@...enzweig.io>,
        Rob Herring <robh+dt@...nel.org>,
        Arnd Bergmann <arnd@...db.de>, Marc Zyngier <maz@...nel.org>,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, linux-nvme@...ts.infradead.org
Subject: [PATCH 8/9] nvme-apple: Add support for multiple power domains

From: Hector Martin <marcan@...can.st>

Turns out we really need this, as the APCIE_ST*_SYS domains really do
hard-depend on ANS2, at least on t6000.

Signed-off-by: Hector Martin <marcan@...can.st>
Signed-off-by: Sven Peter <sven@...npeter.dev>
---
 drivers/nvme/host/apple.c | 67 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)

diff --git a/drivers/nvme/host/apple.c b/drivers/nvme/host/apple.c
index a4193429564e..d89b4ab80169 100644
--- a/drivers/nvme/host/apple.c
+++ b/drivers/nvme/host/apple.c
@@ -29,6 +29,7 @@
 #include <linux/of_platform.h>
 #include <linux/once.h>
 #include <linux/platform_device.h>
+#include <linux/pm_domain.h>
 #include <linux/soc/apple/rtkit.h>
 #include <linux/soc/apple/sart.h>
 #include <linux/reset.h>
@@ -178,6 +179,10 @@ struct apple_nvme {
 	void __iomem *mmio_coproc;
 	void __iomem *mmio_nvme;
 
+	struct device **pd_dev;
+	struct device_link **pd_link;
+	int pd_count;
+
 	struct apple_sart *sart;
 	struct apple_rtkit *rtk;
 	struct reset_control *reset;
@@ -1313,6 +1318,62 @@ static int apple_nvme_queue_alloc(struct apple_nvme *anv,
 	return 0;
 }
 
+static void apple_nvme_detach_genpd(struct apple_nvme *anv)
+{
+	int i;
+
+	if (anv->pd_count <= 1)
+		return;
+
+	for (i = anv->pd_count - 1; i >= 0; i--) {
+		if (anv->pd_link[i])
+			device_link_del(anv->pd_link[i]);
+		if (!IS_ERR_OR_NULL(anv->pd_dev[i]))
+			dev_pm_domain_detach(anv->pd_dev[i], true);
+	}
+}
+
+static int apple_nvme_attach_genpd(struct apple_nvme *anv)
+{
+	struct device *dev = anv->dev;
+	int i;
+
+	anv->pd_count = of_count_phandle_with_args(dev->of_node,
+						   "power-domains",
+						   "#power-domain-cells");
+	if (anv->pd_count <= 1)
+		return 0;
+
+	anv->pd_dev = devm_kcalloc(dev, anv->pd_count, sizeof(*anv->pd_dev),
+				   GFP_KERNEL);
+	if (!anv->pd_dev)
+		return -ENOMEM;
+
+	anv->pd_link = devm_kcalloc(dev, anv->pd_count, sizeof(*anv->pd_link),
+				    GFP_KERNEL);
+	if (!anv->pd_link)
+		return -ENOMEM;
+
+	for (i = 0; i < anv->pd_count; i++) {
+		anv->pd_dev[i] = dev_pm_domain_attach_by_id(dev, i);
+		if (IS_ERR(anv->pd_dev[i])) {
+			apple_nvme_detach_genpd(anv);
+			return PTR_ERR(anv->pd_dev[i]);
+		}
+
+		anv->pd_link[i] = device_link_add(dev, anv->pd_dev[i],
+						  DL_FLAG_STATELESS |
+						  DL_FLAG_PM_RUNTIME |
+						  DL_FLAG_RPM_ACTIVE);
+		if (!anv->pd_link[i]) {
+			apple_nvme_detach_genpd(anv);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
 static int apple_nvme_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -1327,6 +1388,10 @@ static int apple_nvme_probe(struct platform_device *pdev)
 	anv->adminq.is_adminq = true;
 	platform_set_drvdata(pdev, anv);
 
+	ret = apple_nvme_attach_genpd(anv);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Failed to attach power domains");
+
 	if (dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64)))
 		return -ENXIO;
 
@@ -1435,6 +1500,8 @@ static int apple_nvme_remove(struct platform_device *pdev)
 	if (apple_rtkit_is_running(anv->rtk))
 		apple_rtkit_shutdown(anv->rtk);
 
+	apple_nvme_detach_genpd(anv);
+
 	return 0;
 }
 
-- 
2.25.1