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From: Leonardo Bras <leobras.c@gmail.com>
To: Michael Ellerman <mpe@ellerman.id.au>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Leonardo Bras <leobras.c@gmail.com>,
	Alexey Kardashevskiy <aik@ozlabs.ru>,
	David Gibson <david@gibson.dropbear.id.au>,
	kernel test robot <lkp@intel.com>,
	Nicolin Chen <nicoleotsuka@gmail.com>,
	Frederic Barrat <fbarrat@linux.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [PATCH v5 05/11] powerpc/pseries/iommu: Allow DDW windows starting at 0x00
Date: Fri, 16 Jul 2021 05:27:50 -0300	[thread overview]
Message-ID: <20210716082755.428187-6-leobras.c@gmail.com> (raw)
In-Reply-To: <20210716082755.428187-1-leobras.c@gmail.com>

enable_ddw() currently returns the address of the DMA window, which is
considered invalid if has the value 0x00.

Also, it only considers valid an address returned from find_existing_ddw
if it's not 0x00.

Changing this behavior makes sense, given the users of enable_ddw() only
need to know if direct mapping is possible. It can also allow a DMA window
starting at 0x00 to be used.

This will be helpful for using a DDW with indirect mapping, as the window
address will be different than 0x00, but it will not map the whole
partition.

Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/platforms/pseries/iommu.c | 36 +++++++++++++-------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 712d1667144a..b34b473bbdc1 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -853,25 +853,26 @@ static void remove_ddw(struct device_node *np, bool remove_prop)
 			np, ret);
 }
 
-static u64 find_existing_ddw(struct device_node *pdn, int *window_shift)
+static bool find_existing_ddw(struct device_node *pdn, u64 *dma_addr, int *window_shift)
 {
 	struct direct_window *window;
 	const struct dynamic_dma_window_prop *direct64;
-	u64 dma_addr = 0;
+	bool found = false;
 
 	spin_lock(&direct_window_list_lock);
 	/* check if we already created a window and dupe that config if so */
 	list_for_each_entry(window, &direct_window_list, list) {
 		if (window->device == pdn) {
 			direct64 = window->prop;
-			dma_addr = be64_to_cpu(direct64->dma_base);
+			*dma_addr = be64_to_cpu(direct64->dma_base);
 			*window_shift = be32_to_cpu(direct64->window_shift);
+			found = true;
 			break;
 		}
 	}
 	spin_unlock(&direct_window_list_lock);
 
-	return dma_addr;
+	return found;
 }
 
 static struct direct_window *ddw_list_new_entry(struct device_node *pdn,
@@ -1161,20 +1162,20 @@ static int iommu_get_page_shift(u32 query_page_size)
  * pdn: the parent pe node with the ibm,dma_window property
  * Future: also check if we can remap the base window for our base page size
  *
- * returns the dma offset for use by the direct mapped DMA code.
+ * returns true if can map all pages (direct mapping), false otherwise..
  */
-static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
+static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
 {
 	int len = 0, ret;
 	int max_ram_len = order_base_2(ddw_memory_hotplug_max());
 	struct ddw_query_response query;
 	struct ddw_create_response create;
 	int page_shift;
-	u64 dma_addr;
 	struct device_node *dn;
 	u32 ddw_avail[DDW_APPLICABLE_SIZE];
 	struct direct_window *window;
 	struct property *win64;
+	bool ddw_enabled = false;
 	struct dynamic_dma_window_prop *ddwprop;
 	struct failed_ddw_pdn *fpdn;
 	bool default_win_removed = false;
@@ -1186,9 +1187,10 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
 
 	mutex_lock(&direct_window_init_mutex);
 
-	dma_addr = find_existing_ddw(pdn, &len);
-	if (dma_addr != 0)
+	if (find_existing_ddw(pdn, &dev->dev.archdata.dma_offset, &len)) {
+		ddw_enabled = true;
 		goto out_unlock;
+	}
 
 	/*
 	 * If we already went through this for a previous function of
@@ -1342,7 +1344,8 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
 	list_add(&window->list, &direct_window_list);
 	spin_unlock(&direct_window_list_lock);
 
-	dma_addr = be64_to_cpu(ddwprop->dma_base);
+	dev->dev.archdata.dma_offset = be64_to_cpu(ddwprop->dma_base);
+	ddw_enabled = true;
 	goto out_unlock;
 
 out_free_window:
@@ -1374,10 +1377,10 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
 	 * as RAM, then we failed to create a window to cover persistent
 	 * memory and need to set the DMA limit.
 	 */
-	if (pmem_present && dma_addr && (len == max_ram_len))
-		dev->dev.bus_dma_limit = dma_addr + (1ULL << len);
+	if (pmem_present && ddw_enabled && (len == max_ram_len))
+		dev->dev.bus_dma_limit = dev->dev.archdata.dma_offset + (1ULL << len);
 
-	return dma_addr;
+	return ddw_enabled;
 }
 
 static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
@@ -1456,11 +1459,8 @@ static bool iommu_bypass_supported_pSeriesLP(struct pci_dev *pdev, u64 dma_mask)
 			break;
 	}
 
-	if (pdn && PCI_DN(pdn)) {
-		pdev->dev.archdata.dma_offset = enable_ddw(pdev, pdn);
-		if (pdev->dev.archdata.dma_offset)
-			return true;
-	}
+	if (pdn && PCI_DN(pdn))
+		return enable_ddw(pdev, pdn);
 
 	return false;
 }
-- 
2.32.0


  parent reply	other threads:[~2021-07-16  8:28 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-16  8:27 [PATCH v5 00/11] DDW + Indirect Mapping Leonardo Bras
2021-07-16  8:27 ` [PATCH v5 01/11] powerpc/pseries/iommu: Replace hard-coded page shift Leonardo Bras
2021-07-19 13:48   ` Frederic Barrat
2021-07-19 18:43     ` Leonardo Brás
2021-07-16  8:27 ` [PATCH v5 02/11] powerpc/kernel/iommu: Add new iommu_table_in_use() helper Leonardo Bras
2021-07-19 13:53   ` Frederic Barrat
2021-07-20  5:38     ` Leonardo Brás
2021-07-20  9:41       ` Alexey Kardashevskiy
2021-07-16  8:27 ` [PATCH v5 03/11] powerpc/pseries/iommu: Add iommu_pseries_alloc_table() helper Leonardo Bras
2021-07-19 14:04   ` Frederic Barrat
2021-07-19 18:47     ` Leonardo Brás
2021-07-16  8:27 ` [PATCH v5 04/11] powerpc/pseries/iommu: Add ddw_list_new_entry() helper Leonardo Bras
2021-07-19 14:14   ` Frederic Barrat
2021-07-19 18:47     ` Leonardo Brás
2021-07-16  8:27 ` Leonardo Bras [this message]
2021-07-20 17:44   ` [PATCH v5 05/11] powerpc/pseries/iommu: Allow DDW windows starting at 0x00 Frederic Barrat
2021-07-16  8:27 ` [PATCH v5 06/11] powerpc/pseries/iommu: Add ddw_property_create() and refactor enable_ddw() Leonardo Bras
2021-07-20 17:49   ` Frederic Barrat
2021-08-17  5:59     ` Leonardo Brás
2021-07-16  8:27 ` [PATCH v5 07/11] powerpc/pseries/iommu: Reorganize iommu_table_setparms*() with new helper Leonardo Bras
2021-07-20 17:50   ` Frederic Barrat
2021-07-16  8:27 ` [PATCH v5 08/11] powerpc/pseries/iommu: Update remove_dma_window() to accept property name Leonardo Bras
2021-07-20 17:51   ` Frederic Barrat
2021-08-17  5:59     ` Leonardo Brás
2021-08-17  6:12       ` Leonardo Brás
2021-08-24  6:31         ` Alexey Kardashevskiy
2021-07-16  8:27 ` [PATCH v5 09/11] powerpc/pseries/iommu: Find existing DDW with given " Leonardo Bras
2021-07-20 17:52   ` Frederic Barrat
2021-07-16  8:27 ` [PATCH v5 10/11] powerpc/pseries/iommu: Make use of DDW for indirect mapping Leonardo Bras
2021-07-20 18:12   ` Frederic Barrat
2021-07-21  3:32     ` Alexey Kardashevskiy
2021-07-21 15:04       ` Frederic Barrat
2021-07-23  5:34         ` Alexey Kardashevskiy
2021-08-17  5:59           ` Leonardo Brás
2021-08-17  5:59       ` Leonardo Brás
2021-07-16  8:27 ` [PATCH v5 11/11] powerpc/pseries/iommu: Rename "direct window" to "dma window" Leonardo Bras
2021-07-20 18:12   ` Frederic Barrat

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