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Commit 97e7dc52 authored by Nishanth Aravamudan's avatar Nishanth Aravamudan Committed by Benjamin Herrenschmidt
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Revert "pseries/iommu: Remove DDW on kexec" 



After reverting 25ebc45b
("powerpc/pseries/iommu: remove default window before attempting DDW
manipulation"), we no longer remove the base window in enable_ddw.
Therefore, we no longer need to reset the DMA window state in
find_existing_ddw_windows(). We can instead go back to what was done
before, which simply reuses the previous configuration, if any. Further,
this removes the final caller of the reset-pe-dma-windows call, so
remove those functions.

This fixes an EEH on kdump with the ipr driver. The EEH occurs, because
the initcall removes the DDW configuration (64-bit DMA window), but
doesn't ensure the ops are via the IOMMU -- a DMA operation occurs
during probe (still investigating this) and we EEH.

This reverts commit 14b6f00f.

Signed-off-by: default avatarNishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent ae69e1ed

arch/powerpc/platforms/pseries/iommu.c

+14 −49
Original line number Original line Diff line number Diff line
@@ -787,68 +787,33 @@ static u64 find_existing_ddw(struct device_node *pdn) 
	return dma_addr;

	return dma_addr;

}

}





static void __restore_default_window(struct eeh_dev *edev,

						u32 ddw_restore_token)

{

	u32 cfg_addr;

	u64 buid;

	int ret;



	/*

	 * Get the config address and phb buid of the PE window.

	 * Rely on eeh to retrieve this for us.

	 * Retrieve them from the pci device, not the node with the

	 * dma-window property

	 */

	cfg_addr = edev->config_addr;

	if (edev->pe_config_addr)

		cfg_addr = edev->pe_config_addr;

	buid = edev->phb->buid;



	do {

		ret = rtas_call(ddw_restore_token, 3, 1, NULL, cfg_addr,

					BUID_HI(buid), BUID_LO(buid));

	} while (rtas_busy_delay(ret));

	pr_info("ibm,reset-pe-dma-windows(%x) %x %x %x returned %d\n",

		 ddw_restore_token, cfg_addr, BUID_HI(buid), BUID_LO(buid), ret);

}



static int find_existing_ddw_windows(void)

static int find_existing_ddw_windows(void)

{

{

	int len;

	struct device_node *pdn;

	struct device_node *pdn;

	struct direct_window *window;

	const struct dynamic_dma_window_prop *direct64;

	const struct dynamic_dma_window_prop *direct64;

	const u32 *ddw_extensions;





	if (!firmware_has_feature(FW_FEATURE_LPAR))

	if (!firmware_has_feature(FW_FEATURE_LPAR))

		return 0;

		return 0;





	for_each_node_with_property(pdn, DIRECT64_PROPNAME) {

	for_each_node_with_property(pdn, DIRECT64_PROPNAME) {

		direct64 = of_get_property(pdn, DIRECT64_PROPNAME, NULL);

		direct64 = of_get_property(pdn, DIRECT64_PROPNAME, &len);

		if (!direct64)

		if (!direct64)

			continue;

			continue;





		/*

		window = kzalloc(sizeof(*window), GFP_KERNEL);

		 * We need to ensure the IOMMU table is active when we

		if (!window || len < sizeof(struct dynamic_dma_window_prop)) {

		 * return from the IOMMU setup so that the common code

			kfree(window);

		 * can clear the table or find the holes. To that end,

		 * first, remove any existing DDW configuration.

		 */

			remove_ddw(pdn);

			remove_ddw(pdn);

			continue;

		}





		/*

		window->device = pdn;

		 * Second, if we are running on a new enough level of

		window->prop = direct64;

		 * firmware where the restore API is present, use it to

		spin_lock(&direct_window_list_lock);

		 * restore the 32-bit window, which was removed in

		list_add(&window->list, &direct_window_list);

		 * create_ddw.

		spin_unlock(&direct_window_list_lock);

		 * If the API is not present, then create_ddw couldn't

		 * have removed the 32-bit window in the first place, so

		 * removing the DDW configuration should be sufficient.

		 */

		ddw_extensions = of_get_property(pdn, "ibm,ddw-extensions",

									NULL);

		if (ddw_extensions && ddw_extensions[0] > 0)

			__restore_default_window(of_node_to_eeh_dev(pdn),

							ddw_extensions[1]);

	}

	}





	return 0;

	return 0;