cxl: EEH support (9e8df8a2) · Commits · e / devices / android_kernel_teracube_emerald

drivers/misc/cxl/cxl.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -726,6 +726,7 @@ int cxl_psl_purge(struct cxl_afu *afu);

		void cxl_stop_trace(struct cxl *cxl);
		int cxl_pci_vphb_add(struct cxl_afu *afu);
		void cxl_pci_vphb_reconfigure(struct cxl_afu *afu);
		void cxl_pci_vphb_remove(struct cxl_afu *afu);

		extern struct pci_driver cxl_pci_driver;

drivers/misc/cxl/pci.c

+253 −0

Original line number	Diff line number	Diff line
		@@ -24,6 +24,7 @@
		#include <asm/io.h>

		#include "cxl.h"
		#include <misc/cxl.h>


		#define CXL_PCI_VSEC_ID 0x1280
		@@ -1252,10 +1253,262 @@ static void cxl_remove(struct pci_dev *dev)
		cxl_remove_adapter(adapter);
		}

		static pci_ers_result_t cxl_vphb_error_detected(struct cxl_afu *afu,
		pci_channel_state_t state)
		{
		struct pci_dev *afu_dev;
		pci_ers_result_t result = PCI_ERS_RESULT_NEED_RESET;
		pci_ers_result_t afu_result = PCI_ERS_RESULT_NEED_RESET;

		/* There should only be one entry, but go through the list
		* anyway
		*/
		list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {
		if (!afu_dev->driver)
		continue;

		afu_dev->error_state = state;

		if (afu_dev->driver->err_handler)
		afu_result = afu_dev->driver->err_handler->error_detected(afu_dev,
		state);
		/* Disconnect trumps all, NONE trumps NEED_RESET */
		if (afu_result == PCI_ERS_RESULT_DISCONNECT)
		result = PCI_ERS_RESULT_DISCONNECT;
		else if ((afu_result == PCI_ERS_RESULT_NONE) &&
		(result == PCI_ERS_RESULT_NEED_RESET))
		result = PCI_ERS_RESULT_NONE;
		}
		return result;
		}

		static pci_ers_result_t cxl_pci_error_detected(struct pci_dev *pdev,
		pci_channel_state_t state)
		{
		struct cxl *adapter = pci_get_drvdata(pdev);
		struct cxl_afu *afu;
		pci_ers_result_t result = PCI_ERS_RESULT_NEED_RESET;
		int i;

		/* At this point, we could still have an interrupt pending.
		* Let's try to get them out of the way before they do
		* anything we don't like.
		*/
		schedule();

		/* If we're permanently dead, give up. */
		if (state == pci_channel_io_perm_failure) {
		/* Tell the AFU drivers; but we don't care what they
		* say, we're going away.
		*/
		for (i = 0; i < adapter->slices; i++) {
		afu = adapter->afu[i];
		cxl_vphb_error_detected(afu, state);
		}
		return PCI_ERS_RESULT_DISCONNECT;
		}

		/* Are we reflashing?
		*
		* If we reflash, we could come back as something entirely
		* different, including a non-CAPI card. As such, by default
		* we don't participate in the process. We'll be unbound and
		* the slot re-probed. (TODO: check EEH doesn't blindly rebind
		* us!)
		*
		* However, this isn't the entire story: for reliablity
		* reasons, we usually want to reflash the FPGA on PERST in
		* order to get back to a more reliable known-good state.
		*
		* This causes us a bit of a problem: if we reflash we can't
		* trust that we'll come back the same - we could have a new
		* image and been PERSTed in order to load that
		* image. However, most of the time we actually will come
		* back the same - for example a regular EEH event.
		*
		* Therefore, we allow the user to assert that the image is
		* indeed the same and that we should continue on into EEH
		* anyway.
		*/
		if (adapter->perst_loads_image && !adapter->perst_same_image) {
		/* TODO take the PHB out of CXL mode */
		dev_info(&pdev->dev, "reflashing, so opting out of EEH!\n");
		return PCI_ERS_RESULT_NONE;
		}

		/*
		* At this point, we want to try to recover. We'll always
		* need a complete slot reset: we don't trust any other reset.
		*
		* Now, we go through each AFU:
		* - We send the driver, if bound, an error_detected callback.
		* We expect it to clean up, but it can also tell us to give
		* up and permanently detach the card. To simplify things, if
		* any bound AFU driver doesn't support EEH, we give up on EEH.
		*
		* - We detach all contexts associated with the AFU. This
		* does not free them, but puts them into a CLOSED state
		* which causes any the associated files to return useful
		* errors to userland. It also unmaps, but does not free,
		* any IRQs.
		*
		* - We clean up our side: releasing and unmapping resources we hold
		* so we can wire them up again when the hardware comes back up.
		*
		* Driver authors should note:
		*
		* - Any contexts you create in your kernel driver (except
		* those associated with anonymous file descriptors) are
		* your responsibility to free and recreate. Likewise with
		* any attached resources.
		*
		* - We will take responsibility for re-initialising the
		* device context (the one set up for you in
		* cxl_pci_enable_device_hook and accessed through
		* cxl_get_context). If you've attached IRQs or other
		* resources to it, they remains yours to free.
		*
		* You can call the same functions to release resources as you
		* normally would: we make sure that these functions continue
		* to work when the hardware is down.
		*
		* Two examples:
		*
		* 1) If you normally free all your resources at the end of
		* each request, or if you use anonymous FDs, your
		* error_detected callback can simply set a flag to tell
		* your driver not to start any new calls. You can then
		* clear the flag in the resume callback.
		*
		* 2) If you normally allocate your resources on startup:
		* * Set a flag in error_detected as above.
		* * Let CXL detach your contexts.
		* * In slot_reset, free the old resources and allocate new ones.
		* * In resume, clear the flag to allow things to start.
		*/
		for (i = 0; i < adapter->slices; i++) {
		afu = adapter->afu[i];

		result = cxl_vphb_error_detected(afu, state);

		/* Only continue if everyone agrees on NEED_RESET */
		if (result != PCI_ERS_RESULT_NEED_RESET)
		return result;

		cxl_context_detach_all(afu);
		cxl_afu_deactivate_mode(afu);
		cxl_deconfigure_afu(afu);
		}
		cxl_deconfigure_adapter(adapter);

		return result;
		}

		static pci_ers_result_t cxl_pci_slot_reset(struct pci_dev *pdev)
		{
		struct cxl *adapter = pci_get_drvdata(pdev);
		struct cxl_afu *afu;
		struct cxl_context *ctx;
		struct pci_dev *afu_dev;
		pci_ers_result_t afu_result = PCI_ERS_RESULT_RECOVERED;
		pci_ers_result_t result = PCI_ERS_RESULT_RECOVERED;
		int i;

		if (cxl_configure_adapter(adapter, pdev))
		goto err;

		for (i = 0; i < adapter->slices; i++) {
		afu = adapter->afu[i];

		if (cxl_configure_afu(afu, adapter, pdev))
		goto err;

		if (cxl_afu_select_best_mode(afu))
		goto err;

		cxl_pci_vphb_reconfigure(afu);

		list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {
		/* Reset the device context.
		* TODO: make this less disruptive
		*/
		ctx = cxl_get_context(afu_dev);

		if (ctx && cxl_release_context(ctx))
		goto err;

		ctx = cxl_dev_context_init(afu_dev);
		if (!ctx)
		goto err;

		afu_dev->dev.archdata.cxl_ctx = ctx;

		if (cxl_afu_check_and_enable(afu))
		goto err;

		afu_dev->error_state = pci_channel_io_normal;

		/* If there's a driver attached, allow it to
		* chime in on recovery. Drivers should check
		* if everything has come back OK, but
		* shouldn't start new work until we call
		* their resume function.
		*/
		if (!afu_dev->driver)
		continue;

		if (afu_dev->driver->err_handler &&
		afu_dev->driver->err_handler->slot_reset)
		afu_result = afu_dev->driver->err_handler->slot_reset(afu_dev);

		if (afu_result == PCI_ERS_RESULT_DISCONNECT)
		result = PCI_ERS_RESULT_DISCONNECT;
		}
		}
		return result;

		err:
		/* All the bits that happen in both error_detected and cxl_remove
		* should be idempotent, so we don't need to worry about leaving a mix
		* of unconfigured and reconfigured resources.
		*/
		dev_err(&pdev->dev, "EEH recovery failed. Asking to be disconnected.\n");
		return PCI_ERS_RESULT_DISCONNECT;
		}

		static void cxl_pci_resume(struct pci_dev *pdev)
		{
		struct cxl *adapter = pci_get_drvdata(pdev);
		struct cxl_afu *afu;
		struct pci_dev *afu_dev;
		int i;

		/* Everything is back now. Drivers should restart work now.
		* This is not the place to be checking if everything came back up
		* properly, because there's no return value: do that in slot_reset.
		*/
		for (i = 0; i < adapter->slices; i++) {
		afu = adapter->afu[i];

		list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {
		if (afu_dev->driver && afu_dev->driver->err_handler &&
		afu_dev->driver->err_handler->resume)
		afu_dev->driver->err_handler->resume(afu_dev);
		}
		}
		}

		static const struct pci_error_handlers cxl_err_handler = {
		.error_detected = cxl_pci_error_detected,
		.slot_reset = cxl_pci_slot_reset,
		.resume = cxl_pci_resume,
		};

		struct pci_driver cxl_pci_driver = {
		.name = "cxl-pci",
		.id_table = cxl_pci_tbl,
		.probe = cxl_probe,
		.remove = cxl_remove,
		.shutdown = cxl_remove,
		.err_handler = &cxl_err_handler,
		};

drivers/misc/cxl/vphb.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -266,6 +266,14 @@ int cxl_pci_vphb_add(struct cxl_afu *afu)
		return 0;
		}

		void cxl_pci_vphb_reconfigure(struct cxl_afu *afu)
		{
		/* When we are reconfigured, the AFU's MMIO space is unmapped
		* and remapped. We need to reflect this in the PHB's view of
		* the world.
		*/
		afu->phb->cfg_addr = afu->afu_desc_mmio + afu->crs_offset;
		}

		void cxl_pci_vphb_remove(struct cxl_afu *afu)
		{