remoteproc: stm32: Properly handle the resource table when attaching

Properly set the remote processor's resource table based on where it was
loaded by the external entity when attaching to a remote processor.

Mainly based on the work published by Arnaud Pouliquen [1].

[1]. https://patchwork.kernel.org/project/linux-remoteproc/list/?series=239877Acked-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200714200445.1427257-10-mathieu.poirier@linaro.orgSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/remoteproc/stm32_rproc.c

@@ -39,6 +39,8 @@
 #define STM32_MBX_VQ1_ID	1
 #define STM32_MBX_SHUTDOWN	"shutdown"
 
+#define RSC_TBL_SIZE		1024
+
 #define M4_STATE_OFF		0
 #define M4_STATE_INI		1
 #define M4_STATE_CRUN		2
@@ -86,6 +88,7 @@ struct stm32_rproc {
 	struct stm32_mbox mb[MBOX_NB_MBX];
 	struct workqueue_struct *workqueue;
 	bool secured_soc;
+	void __iomem *rsc_va;
 };
 
 static int stm32_rproc_pa_to_da(struct rproc *rproc, phys_addr_t pa, u64 *da)
@@ -669,6 +672,75 @@ static int stm32_rproc_get_m4_status(struct stm32_rproc *ddata,
 	return regmap_read(ddata->m4_state.map, ddata->m4_state.reg, state);
 }
 
+static int stm32_rproc_da_to_pa(struct platform_device *pdev,
+				struct stm32_rproc *ddata,
+				u64 da, phys_addr_t *pa)
+{
+	struct device *dev = &pdev->dev;
+	struct stm32_rproc_mem *p_mem;
+	unsigned int i;
+
+	for (i = 0; i < ddata->nb_rmems; i++) {
+		p_mem = &ddata->rmems[i];
+
+		if (da < p_mem->dev_addr ||
+		    da >= p_mem->dev_addr + p_mem->size)
+			continue;
+
+		*pa = da - p_mem->dev_addr + p_mem->bus_addr;
+		dev_dbg(dev, "da %llx to pa %#x\n", da, *pa);
+
+		return 0;
+	}
+
+	dev_err(dev, "can't translate da %llx\n", da);
+
+	return -EINVAL;
+}
+
+static int stm32_rproc_get_loaded_rsc_table(struct platform_device *pdev,
+					    struct rproc *rproc,
+					    struct stm32_rproc *ddata)
+{
+	struct device *dev = &pdev->dev;
+	phys_addr_t rsc_pa;
+	u32 rsc_da;
+	int err;
+
+	err = regmap_read(ddata->rsctbl.map, ddata->rsctbl.reg, &rsc_da);
+	if (err) {
+		dev_err(dev, "failed to read rsc tbl addr\n");
+		return err;
+	}
+
+	if (!rsc_da)
+		/* no rsc table */
+		return 0;
+
+	err = stm32_rproc_da_to_pa(pdev, ddata, rsc_da, &rsc_pa);
+	if (err)
+		return err;
+
+	ddata->rsc_va = devm_ioremap_wc(dev, rsc_pa, RSC_TBL_SIZE);
+	if (IS_ERR_OR_NULL(ddata->rsc_va)) {
+		dev_err(dev, "Unable to map memory region: %pa+%zx\n",
+			&rsc_pa, RSC_TBL_SIZE);
+		ddata->rsc_va = NULL;
+		return -ENOMEM;
+	}
+
+	/*
+	 * The resource table is already loaded in device memory, no need
+	 * to work with a cached table.
+	 */
+	rproc->cached_table = NULL;
+	/* Assuming the resource table fits in 1kB is fair */
+	rproc->table_sz = RSC_TBL_SIZE;
+	rproc->table_ptr = (struct resource_table *)ddata->rsc_va;
+
+	return 0;
+}
+
 static int stm32_rproc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -708,6 +780,10 @@ static int stm32_rproc_probe(struct platform_device *pdev)
 		ret = stm32_rproc_parse_memory_regions(rproc);
 		if (ret)
 			goto free_resources;
+
+		ret = stm32_rproc_get_loaded_rsc_table(pdev, rproc, ddata);
+		if (ret)
+			goto free_resources;
 	}
 
 	rproc->has_iommu = false;