xref: /linux/arch/mips/pci/msi-octeon.c (revision 4f2c0a4acffbec01079c28f839422e64ddeff004)
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 2005-2009, 2010 Cavium Networks
7  */
8 #include <linux/kernel.h>
9 #include <linux/init.h>
10 #include <linux/msi.h>
11 #include <linux/spinlock.h>
12 #include <linux/interrupt.h>
13 
14 #include <asm/octeon/octeon.h>
15 #include <asm/octeon/cvmx-npi-defs.h>
16 #include <asm/octeon/cvmx-pci-defs.h>
17 #include <asm/octeon/cvmx-npei-defs.h>
18 #include <asm/octeon/cvmx-sli-defs.h>
19 #include <asm/octeon/cvmx-pexp-defs.h>
20 #include <asm/octeon/pci-octeon.h>
21 
22 /*
23  * Each bit in msi_free_irq_bitmask represents a MSI interrupt that is
24  * in use.
25  */
26 static u64 msi_free_irq_bitmask[4];
27 
28 /*
29  * Each bit in msi_multiple_irq_bitmask tells that the device using
30  * this bit in msi_free_irq_bitmask is also using the next bit. This
31  * is used so we can disable all of the MSI interrupts when a device
32  * uses multiple.
33  */
34 static u64 msi_multiple_irq_bitmask[4];
35 
36 /*
37  * This lock controls updates to msi_free_irq_bitmask and
38  * msi_multiple_irq_bitmask.
39  */
40 static DEFINE_SPINLOCK(msi_free_irq_bitmask_lock);
41 
42 /*
43  * Number of MSI IRQs used. This variable is set up in
44  * the module init time.
45  */
46 static int msi_irq_size;
47 
48 /**
49  * arch_setup_msi_irq() - setup MSI IRQs for a device
50  * @dev:    Device requesting MSI interrupts
51  * @desc:   MSI descriptor
52  *
53  * Called when a driver requests MSI interrupts instead of the
54  * legacy INT A-D. This routine will allocate multiple interrupts
55  * for MSI devices that support them. A device can override this by
56  * programming the MSI control bits [6:4] before calling
57  * pci_enable_msi().
58  *
59  * Return: %0 on success, non-%0 on error.
60  */
arch_setup_msi_irq(struct pci_dev * dev,struct msi_desc * desc)61 int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc)
62 {
63 	struct msi_msg msg;
64 	u16 control;
65 	int configured_private_bits;
66 	int request_private_bits;
67 	int irq = 0;
68 	int irq_step;
69 	u64 search_mask;
70 	int index;
71 
72 	if (desc->pci.msi_attrib.is_msix)
73 		return -EINVAL;
74 
75 	/*
76 	 * Read the MSI config to figure out how many IRQs this device
77 	 * wants.  Most devices only want 1, which will give
78 	 * configured_private_bits and request_private_bits equal 0.
79 	 */
80 	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
81 
82 	/*
83 	 * If the number of private bits has been configured then use
84 	 * that value instead of the requested number. This gives the
85 	 * driver the chance to override the number of interrupts
86 	 * before calling pci_enable_msi().
87 	 */
88 	configured_private_bits = (control & PCI_MSI_FLAGS_QSIZE) >> 4;
89 	if (configured_private_bits == 0) {
90 		/* Nothing is configured, so use the hardware requested size */
91 		request_private_bits = (control & PCI_MSI_FLAGS_QMASK) >> 1;
92 	} else {
93 		/*
94 		 * Use the number of configured bits, assuming the
95 		 * driver wanted to override the hardware request
96 		 * value.
97 		 */
98 		request_private_bits = configured_private_bits;
99 	}
100 
101 	/*
102 	 * The PCI 2.3 spec mandates that there are at most 32
103 	 * interrupts. If this device asks for more, only give it one.
104 	 */
105 	if (request_private_bits > 5)
106 		request_private_bits = 0;
107 
108 try_only_one:
109 	/*
110 	 * The IRQs have to be aligned on a power of two based on the
111 	 * number being requested.
112 	 */
113 	irq_step = 1 << request_private_bits;
114 
115 	/* Mask with one bit for each IRQ */
116 	search_mask = (1 << irq_step) - 1;
117 
118 	/*
119 	 * We're going to search msi_free_irq_bitmask_lock for zero
120 	 * bits. This represents an MSI interrupt number that isn't in
121 	 * use.
122 	 */
123 	spin_lock(&msi_free_irq_bitmask_lock);
124 	for (index = 0; index < msi_irq_size/64; index++) {
125 		for (irq = 0; irq < 64; irq += irq_step) {
126 			if ((msi_free_irq_bitmask[index] & (search_mask << irq)) == 0) {
127 				msi_free_irq_bitmask[index] |= search_mask << irq;
128 				msi_multiple_irq_bitmask[index] |= (search_mask >> 1) << irq;
129 				goto msi_irq_allocated;
130 			}
131 		}
132 	}
133 msi_irq_allocated:
134 	spin_unlock(&msi_free_irq_bitmask_lock);
135 
136 	/* Make sure the search for available interrupts didn't fail */
137 	if (irq >= 64) {
138 		if (request_private_bits) {
139 			pr_err("arch_setup_msi_irq: Unable to find %d free interrupts, trying just one",
140 			       1 << request_private_bits);
141 			request_private_bits = 0;
142 			goto try_only_one;
143 		} else
144 			panic("arch_setup_msi_irq: Unable to find a free MSI interrupt");
145 	}
146 
147 	/* MSI interrupts start at logical IRQ OCTEON_IRQ_MSI_BIT0 */
148 	irq += index*64;
149 	irq += OCTEON_IRQ_MSI_BIT0;
150 
151 	switch (octeon_dma_bar_type) {
152 	case OCTEON_DMA_BAR_TYPE_SMALL:
153 		/* When not using big bar, Bar 0 is based at 128MB */
154 		msg.address_lo =
155 			((128ul << 20) + CVMX_PCI_MSI_RCV) & 0xffffffff;
156 		msg.address_hi = ((128ul << 20) + CVMX_PCI_MSI_RCV) >> 32;
157 		break;
158 	case OCTEON_DMA_BAR_TYPE_BIG:
159 		/* When using big bar, Bar 0 is based at 0 */
160 		msg.address_lo = (0 + CVMX_PCI_MSI_RCV) & 0xffffffff;
161 		msg.address_hi = (0 + CVMX_PCI_MSI_RCV) >> 32;
162 		break;
163 	case OCTEON_DMA_BAR_TYPE_PCIE:
164 		/* When using PCIe, Bar 0 is based at 0 */
165 		/* FIXME CVMX_NPEI_MSI_RCV* other than 0? */
166 		msg.address_lo = (0 + CVMX_NPEI_PCIE_MSI_RCV) & 0xffffffff;
167 		msg.address_hi = (0 + CVMX_NPEI_PCIE_MSI_RCV) >> 32;
168 		break;
169 	case OCTEON_DMA_BAR_TYPE_PCIE2:
170 		/* When using PCIe2, Bar 0 is based at 0 */
171 		msg.address_lo = (0 + CVMX_SLI_PCIE_MSI_RCV) & 0xffffffff;
172 		msg.address_hi = (0 + CVMX_SLI_PCIE_MSI_RCV) >> 32;
173 		break;
174 	default:
175 		panic("arch_setup_msi_irq: Invalid octeon_dma_bar_type");
176 	}
177 	msg.data = irq - OCTEON_IRQ_MSI_BIT0;
178 
179 	/* Update the number of IRQs the device has available to it */
180 	control &= ~PCI_MSI_FLAGS_QSIZE;
181 	control |= request_private_bits << 4;
182 	pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, control);
183 
184 	irq_set_msi_desc(irq, desc);
185 	pci_write_msi_msg(irq, &msg);
186 	return 0;
187 }
188 
189 /**
190  * arch_teardown_msi_irq() - release MSI IRQs for a device
191  * @irq:    The devices first irq number. There may be multiple in sequence.
192  *
193  * Called when a device no longer needs its MSI interrupts. All
194  * MSI interrupts for the device are freed.
195  */
arch_teardown_msi_irq(unsigned int irq)196 void arch_teardown_msi_irq(unsigned int irq)
197 {
198 	int number_irqs;
199 	u64 bitmask;
200 	int index = 0;
201 	int irq0;
202 
203 	if ((irq < OCTEON_IRQ_MSI_BIT0)
204 		|| (irq > msi_irq_size + OCTEON_IRQ_MSI_BIT0))
205 		panic("arch_teardown_msi_irq: Attempted to teardown illegal "
206 		      "MSI interrupt (%d)", irq);
207 
208 	irq -= OCTEON_IRQ_MSI_BIT0;
209 	index = irq / 64;
210 	irq0 = irq % 64;
211 
212 	/*
213 	 * Count the number of IRQs we need to free by looking at the
214 	 * msi_multiple_irq_bitmask. Each bit set means that the next
215 	 * IRQ is also owned by this device.
216 	 */
217 	number_irqs = 0;
218 	while ((irq0 + number_irqs < 64) &&
219 	       (msi_multiple_irq_bitmask[index]
220 		& (1ull << (irq0 + number_irqs))))
221 		number_irqs++;
222 	number_irqs++;
223 	/* Mask with one bit for each IRQ */
224 	bitmask = (1 << number_irqs) - 1;
225 	/* Shift the mask to the correct bit location */
226 	bitmask <<= irq0;
227 	if ((msi_free_irq_bitmask[index] & bitmask) != bitmask)
228 		panic("arch_teardown_msi_irq: Attempted to teardown MSI "
229 		      "interrupt (%d) not in use", irq);
230 
231 	/* Checks are done, update the in use bitmask */
232 	spin_lock(&msi_free_irq_bitmask_lock);
233 	msi_free_irq_bitmask[index] &= ~bitmask;
234 	msi_multiple_irq_bitmask[index] &= ~bitmask;
235 	spin_unlock(&msi_free_irq_bitmask_lock);
236 }
237 
238 static DEFINE_RAW_SPINLOCK(octeon_irq_msi_lock);
239 
240 static u64 msi_rcv_reg[4];
241 static u64 mis_ena_reg[4];
242 
octeon_irq_msi_enable_pcie(struct irq_data * data)243 static void octeon_irq_msi_enable_pcie(struct irq_data *data)
244 {
245 	u64 en;
246 	unsigned long flags;
247 	int msi_number = data->irq - OCTEON_IRQ_MSI_BIT0;
248 	int irq_index = msi_number >> 6;
249 	int irq_bit = msi_number & 0x3f;
250 
251 	raw_spin_lock_irqsave(&octeon_irq_msi_lock, flags);
252 	en = cvmx_read_csr(mis_ena_reg[irq_index]);
253 	en |= 1ull << irq_bit;
254 	cvmx_write_csr(mis_ena_reg[irq_index], en);
255 	cvmx_read_csr(mis_ena_reg[irq_index]);
256 	raw_spin_unlock_irqrestore(&octeon_irq_msi_lock, flags);
257 }
258 
octeon_irq_msi_disable_pcie(struct irq_data * data)259 static void octeon_irq_msi_disable_pcie(struct irq_data *data)
260 {
261 	u64 en;
262 	unsigned long flags;
263 	int msi_number = data->irq - OCTEON_IRQ_MSI_BIT0;
264 	int irq_index = msi_number >> 6;
265 	int irq_bit = msi_number & 0x3f;
266 
267 	raw_spin_lock_irqsave(&octeon_irq_msi_lock, flags);
268 	en = cvmx_read_csr(mis_ena_reg[irq_index]);
269 	en &= ~(1ull << irq_bit);
270 	cvmx_write_csr(mis_ena_reg[irq_index], en);
271 	cvmx_read_csr(mis_ena_reg[irq_index]);
272 	raw_spin_unlock_irqrestore(&octeon_irq_msi_lock, flags);
273 }
274 
275 static struct irq_chip octeon_irq_chip_msi_pcie = {
276 	.name = "MSI",
277 	.irq_enable = octeon_irq_msi_enable_pcie,
278 	.irq_disable = octeon_irq_msi_disable_pcie,
279 };
280 
octeon_irq_msi_enable_pci(struct irq_data * data)281 static void octeon_irq_msi_enable_pci(struct irq_data *data)
282 {
283 	/*
284 	 * Octeon PCI doesn't have the ability to mask/unmask MSI
285 	 * interrupts individually. Instead of masking/unmasking them
286 	 * in groups of 16, we simple assume MSI devices are well
287 	 * behaved. MSI interrupts are always enable and the ACK is
288 	 * assumed to be enough
289 	 */
290 }
291 
octeon_irq_msi_disable_pci(struct irq_data * data)292 static void octeon_irq_msi_disable_pci(struct irq_data *data)
293 {
294 	/* See comment in enable */
295 }
296 
297 static struct irq_chip octeon_irq_chip_msi_pci = {
298 	.name = "MSI",
299 	.irq_enable = octeon_irq_msi_enable_pci,
300 	.irq_disable = octeon_irq_msi_disable_pci,
301 };
302 
303 /*
304  * Called by the interrupt handling code when an MSI interrupt
305  * occurs.
306  */
__octeon_msi_do_interrupt(int index,u64 msi_bits)307 static irqreturn_t __octeon_msi_do_interrupt(int index, u64 msi_bits)
308 {
309 	int irq;
310 	int bit;
311 
312 	bit = fls64(msi_bits);
313 	if (bit) {
314 		bit--;
315 		/* Acknowledge it first. */
316 		cvmx_write_csr(msi_rcv_reg[index], 1ull << bit);
317 
318 		irq = bit + OCTEON_IRQ_MSI_BIT0 + 64 * index;
319 		do_IRQ(irq);
320 		return IRQ_HANDLED;
321 	}
322 	return IRQ_NONE;
323 }
324 
325 #define OCTEON_MSI_INT_HANDLER_X(x)					\
326 static irqreturn_t octeon_msi_interrupt##x(int cpl, void *dev_id)	\
327 {									\
328 	u64 msi_bits = cvmx_read_csr(msi_rcv_reg[(x)]);			\
329 	return __octeon_msi_do_interrupt((x), msi_bits);		\
330 }
331 
332 /*
333  * Create octeon_msi_interrupt{0-3} function body
334  */
335 OCTEON_MSI_INT_HANDLER_X(0);
336 OCTEON_MSI_INT_HANDLER_X(1);
337 OCTEON_MSI_INT_HANDLER_X(2);
338 OCTEON_MSI_INT_HANDLER_X(3);
339 
340 /*
341  * Initializes the MSI interrupt handling code
342  */
octeon_msi_initialize(void)343 int __init octeon_msi_initialize(void)
344 {
345 	int irq;
346 	struct irq_chip *msi;
347 
348 	if (octeon_dma_bar_type == OCTEON_DMA_BAR_TYPE_INVALID) {
349 		return 0;
350 	} else if (octeon_dma_bar_type == OCTEON_DMA_BAR_TYPE_PCIE) {
351 		msi_rcv_reg[0] = CVMX_PEXP_NPEI_MSI_RCV0;
352 		msi_rcv_reg[1] = CVMX_PEXP_NPEI_MSI_RCV1;
353 		msi_rcv_reg[2] = CVMX_PEXP_NPEI_MSI_RCV2;
354 		msi_rcv_reg[3] = CVMX_PEXP_NPEI_MSI_RCV3;
355 		mis_ena_reg[0] = CVMX_PEXP_NPEI_MSI_ENB0;
356 		mis_ena_reg[1] = CVMX_PEXP_NPEI_MSI_ENB1;
357 		mis_ena_reg[2] = CVMX_PEXP_NPEI_MSI_ENB2;
358 		mis_ena_reg[3] = CVMX_PEXP_NPEI_MSI_ENB3;
359 		msi = &octeon_irq_chip_msi_pcie;
360 	} else {
361 		msi_rcv_reg[0] = CVMX_NPI_NPI_MSI_RCV;
362 #define INVALID_GENERATE_ADE 0x8700000000000000ULL;
363 		msi_rcv_reg[1] = INVALID_GENERATE_ADE;
364 		msi_rcv_reg[2] = INVALID_GENERATE_ADE;
365 		msi_rcv_reg[3] = INVALID_GENERATE_ADE;
366 		mis_ena_reg[0] = INVALID_GENERATE_ADE;
367 		mis_ena_reg[1] = INVALID_GENERATE_ADE;
368 		mis_ena_reg[2] = INVALID_GENERATE_ADE;
369 		mis_ena_reg[3] = INVALID_GENERATE_ADE;
370 		msi = &octeon_irq_chip_msi_pci;
371 	}
372 
373 	for (irq = OCTEON_IRQ_MSI_BIT0; irq <= OCTEON_IRQ_MSI_LAST; irq++)
374 		irq_set_chip_and_handler(irq, msi, handle_simple_irq);
375 
376 	if (octeon_has_feature(OCTEON_FEATURE_PCIE)) {
377 		if (request_irq(OCTEON_IRQ_PCI_MSI0, octeon_msi_interrupt0,
378 				0, "MSI[0:63]", octeon_msi_interrupt0))
379 			panic("request_irq(OCTEON_IRQ_PCI_MSI0) failed");
380 
381 		if (request_irq(OCTEON_IRQ_PCI_MSI1, octeon_msi_interrupt1,
382 				0, "MSI[64:127]", octeon_msi_interrupt1))
383 			panic("request_irq(OCTEON_IRQ_PCI_MSI1) failed");
384 
385 		if (request_irq(OCTEON_IRQ_PCI_MSI2, octeon_msi_interrupt2,
386 				0, "MSI[127:191]", octeon_msi_interrupt2))
387 			panic("request_irq(OCTEON_IRQ_PCI_MSI2) failed");
388 
389 		if (request_irq(OCTEON_IRQ_PCI_MSI3, octeon_msi_interrupt3,
390 				0, "MSI[192:255]", octeon_msi_interrupt3))
391 			panic("request_irq(OCTEON_IRQ_PCI_MSI3) failed");
392 
393 		msi_irq_size = 256;
394 	} else if (octeon_is_pci_host()) {
395 		if (request_irq(OCTEON_IRQ_PCI_MSI0, octeon_msi_interrupt0,
396 				0, "MSI[0:15]", octeon_msi_interrupt0))
397 			panic("request_irq(OCTEON_IRQ_PCI_MSI0) failed");
398 
399 		if (request_irq(OCTEON_IRQ_PCI_MSI1, octeon_msi_interrupt0,
400 				0, "MSI[16:31]", octeon_msi_interrupt0))
401 			panic("request_irq(OCTEON_IRQ_PCI_MSI1) failed");
402 
403 		if (request_irq(OCTEON_IRQ_PCI_MSI2, octeon_msi_interrupt0,
404 				0, "MSI[32:47]", octeon_msi_interrupt0))
405 			panic("request_irq(OCTEON_IRQ_PCI_MSI2) failed");
406 
407 		if (request_irq(OCTEON_IRQ_PCI_MSI3, octeon_msi_interrupt0,
408 				0, "MSI[48:63]", octeon_msi_interrupt0))
409 			panic("request_irq(OCTEON_IRQ_PCI_MSI3) failed");
410 		msi_irq_size = 64;
411 	}
412 	return 0;
413 }
414 subsys_initcall(octeon_msi_initialize);
415